RM7890, RM7895 100 Vac

7800 SERIES Relay Modules

INSTALLATION INSTRUCTIONS

The RM7890, RM7895 provides on/off automatic burner se-

quencing, flame supervision, system status indication, system
or self-diagnostics and troubleshooting. The RM7895 in-
cludes an output for the blower motor to provide purging.
This document provides installation and static checkout in-
structions. Other applicable publications are:
Table 1. Other applicable publications.

Form Description
number
65-0249 S7810M Modbus Module
65-0084 Q7800A,B 22-Terminal Wiring Subbase Product
Data
65-0090 S7800A 2-line VFD Keyboard Display Module
Product Data.
65-0091 S7810A Data ControlBus Module™ Product Data
APPLICATION
65-0095 S7820 Remote Reset Module Product Data
The Honeywell RM7890B, RM7895A Relay Modules are mi-
croprocessor based integrated burner controls for automat- 65-0097 221729C Dust Cover Packing Sheet
ically fired gas, oil or combination fuel single burner On/Off 65-0109 R7824, R7847, R7848, R7849, R7851, R7852,
applications. The RM7890B; RM7895A System consists of R7861, R7886 Flame Amplifiers for the 7800
the relay module, wiring subbase, amplifier and the RM7895A SERIES Product Data
also requires a purge timer. Options include Keyboard Display
65-0295 NEMA4 covers for 2-line VF KDM, 50023821-
Module (KDM), Data ControlBus™ Module, remote display 001 w/o reset, 50023821-002 with reset
mounting and Modbus communications is available using the
S7810M Modbus Module or configuring the S7800 KDM. 32-00110 4-line LCD KDM S7800A2142
32-00166 NEMA4 covers for 4-line KDM, 204729A w/o
The RM7890; RM7895 is programmed to provide a level of reset, 204729B with reset
safety, functional capability and features beyond the capacity
of conventional controls. 65-0131 221818A Extension Cable Assembly Product
Data
This document covers the following models:
65-0229 7800 SERIES Relay Modules Checkout and
RM7890B1063 Troubleshooting
RM7895A1089

CONTENTS
APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
OPTIONAL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 INITIATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 STANDBY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
PRINCIPAL TECHNICAL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . 6 STATIC CHECKOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SAFETY PROVISIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 CHECKOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
WIRING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 SAFETY AND SECURITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

SIL3
Capable
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RM7890, RM7895 100 Vac

FEATURES SPECIFICATIONS
• Safety features: Electrical Ratings:
—— Closed loop logic test. See Table 2.
—— Dynamic AMPLI-CHECK™ circuitry.
Voltage and Frequency:
—— Dynamic input check.
100 Vac (+10/-15%), 50/60 Hz (± 10%).
—— Dynamic safety relay test.
Power Dissipation: 10W maximum.
—— Dynamic self-check logic. Maximum Total Connected Load: 2000 VA.
—— Expanded safe-start check. Fusing Total Connected Load: 15A maximum, type SC or
—— Internal hardware status monitoring. equivalent.
—— Tamper resistant timing and logic.
Environmental Ratings:
• Access for external electrical voltage checks. Application
Ambient Temperature:
flexibility.
Operating: -40°F to 140°F (-40°C to 60°C).
• Dependable, long-term operation provided by microcom- Storage: -60°F to 150°F (-51°C to 66°C).
puter technology. Humidity: 85% relative humidity continuous, noncondensing.
• Five light emitting diodes (LEDs) for sequence informa- Vibration: 0.5G environment.
tion. Dimensions:
• Interchangeable type plug-in flame amplifiers. See Fig. 1 and 2.
• Nonvolatile memory retains history files and sequencing Weight:
status after loss of power. RM7890, RM7895 with Dust Cover: 1 lb, 13 oz (829 grams)
unpacked.
• Selectable relight or lockout on loss of flame.
Approvals:
cULus Underwriters Laboratories Inc. Listed: File No. MP268.
OPTIONAL FEATURES ANSI/UL 60730-2-5 / CSA C22.2 No. 60730-2-5 -
• Communication interface capability. ­Automatic Electrical Controls for Household and Similar
Use, Part 2-5: Particular Requirements for Automatic
• First-out annunciation and system diagnosis are provided Electrical Burner Control Systems.
by a two-row by 20-column display located on the option- FM: Factory Mutual Approved: Report No. 1V9A0.AF.
al keyboard display module (KDM). EAC: TC N RU д-US.Aи3O.B.04013
• Local or remote annunciation operation and fault informa- Exida: IEC/EN 61508:2010 Parts 1-7, SIL 3 capable.
tion. FCC Federal Communications Commission: Part 15, Class B,
• Remote reset. Emissions.
Swiss Re (formerly Industrial Risk Insurers): Acceptable.
• Burner controller data using S7800 Keyboard Display:
Mounting:
—— Flame signal strength.
Q7800A Wiring Subbase for panel mounting.
—— Hold status.
Q7800B Wiring Subbase for wall or burner mounting.
—— Lockout/alarm status.
—— Sequence status. Required Components:
—— Sequence time. Plug-in Flame Signal Amplifier (See Table 4).
—— Total cycles of operation. ST7800A Purge Timer (for RM7895 only).
—— Total hours of operation. Accessories:
• Fault history providing the six most recent faults:
• Cycles of operation at the time of the fault. Keyboard Display Modules (KDM)
• Fault message and code. S7800A1142 2-Line VFD Keyboard Display Module
• Hours of operation at the time of the fault. S7800A2142 4-line LCD keyboard display module
• Sequence status at the time of the fault. Communications
• Sequence time at the time of the fault. Modbus using S7810M1003 Modbus Module
—— Diagnostic information: or
• Device type. configuring the S7800 Keyboard Display.
• Flame amplifier type. S7810A1009 Data ControlBus™ Module (if no KDM used).
• Flame failure response time. Manufacturing code. Miscellaneous
• On/Off status of all digital inputs and outputs. A7800A1002 7800 SERIES Tester
• Software revision and version of RM7890/ RM7895 S7820A1007 Remote Reset Module
and optional Keyboard Display Module.
203541 Data ControlBus Connector, 5-wire
• Status of configuration jumpers.
203765 Remote Display Mounting Bracket
221729 Dust Cover, Relay Module

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 RM7890, RM7895 100 Vac

50023821-001 2-Line Keyboard Display Module Cover,

NEMA 4, clear
50023821-002 2-Line Keyboard Display Module Cover,
NEMA 4, clear with reset button
205321B Flush Display Mounting Kit. Display Module Cover
for 4-line LCD: 204729A w/o reset button, 204729C with
reset button
221818A Extension Cable, display, 5 ft (1.52 m)
221818C Extension Cable, display, 10 ft (3.05 m)
123514A Rectification Flame Simulator
203569 Ultraviolet Flame Simulator
IMPORTANT
A flame detection system is required for operation and must
be ordered separately. Select the applicable flame signal
amplifier and matching flame detector from Table 5.
Table 2. RM7890, RM7895 Terminal Ratings.

Terminal No. Description Ratings

G Flame Sensor Grounda —
Earth G Earth Grounda —
L2(N) Line Voltage Common —
3 (RM7890) Line Voltage Supply (L1) 100 Vac (+10%/-15%), 50/60 Hz
(±10%).b
3 (RM7895) Alarm 100 Vac, 1A pilot duty.
4 (RM7890) Alarm 100 Vac, 1A pilot duty.
4 (RM7895) Burner Motor 100 Vac, 9.8AFL, 58.8ALR (inrush).
5 (RM7890) Unused —
5 (RM7895) Line Voltage Supply (L1) 100 Vac (+10%/-15%), 50/60 Hz
(±10%).b
6 (RM7890) Burner Controller and Limits 100 Vac 8A Run, 43A inrush.b
6 (RM7895) Burner Controller and Limits 100 Vac, 1 mA.
7 (RM7890) Unused —
7 (RM7895) Airflow Interlock 100 Vac, 8A run, 43A inrush.
8 Pilot Valve/Ignition 100 Vac.c
9 Main Fuel Valve
10 Ignition
F(11) Flame Sensor 60–220 Vac, current limited.
12 to 22 Unused —
a The RM7890 and RM7895 must have an earth ground providing a connection between the wiring subbase and the control panel or
equipment. The earth ground wire must be capable of conducting the current to blow a 15A Fast Blow, Type SC, fuse (or equivalent) in the
event of an internal short circuit. The RM7890 and RM7895 need a low impedance ground connection to the equipment frame, which, in turn,
needs a low impedance connection to earth ground.
b 2000 VA maximum connected load to the Relay Module.
c See Table 3 and 4.

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Table 3. Combinations for terminals 8, 9 and 10.

Pilot Valve (Terminal 8) Main Fuel Valve (Terminal 9) Ignition (Terminal 10)
C F A
B F No Load
F F A
F No Load A
D F A
D D A
D No Load A
Table 4. Composition of Each Combination.

A B C D F
4.5A ignition 50 VA Pilot Duty plus 180 VA ignition plus 2A Pilot Duty 65 VA Pilot Duty plus
4.5A ignition. motor valves with: Motor valves with:
660 VA inrush 3850 VA inrush
360 VA open 700 VA open
250 VA hold. 250 VA hold.

Fig. 1. Mounting dimensions of RM7890, RM7895 Relay Module and Q7800A Subbase in in. (mm).

Fig. 2. Mounting dimensions of RM7890, RM7895 Relay Module and Q7800B Subbase in in. (mm).
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 RM7890, RM7895 100 Vac

Table 5. Flame Detection Systems.

Plug-in Flame Signal Amplifiers Applicable Flame Detectors

Type Color Self-Checking Model Flame Failure Fuel Type Models
Response
Timea

Rectification Green No R7847Ae 0.8 or 3.0 sec. Gas Rectifying C7004, C7007, C7011.
Flame Rod Complete Assemblies:
Holdersf C7008, C7009, Q179

No R7847Ae 3.0 sec Gas, oil, Ultraviolet C7012A,C

coal (Purple
Peeper®)
Dynamic R7847Bc,e 0.8 or 3.0 sec Gas Rectifying C7004, C7007, C7011.
AMPLI-CHECK® Flame Rod Complete Assemblies:
Holdersf C7008, C7009, Q179

Dynamic R7847Bc,e 3.0 sec Gas, oil, Ultraviolet C7012A,C

Ampli-Check® coal (Purple
Peeper®)
Infrared Red/ No R7852A 3.0 sec. Gas, oil, Infrared C7915
White coal (Lead
Dynamic R7852Bc Sulfide)
AMPLI-CHECK®
Ultraviolet Purple No R7849A 0.8 or 3.0 sec Gas, oil Ultraviolet C7027, C7035, C7044 d
(Minipeeper)
Dynamic R7849Bc 0.8 or 3.0 sec Gas, oil Ultraviolet C7027, C7035, C7044 d
Ampli-Check® (Minipeeper)
Dynamic R7861Ab 0.8 or 3.0 sec Gas, oil, Ultraviolet C7061
Self-Check coal
Blue Dynamic R7886A,Mb 3.0 sec Gas, oil, Ultraviolet C7076
Self-Check coal (Adjustable
Sensitivity)
Optical White Dynamic R7851B 0.8 or 3.0 sec Gas, oil, Optical (UV, C7927, C7962
Ampli-Check® coal Visible Light)
Dynamic R7851Cb 3.0 sec Gas, oil, Optical (UV C7961
Self-Check coal only)
a Flame Failure Response Time (FFRT) depends on selection of amplifier.
b Circuitry tests all electronic components in flame detection system (amplifier and detector) 12 times a minute during burner operation and
shuts down burner if detection system fails.
c Circuitry tests flame signal amplifier 12 times a minute during burner operation and shuts down burner if amplifier fails.
d Use C7027, C7035 and C7044 Flame Detectors only on burners that cycle on-off at least once every twenty-four hours. Use C7061A,M
Ultraviolet Detector with R7861A Amplifier or C7076A Flame Detector with R7886A Amplifier as ultraviolet flame detection system for
appliances with burners that remain on continuously for twenty-four hours or longer.
e R7847A,B Amplifiers with 0.8 second FFRT should NOT be used with C7012A,C Solid State Ultraviolet Detectors.
f Order flame rod separately, see flame detector Instructions for holder.

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RM7890, RM7895 100 Vac

Table 6. Sequence Timing for Normal Operation.

Device Initiate Standbya Purgeb Pilot Flame Establishing Period Runa

RM7890 10 sec. — N/A 4 or 10 sec. —
RM7895 10 sec. — — 4 or 10 sec. —
a Standby and Run can be an infinite time period.
b Purge is determined by the ST7800 Purge Timing Card selected (RM7895 only).

g. Purge card is faulty (RM7895 only).

PRINCIPAL TECHNICAL FEATURES
6. RUN PERIOD.
The RM7890 and RM7895 Relay Modules provide all custom- a. Ignition terminal is energized when it should be off.
ary flame safeguard functions while providing significant ad- b. Internal system fault occurred.
vancements in the areas of safety, annunciation and system c. Main valve terminal is not energized when it should be
diagnostics. on.
d. No flame is present and configuration jumper is select-
Safety Shutdown (Lockout) Occurs If: ed for lockout.
e. Pilot valve terminal is not energized.
1. INITIATE PERIOD f. Airflow lockout feature is enabled and the airflow switch
a. AC line power errors occurred; see Operations section. opens (RM7895).
b. Configuration jumpers are changed after 200 hours of g. Purge card is not installed or was removed (RM7895
operation. only).
c. Four minute INITIATE period has been exceeded. h. Purge card is faulty (RM7895 only).
d. Purge card is not installed or was removed (RM7895
only).
e. Purge card is faulty. SAFETY PROVISIONS
2. STANDBY PERIOD
a. Flame signal is present after 240 seconds. Internal Hardware Status Monitoring
b. Ignition/intermittent pilot valve terminal is powered
The RM7890; RM7895 Relay Modules analyze the integri-
when it should be off.
ty of the configuration jumpers and internal hardware. The
c. Internal system fault occurred.
RM7895 checks the purge card for correct parity to prevent
d. Main valve terminal is powered when it should be off.
purge timing shifts and circuitry failures. The POWER LED
e. Three-second flame failure response time (FFRT) ampli-
will blink every four seconds, signifying an internal hardware
fier is installed and configuration jumper is selected for
check.
relight (RM7890); see Table 8.
f. Purge card is not installed or was removed (RM7895).
g. Purge card is faulty. Closed Loop Logic Test
3. SAFE START CHECK The test verifies the integrity of all safety critical loads, termi-
a. Ignition/intermittent pilot valve terminal is energized nals 8, 9 and 10. If the loads are not energized properly— that
when it should be off. is, the main valve terminal is powered during STANDBY— the
b. Internal system fault occurred. relay module locks out on safety shutdown. The relay mod-
c. Main valve terminal is energized. ule must react to input changes but avoid the occurrence of
4. PREPURGE PERIOD (RM7895 Only). nuisance shutdown events. Signal conditioning is applied to
a. Airflow lockout feature is enabled and the airflow switch line voltage inputs to verify proper operation in the presence
does not close after ten seconds or within the specified of normal electrical line noises such as transient high voltage
purge card timing. spikes or short periods of line dropout. Signal conditioning is
b. Flame signal is detected after 30 seconds. tolerant of synchronous noise (line noise events that occur at
c. Ignition/pilot valve/intermittent pilot valve terminal is the same time during each line cycle).
energized when it should be off.
d. Main valve terminal is energized when it should be off.
Dynamic AMPLI-CHECK TM Circuitry
e. Internal system fault occurred.
f. Purge card is not installed or was removed. Dynamic AMPLI-CHECK TM circuitry tests the flame signal
g. Purge card is faulty. amplifier during burner operation and shuts down the relay
5. PILOT FLAME ESTABLISHING PERIOD (PFEP). module if the flame amplifier fails.
a. Ignition/intermittent pilot valve terminal is not ener-
gized. Dynamic Input Check
b. Internal system fault occurred.
c. Main valve terminal is energized when it should be off. All system input circuits are examined to assure that the relay
d. No flame present at end of PFEP. module is capable of recognizing the true status of external
e. Airflow lockout feature is enabled and the airflow switch controls, limits and interlocks. If any input fails this test, a
opens (RM7895). safety shutdown occurs and the fault will be annunciated.
f. Purge card is not installed or was removed (RM7895
only).

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 RM7890, RM7895 100 Vac

Dynamic Safety Relay Test Self-Diagnostics add to the First-Out Annunciation by allow-
ing the relay module to distinguish between field (external
Checks the ability of the dynamic safety relay contact to open device) and internal (system related) problems. Faults asso-
and close. Verifies that the safety critical loads, terminals 8, 9 ciated within the flame detection subsystem or relay module
and 10 can be de-energized, as required, by the Dynamic Self- are isolated and reported by the optional KDM. See the 7800
Check logic. SERIES Relay Modules Checkout and Troubleshooting, form
65-0229.
Dynamic Self-Check Safety Circuit
The microcomputer tests itself and related hardware, and at
Interlock Requirements (RM7895 Only)
the same time, the safety relay system tests the microcom- The Airflow Switch Interlock input provided in the RM7895 is
puter operation. If a microcomputer or safety relay failure oc- typically connected to an airflow switch. The Airflow Interlock
curs and does not allow proper execution of the (ILK) input must close ten seconds into PREPURGE or within
self-check routine, safety shutdown occurs and all safety crit- the specified purge card timing; otherwise, a recycle to the be-
ical loads will be de-energized. ginning of PREPURGE or lockout occurs, depending on how
the airflow switch selectable jumper is configured (see Table 5
Expanded Safe-Start Check in the Operation section).

The conventional safe-start check, which prevents burner

startup when flame is indicated at startup, is expanded to INSTALLATION
include a flame signal check during STANDBY and a safety
critical load check. WARNING
Fire or Explosion Hazard.
Off Cycle (Standby) Flame Signal Check Can cause severe injury, death or property damage.
The flame detection subsystem (flame detector and amplifier) To prevent possible hazardous burner operation, verify
is monitored during STANDBY. If a flame simulating con- local safety requirements are observed each time a
dition or an actual flame exists for 240 seconds in STAND- control is installed on a burner.
BY, a system hold occurs and startup is prevented. If the
flame signal exists at any time after the 240 seconds during
STANDBY, a safety shutdown occurs and is annunciated. An
WARNING
AMPLI-CHECK™ Amplifier is energized continually through Electrical Shock Hazard or Equipment Damage
STANDBY (and PREPURGE in the RM7895) to detect any Hazard.
possibility of a runaway detector or a flame. When a flame Can cause severe injury, death or equipment and
exists, a safety shutdown occurs. A standard amplifier is en- control damage.
ergized continually through STANDBY (and PREPURGE in the Disconnect the power supply before beginning
RM7895). When a flame exists, a safety shutdown occurs. installation.

Tamper Resistant Timing and Logic When Installing this Product…

Safety and logic timings are inaccessible and cannot be al-
1. Read these instructions carefully. Failure to follow them
tered or defeated.
could damage the product or cause a hazardous condition.
2. Check the ratings given in the instructions and marked on
Verified Spark Termination the product to make sure the product is suitable for the
The ignition terminal is monitored to assure spark termination. application.
3. Installer must be a trained, experienced, flame
safeguard service technician.
First-Out Annunciation and Self-Diagnostics
4. After installation is complete, check out the product opera-
Sequence Status Lights (LED) provide positive visual indi- tion as provided in these instructions.
cation of the program sequence: POWER, PILOT, FLAME,
MAIN and ALARM. The green POWER LED blinks every four
seconds, signifying that the relay module hardware is running IMPORTANT
correctly. 1. Wiring connections for the relay modules are unique; re-
fer to Fig. 6 and 7 or the correct Specifications for proper
The optional multi-functional KDM shows elapsed time during
subbase wiring.
PILOT IGN. As an additional troubleshooting aid, it provides
sequence timing, diagnostic information, historical informa- 2. Wiring must comply with all applicable codes, ordinanc-
tion and expanded annunciator information during normal es and regulations.
operation or when a safety shutdown or hold occurs. 3. Wiring must comply with NEC Class 1 (Line Voltage) wir-
ing.
First-out Annunciation reports the cause of safety shutdown
or identifies the cause of a failure to start or continue the 4. Loads connected to the relay module must not exceed
burner control sequence with text and numbered code using those listed on the relay module label or the Specifica-
the optional KDM. It monitors all field input circuits, including tions; see Table 1.
the flame signal amplifier.

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RM7890, RM7895 100 Vac

5. Limits and interlocks must be rated to simultaneously 204718A Remote Display Cover Assembly or other suitable
carry and break current to the ignition transformer, pilot enclosure that meets IP40 class of protection.
valve, and main fuel valve(s).
6. All external timers must be Listed or Component-Recog- Relay Module and Subbase Compatiblity
nized by authorities who have proper jurisdiction.
NOTE: There are several different subbase models that can
7. For on-off gas-fired systems, some authorities who have be purchased. It is important to insure that the sub-
jurisdiction prohibit the wiring of any limit or operating base is compatible with the relay module when pur-
contacts in series between the flame chasing new, repair or replacement parts.
safeguard control and the main fuel valve(s).
This model will only be available as the 1000 Series Relay
8. Two flame detectors can be connected in parallel with the
Modules, if you have subbase incompatibly issues please see
exception of Flame Detectors C7915, C7927,C7961 and
below.
C7962.
9. This equipment generates, uses and can radiate radio Series 1000 Relay Modules
frequency energy and, if not installed and used in accor-
dance with the instructions, can cause interference with All relay product codes that start with a 1 (example:
radio communications. It has been tested and found to RM7840G1014/U) can be used with existing subbase
comply with the limits for a Class B computing device Q7800A1003/U and Q7800A1005/U.
of Part 15 of FCC rules which are designed to provide
reasonable protection against such interference when Subbase Compatibility
operated in a commercial environment. Operation of this
equipment in a residential area may cause interference; Any Relay Module in the 1000 Series with a Software Revision
in which case, the users at their own expense may be re- level number starting with a “5” or greater will be compatible
quired to take whatever measures are required to correct with all subbase models both installed and newly purchased.
this interference. This includes (Q7800A1005/U, Q7800B1003/U), and the
2000 Series subbases (Q7800A2005/U, Q7800B2003/U).
10. This digital apparatus does not exceed the Class B limits
for radio noise for digital apparatus set out in the Radio See Fig. 3 for Software Revision Level number location on the
Interference Regulations of the Canadian Department of label (located on the rear of the relay module).
Communications.

Location
Humidity
Install the relay module where the relative humidity never
reaches the saturation point. The relay module is designed
to operate in a maximum 85% relative humidity continuous,
noncondensing, moisture environment. Condensing moisture
can cause a safety shutdown.
Fig. 3. Software revision location
Vibration
Do not install the relay module where it could be subjected to IMPORTANT
vibration in excess of 0.5G continuous maximum vibration.
Make sure to check the relay model number and the soft-
Weather ware revision level on the relay.
If you receive an error code of 101. This indicates that you
The relay module is not designed to be weather tight. When have the wrong subbase model. YOu must change out the
installed outdoors, locate the relay module inside an approved subbase to Q7800A1003/U or Q7800A1005/U
weather-tight enclosure.

Mounting Wiring Subbase

Mounting of Remote Keyboard or Reset
Module See Fig. 1 and 2 for installation dimensions.
1. Mount the subbase in any position except horizontally with
To comply with CE EN60730 for remote mounting of the KDM
the bifurcated contacts pointing down. The standard verti-
and/or Remote Reset Module it is necessary to provide elec-
cal position is recommended. Any other position decreases
trical separation using insulation at least equivalent to double
the maximum ambient temperature rating.
or reinforced insulation.
2. Select a location on a wall, burner or electrical panel. The
This can be accomplished by either: Q7800 can be mounted directly in the control cabinet. Be
1. Optically isolating the communication and/or remote reset sure to allow adequate clearance for servicing, installation,
lines from the control cabinet. access or removal of the relay module, expanded annunci-
ator, KDM, flame amplifier, flame amplifier signal voltage
2. Providing physical separation from the communication
probes, run/test switch, electrical signal voltage probes
and/or remote reset lines using electrical conduit and a
and electrical field connections.

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 RM7890, RM7895 100 Vac

3. For surface mounting, use the back of the subbase as a NOTE: You might receive and error code 101 (via KDM) check
template to mark the four screw locations. Drill the pilot the screws securing the relay to the subbase to check
holes. if they are not tight enough, re-tighten to insure there
4. Securely mount the subbase using four no. 6 screws (not is no gap between the relay and the subbase.
provided).

Fig. 4. Internal block diagram of the RM7890 (see Fig. 6 for detailed wiring instructions).

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Fig. 5. Internal block diagram of the RM7895 Relay Module (see Fig. 7 for detailed wiring instructions).

2. For proper remote wiring of the KDM, refer to the Specifi-

WIRING cations for the 2-line VFD KDM (65-0090), the 4-line LCD
KDM (32-00110), Network Data ControlBus™ Module
WARNING (65-0091) or Extension Cable Assembly (65-0131).
Electrical Shock Hazard or Equipment and Control 3. Disconnect the power supply from the main disconnect
Damage Hazard. before beginning installation to prevent electrical shock
Can cause severe injury, death or equipment and and equipment damage. More than one disconnect may be
control damage. required.
Disconnect the power supply before beginning 4. All wiring must comply with all applicable electrical codes,
installation. ordinances and regulations. Wiring, where required, must
comply with NEC, Class 1 (Line Voltage) wiring.
1. For proper subbase wiring, refer to Fig. 6 and 7.
5. Recommended wire size and type: See Table 6 for the rec-
ommended wire sizes and part numbers.

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 RM7890, RM7895 100 Vac

Fig. 6. Wiring the RM7890 Relay Module.

Table 7. Recommended Wire Sizes and Part Numbers.

Application Recommended Wire Size Recommended Part Numbers

Line voltage terminals 14, 16 or 18 AWG copper conductor, TTW60C, THW75C, THHN90C.
600 volt insulation, moisture-resistant
wiring.
KDM 22 AWG two-wire twisted pair with Belden® 8723 shielded cable (two-wire) or
ground, or five-wire communications Belden® 8771 shielded cable (five-wire) or equivalent.
wire.

Data ControlBus™ Module 22 AWG two-wire twisted pair with Belden® 8723 shielded cable (two-wire) or
ground or five-wire communications Belden® 8771 shielded cable (five-wire) or equivalent.
wire.

Remote Reset Module 22 AWG two-wire twisted pair, —

insulated for low voltage.
Modbus™ Module 22 AWG two-wire twisted pair with Belden® 8723 shielded cable or equivalent.
ground.
13 Vdc full-wave rectified 18 AWG wire insulated for voltages and TTW60C, THW75C, THHN90C.
transformer power input. temperatures for given application.
The KDM, and (for remote mounting or communications) Data modules on the closest and farthest end of the daisy chain
ControlBus™ Module or Modbus™ Module must be wired in a configuration string require a 120 ohm (1/4 watt minimum)
daisy chain configuration, resistor termination across terminals 1 and 2 of the electrical
(1(a)-1(a), 2(b)-2(b), 3(c)-3(c)). The order of interconnection connectors for connections longer than 100 feet (30 meters).
of all the devices listed above is not important. Be aware that

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Fig. 7. Wiring the RM7895E,F Relay Module.

6. For recommended grounding practices, see Table 8.

Table 8. Recommended Grounding Practices.

Ground Type Recommended Practice

Earth ground (subbase and relay module). 1. Use to provide a connection between the subbase and the control
panel of the equipment. Earth ground must be capable of conducting
enough current to blow the 15A fuse (or breaker) in the event of an in-
ternal short circuit.
2. Use wide straps or brackets to provide minimum length, maximum
surface area ground conductors. If a lead wire must be used, use 14
AWG copper wire.
3. Make sure that mechanically tighted joints along the ground path are
free of nonconductive coatings and protected against corrosion on
mating surfaces.
Signal ground (KDM, Data ControlBus™ Connect the shield at both ends of the daisy chain to earth ground.
Module, Modbus™ Module
7. Recommended wire routing: b. Data ControlBus™ or Modbus™ Module:
a. For flame detector leadwires: (1) Do not run high voltage ignition transformer wires in
(1) Do not run high voltage ignition transformer wires in the same conduit with, or in close proximity to, the
the same conduit with the flame detection wiring. Data ControlBus Module wiring.
(2) Do not run scanner wires in a conduit with line volt- (2) Do not route Data ControlBus™ or Modbus Module
age circuits. wires in conduit with line voltage circuits.
(3) Enclose scanner wires without armor cable in metal
cable or conduit.
(4) Follow directions given in the flame detector instruc-
tions.

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 RM7890, RM7895 100 Vac

c. KDM: The KDM is powered from a low voltage, ener- a. Allow an additional two inches (51 mm) below the relay
gy-limited source, so it can be mounted outside of the module for the flame amplifier mounting.
control panel if it is protected from mechanical damage. b. Allow an optional three-inch (76 mm) minimum to both
NOTE: Use a separate 13 Vdc power supply any time more sides of the relay module for electrical signal voltage
than two Data ControlBus™ Modules or KDM are probes.
used or when placed more than 100 feet (30 meters) 3. Make sure subbase wiring does not project beyond the
from the relay module. terminal blocks. Tuck in wiring against the back of the sub-
d. Remote Reset Module: base so it does not interfere with the knife blade terminals
or bifurcated contacts.
(1) Do not run high voltage ignition transformer wires
in the same conduit with the Remote Reset Module IMPORTANT
wiring. The relay module must be installed with a plug-in motion
(2) Do not route Remote Reset Module wires in conduit rather than a hinge action.
with line voltage circuits. 4. Mount the relay module by aligning the four L-shaped cor-
8. Maximum wire lengths: ner guides and knife blade terminals with the bifurcated
a. For the relay module, the maximum length of leadwire contacts on the wiring subbase and securely tightening
to the control terminal input is 300 feet (91 meters). the two screws without deforming the plastic.
b. For the flame detector leadwires, the maximum flame
sensor leadwire length is limited by the flame signal Dust Cover Mounting
strength.
c. Remote Reset Module leadwires: The maximum length 1. Align the interlocking ears of the dust cover with the two
of wire is 1000 feet (305 meters) to a Remote Reset mating slots in the relay module, see Fig. 10.
Module pushbutton. 2. Insert the two interlocking ears into the two mating slots,
d. Data ControlBus™ or Modbus™ Module: The maximum and with a hinge action, push on the upper corners of the
cable length depends on the number of system modules dust cover to secure it to the relay module.
connected, the noise conditions, and the cable used. 3. Be sure the dust cover is firmly in place.
The maximum length of all interconnecting wires is
1000 feet (305 meters).
Installing ST7800 Purge Card (RM7895 Only)
9. Make sure loads do not exceed the terminal ratings. Refer
to the label on the relay module or to the ratings in the 1. Remove the dust cover, KDM, Data ControlBus™ Module, or
Specifications section. See Table 1. extension cable assembly.
10. Check the power supply circuit to be sure the voltage and 2. Remove the current ST7800 Purge Card from the relay
frequency tolerance match those of the relay module. A module by pulling upward on the plastic support cover.
separate power supply circuit can be required for the relay See Fig. 11.
module with the required disconnect means and overload 3. Make sure that the ST7800 Purge Card selected has the
protection added. desired purge timing.
11. Check all wiring circuits and complete the Static Checkout, 4. Insert the ST7800 Purge Card into the opening of the relay
see Table 8, before installing the relay module on the wir- module purge card compartment. See Fig. 11.
ing subbase.
12. Install all electrical connectors. Installing Plug-In Flame Signal Amplifier
13. Restore power to the panel. 1. Disconnect the power supply before beginning installation
to prevent electrical shock and equipment damage. More
ASSEMBLY than one disconnect can be involved.
2. Align the amplifier circuit board edge connector with the
Mounting RM7890; RM7895 keyed receptacle on the relay module. Verify that the am-
plifier nameplate faces away from the relay module. See
NOTE: For installation dimensions, see Fig. 1 or 2. Fig. 12.
3. Push in the amplifier until the circuit board is fully inserted
Relay Module Mounting into the receptacle and then push the amplifier toward the
relay module retaining clasp.
1. Mount the relay module vertically, see Fig. 8 or 9, or mount
4. Verify the amplifier is firmly in place.
horizontally with the knife blade terminals pointing down-
ward. When mounting on the Q7800A Wiring Subbase, the 5. Perform all required checkout tests.
relay module must be in an electrical enclosure.
2. Select the location in the electrical enclosure. Be sure to
Installing Flame Detector
allow adequate clearance for servicing, installation and NOTE: See Table 5 for the flame detection system available
removal of the relay module, dust cover, flame amplifier, for use with the relay module. Make sure the correct
flame amplifier signal voltage probes, electrical signal volt- combination of amplifier and flame detector is used.
age probes and electrical connections.

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RM7890, RM7895 100 Vac

Proper flame detector installation is the basis of a safe and

reliable flame safeguard installation. Refer to the instructions
packed with the flame detector and the equipment manufac-
turer instructions.
Keep the flame signal leadwires as short as possible from the
flame detector to the wiring subbase. Capacitance increas-
es with leadwire length, reducing the signal strength. The
maximum permissible leadwire length depends on the type
of flame detector, leadwire and conduit. The ultimate limiting
factor in the flame detector leadwire is the flame signal. See
Table 10.

Fig. 10. Dust cover mounting.

Fig. 8. Electrical panel installation.

Fig. 11. ST7800 Purge Card installation (RM7895 only).

Fig. 9. Wall or burner installation.

Fig. 12. Flame signal amplifier mounting.

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 RM7890, RM7895 100 Vac

Fig. 13. RM7890 sequence.

Fig. 14. RM7895 sequence.

OPERATION
Sequence of Operation
The relay modules have operating sequences as shown in Fig.
13 through 15.

INITIATE
The relay module enters the INITIATE sequence if the relay
module verifies voltage fluctuations of +10%/-15% or fre-
quency fluctuations of ±10% during any part of the operating
sequence. The INITIATE sequence lasts for ten seconds un-
less the voltage or frequency tolerances are not met. When
the tolerances are not met, a hold condition is initiated and
displayed on the optional KDM for at least five seconds. When
Fig. 15. Sequence status LED.
the tolerances are met, the INITIATE sequence restarts. If the

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RM7890, RM7895 100 Vac

condition is not corrected and the hold condition exists for 2. Flame must be proven by the end of the 4- or
four minutes, the relay module locks out. Causes for hold con- 10-second PFEP to allow the sequence to continue. If
ditions in the INITIATE sequence are: flame is not proven by the end of PFEP, a safety shutdown
occurs. For the RM7890 only: if the flame is established
1. Ac line dropout is detected.
within the PFEP, the system immediately goes to the RUN
2. Ac line frequency error. state.
3. Ac line noise occurred that prevents a sufficient reading of 3. With flame proven (RM7895 reaches the end of the PFEP),
the line voltage inputs. the ignition, terminal 10, is de-energized and the main
4. Brownout occurred caused by a low line voltage. valve, terminal 9, is energized.
The INITIATE sequence also delays the burner motor starter Run
from being energized and de-energized from an intermittent
ac line input or control input. The relay module is now in RUN and remains in RUN until ter-
minal 6, the controller input, opens, indicating that the call for
heat demand is satisfied or that a limit has opened.
STANDBY
The relay module is ready to start an operating sequence Selectable Site-Configurable Jumpers
when the operating control input determines a call for heat is
The RM7890 has two site-configurable jumper options and
present. The burner switch, limits, operating limit control and
the RM7895 has three. See Fig. 16 and Tables 8 and 9. The
all microcomputer monitored circuits must be in the correct
site-configurable jumpers should be clipped with side cutters
state for the relay module to continue into the SAFE-START
and the resistors removed from the relay module.
CHECK (RM7890) or the PREPURGE (RM7895) sequence.
SERVICE NOTE: For RM7890 when using a 3-second am-
Normal Startup plifier, clip and remove site-configurable
jumper JR2. If not removed, an F46 Lock-
Safe-Start Check out occurs.

The RM7890, RM7895 verify that a flame does not exist and IMPORTANT
proceeds into the Ignition Trial. If a flame is present, the relay Clipping jumpers after 200 hours of operation will result in a
module recycles to the STANDBY period. If the critical loads hard lockout (Fault Code 110).
are not in the correct state, a safety shutdown occurs.

Prepurge (RM7895)
The RM7895 provides a selectable PREPURGE timing from
two seconds to thirty minutes (using the ST7800 Plug-in
Purge Timer) with power applied and the RM7895 operating
control indicating a call for heat.
1. Airflow Interlock, burner switch and all microcomputer
monitored circuits must be in the correct operating state.
2. The blower motor output, terminal 4, is powered to start
the PREPURGE sequence.
3. The Airflow Interlock input must close ten seconds into
PREPURGE or within the specified purge card timing; oth-
erwise, a recycle to the beginning of PREPURGE or lockout
occurs depending on how the airflow switch selectable
jumper is configured.
Ignition Trials
Pilot Flame Establishing Period (PFEP):
1. The pilot valve and ignition transformer, terminals 8 and Fig. 16. Selectable site-configurable jumpers (RM7895
10, are energized. The relay module has an intermittent pi- shown).
lot valve, terminal 8.

Table 9. Site-Configurable Jumper Options (RM7890).

Jumper Number Description Intact Clipped

JR1 Pilot Flame Establishing Period 10 seconds 4 seconds
JR2 Flame Failure Action Relighta Lockout
aThe Relight feature (JR2) requires a 0.8 second FFRT flame amplifier.

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Table 10. Site-Configurable Jumper Options (RM7895).

Jumper Number Description Intact Clipped

JR1 Pilot Flame Establishing Period 10 seconds 4 seconds
JR2 Flame Failure Action Recycle Lockout
JR3 Airflow Switch (ILK) Failure Recycle Lockout

STATIC CHECKOUT Equipment Recommended

1. Voltmeter (one megohm/volt minimum sensitivity), set on
WARNING the 0 to 300 Vac scale.
Electrical Shock Hazard. 2. Two jumper wires, no. 14 wire, insulated, 12 in. (305
Can cause severe injury, death or property damage. mm) long with insulated alligator clips at both ends.
Open the master switch before installing or removing a An ­ammeter can replace one of the jumper wires when
jumper on the wiring subbase. ­checking operation of terminals 8, 9, or 10. Verify amp
draw to the device nameplate.
1. Use extreme care when testing the system because line
voltage is present on most terminal connections when General Instructions
power is on.
1. Perform all applicable tests listed in Static Checkout,
2. Before continuing to the next test, be sure to remove the
­Tables 11 and 12, in the order listed.
test jumper(s) used in the previous test.
2. Make sure that all manual fuel shutoff valves are closed.
3. Replace all limits and interlocks not operating properly. Do
not bypass limits and interlocks. 3. Perform only those tests designated for the specific relay
module model being tested.
4. Close all manual fuel shutoff valves before starting the
tests. 4. Raise the setpoint of the operating controller to simulate a
call for heat.
After checking all wiring, perform this checkout before in-
stalling the relay module on the wiring subbase. These tests 5. For each test, open the master switch and install the jumper
verify that the Q7800 Wiring Subbase is wired correctly and wire(s) between the subbase wiring terminals listed in the
that the external controllers, limits, interlocks, actuators, Test Jumpers column of Table 11 or Table 12.
valves, transformers, motors and other devices are operating 6. Close the master switch before observing operation.
­properly. 7. Read the voltage between the subbase wiring terminals
listed in the Voltmeter column of Table 11 or 12.
CAUTION 8. If there is no voltage or the operation is abnormal, check
Equipment Damage Hazard. the circuits and external devices as described in the last
High voltage dielectric test can cause equipment column.
damage. 9. Check all wiring for correct connections, tight terminal
Do not perform dielectric test with the relay module screws, correct wire size, and proper wiring techniques. Re-
installed. Internal surge protectors break down and place all damaged or incorrectly sized wires.
conduct a current, causing dielectric test failure and 10. Replace faulty controllers, limits, interlocks, actuators,
destruction of the internal lightning and high current valves, transformers, motors and other devices as required.
protection.
11. Obtain normal operation for each required test before con-
tinuing the checkout.
12. After completing each test, be sure to remove the test
jumper(s).

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Table 11. RM7890 Static Checkout.

Test Number Test Voltmeter Normal Operation If Operation is Abnormal, Check the Items
Jumpers Listed Below

WARNING
Explosion Hazard.
Can cause severe injury, death or property damage.
Make sure that all manual fuel shutoff valves are closed.

IMPORTANT
Low fuel pressure limits, if used, could be open. Bypass them with jumpers for the remaining static tests, if required.
1 None 3 to L2 Line voltage at terminal 3. 1. Master Switch.
2. Power connected to the Master Switch.
3. Overload protection (fuse, circuit breaker)
has not opened the power line.
2 None 6 to L2 Line voltage at terminal 6. 1. Limits.
2. Burner controller.
3 3 to 10a — Ignition spark (if ignition 1. Watch for spark or listen for buzz.
transformer is connected to a. Ignition electrodes are clean.
terminal 10). b. Ignition transformer is okay.
4 3 to 8a — Ignition spark (if ignition 1. Watch for spark or listen for buzz.
transformer is connected to a. Ignition electrodes are clean.
terminal 8). b. Ignition transformer is okay.
Automatic pilot valve opens (if
connected to terminal 8). 2. List for click or feel head of valve for acti-
vation.
Refer to wiring diagram of system a. Actuator, if used.
being tested.
b. Pilot valve.
5 3 to 9a — Automatic fuel valve(s) opens. If Same as test number 4. If using direct spark
using direct spark ignition, check ignition, check the first stage fuel valve(s)
the first stage fuel valve(s) instead of the pilot valve.
instead of the pilot valve.
6 3 to 4 — Alarm, if used, turns on. Alarm.
Final
CAUTION
Equipment Damage Hazard.
Incorrect wiring can damage equipment.
After completing these tests, open the Master Switch and remove all test jumpers from the subbase
terminals. Also remove the bypass jumpers from the low fuel pressure limits (if used).
a Use an ammeter in place of the jumper wire to verify current draw of the terminal loads. Do not exceed ratings shown in Tables 3 and 4.

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Table 12. RM7895 Static Checkout.

If Operation is Abnormal, Check the Items

Test Number Test Jumpers Voltmeter Normal Operation Listed Below

WARNING
Explosion Hazard.
Can cause severe injury, death or property damage.
Make sure that all manual fuel shutoff valves are closed.

IMPORTANT
Low pressure fuel limits, if used, could be open. Bypass them with jumpers for the remaining static tests, if required.
1 None 5 to L2 Line voltage at terminal 3. 1. Master Switch.
2. Power connected to the Master Switch.
3. Overload protection (fuse, circuit breaker)
has not opened the power line.
2 None 6 to L2 Line voltage at terminal 6. 1. Limits.
2. Burner controller.
3 4 to 5 7 to L2 Burner motor (fan or blower) 1. Burner motor circuit.
starts. a. Manual switch of burner motor.
Line voltage at terminal 7 within b. Burner motor power supply, overload
10 seconds. protection and starter.
c. Burner motor.
4 5 to 10a — Ignition spark (if ignition 1. Watch for spark or listen for buzz.
transformer is connected to a. Ignition electrodes are clean.
terminal 10). b. Ignition transformer is okay.
5 5 to 8a — Ignition spark (if ignition 1. Watch for spark or listen for buzz.
transformer is connected to a. Ignition electrodes are clean.
terminal 8). b. Ignition transformer is okay.
Automatic pilot valve opens (if
connected to terminal 8). 2. List for click or feel head of valve for acti-
vation.
Refer to wiring diagram of a. Actuator, if used.
system being tested.
b. Pilot valve.

6 5 to 9a — Automatic fuel valve(s) opens. If 3. Same as test number 5. If using direct

using direct spark ignition, spark ignition, check the first stage fuel
check the first stage fuel valve(s) instead of the pilot valve.
valve(s) instead of the pilot
valve.
7 5 to 3 — Alarm, if used, turns on. Alarm.
Final
CAUTION
Equipment Damage Hazard.
Incorrect wiring can damage equipment.
After completing these tests, open the Master Switch and remove all test jumpers from the subbase
terminals. Also remove the bypass jumpers from the low fuel pressure limits (if used).
a Use an ammeter in place of the jumper wire to verify current draw of the terminal loads. Do not exceed ratings shown in Tables 3 and 4.

Limit the trial for pilot to ten seconds, and limit the attempt
CHECKOUT to light the main burner to two seconds from the time the fuel
reaches the burner nozzle. Do not exceed the nominal ligh-
WARNING toff time specified by the equipment manufacturer. Close the
Explosion Hazard. manual fuel shutoff valve(s) if the flame is not burning at the
Can cause severe injury, death or property damage. end of the specified time.
Do not allow fuel to accumulate in the combustion
chamber. If fuel is allowed to enter the chamber for
longer than a few seconds, an explosive mixture could
result.

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RM7890, RM7895 100 Vac

3. Initial lightoff check for proved pilot, all installations using

WARNING a pilot.
Explosion Hazard. 4. Initial lightoff check for direct spark ignition (DSI) of oil, all
Can cause severe injury, death or property damage. burners using DSI.
Use extreme care while testing the system. Line voltage 5. Pilot turndown test, all installations using a pilot.
is present on most terminal connections when power is 6. Hot refractory hold-in test, all installations.
on.
7. Ignition interference test, all installations using flame rods.
1. Open the master switch before removing or installing the 8. Flame signal with hot combustion chamber, all installa-
relay module. tions.
2. Make sure all manual fuel shutoff valve(s) are closed be- 9. Safety shutdown tests, all installations.
fore starting the initial lightoff check and the Pilot Turn- See Fig. 14 for location of component parts and see Fig. 5
down tests. or 6 or Q7800 Specifications, form 65-0084, for terminal
3. Do not put the system into service until you have satisfac- ­locations.
torily completed all applicable tests in this section and any
others required by the equipment manufacturer. Preliminary Inspection
When performing the following inspections, check to verify:
CAUTION 1. Wiring connections are correct and all terminal screws are
Equipment Damage Hazard. tight.
Use of improper equipment will cause operational 2. Flame detector is clean, installed and positioned properly.
failure. (Check the applicable installation instructions.)
Do not replace the RM7890, RM7895 Relay Module with 3. Correct combination of amplifier and flame detector is
a lower or higher functioning relay module until you used. See Table 4.
have made the necessary wiring changes or the burner 4. Plug-in amplifier is securely in place.
will not sequence.
5. Burner is completely installed and ready to fire. (Consult
equipment manufacturer instructions.)
IMPORTANT
6. Fuel lines are purged of air.
1. If the system fails to function properly, refer to 7800
SERIES Relay Modules Checkout and Troubleshooting, 7. Combustion chamber and flues are clear of fuel and fuel
form 65-0229. vapors.
2. Repeat all required CHECKOUT tests after all adjust- 8. Power is connected to the system disconnect switch (mas-
ments are made. All tests must be satisfied with the ter switch).
flame detector in its final position. 9. Lockout switch is reset (push in reset pushbutton) only if
the relay module is powered; see Fig. 14.
Equipment Recommended 10. System is in the STANDBY condition and POWER LED is
energized.
Volt ohmmeter (one megohm/volt minimum sensitivity):
11. All limits and interlocks are reset.
a. 0 to 300 Vac range.
b. 0 to 6000 ohms range.
Flame Signal Measurement
c. 0 to 10 Vdc range.
Measure the flame signal at the appropriate times defined in
Checkout Summary the following checkout tests. Read the flame signal volts dc at
the flame amplifier test jacks + and - (Com). See Fig. 17 and
1. Preliminary inspection, all installations. Table 13.
2. Flame signal measurement, all installations.

Table 13. Flame Signal.

Minimum Acceptable Steady dc Voltagea Maximum Expected dc Voltage

5.0 Vdc at the KDM
1.25 Vdc or
5.0 Vdc at a one megohm per volt meter.
a This minimum or a stronger signal should be easily obtained if the detector is installed correctly and positioned to properly sense the flame.
This voltage must be obtained before completing checkout.

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 RM7890, RM7895 100 Vac

Initial Lightoff Check for Proved Pilot

Perform this check immediately following the preliminary in-
spection on all installations that use a pilot:
NOTE: Low fuel pressure limits, if used, could be open; if so,
bypass with jumpers during this check.
1. Open the master switch.
2. Make sure the manual main fuel shutoff valve(s) is closed.
3. Open the manual pilot shutoff valve. If the pilot takeoff is
downstream from the manual main fuel shutoff valve(s),
slightly open the manual main valve to supply pilot gas
flow. Make sure the main fuel is shut off just upstream
from the burner inlet, or disconnect power from the auto-
matic main fuel valve(s).
4. Close the master switch and start the system with a call
for heat by raising the setpoint of the operating controller,
see Fig. 15 or the relay module sequence. The sequence
Fig. 17. Flame signal measurement. should start the ten-second INITIATE sequence.
5. Let the sequence advance through STANDBY and SAFE-
1. Use a one megohm per volt meter with a 0 to 10 Vdc capa- START CHECK (PREPURGE in the RM7895). Ignition spark
bility. should occur and the pilot should light. If the pilot ignites,
2. Set the one megohm per volt meter to the 0 to 10 Vdc the FLAME LED will be lighted. Proceed to step 8.
range. 6. If the pilot flame is not established in 15 or 30 seconds,
3. Insert the positive (red) probe into the + jack of the flame safety shutdown occurs. Let the sequence complete its
amplifier and the negative (black) probe into the - (Com) cycle. Consult the equipment operating manual for further
jack of the flame amplifier (see Fig. 17). information.
4. Allow a few seconds for the meter reading to stabilize. 7. Push the reset pushbutton and let the system recycle once.
5. If using AMPLI-CHECK TM or shutter check amplifiers, read If the pilot still does not ignite, make the following ignition/
the average stable voltage, disregarding the peaks and val- pilot adjustments.
leys caused by the self-checking operation. a. Open the master switch and remove the relay module
from the subbase.
6. The meter reading must be as specified in Table 10 after all
b. On the subbase, jumper terminal 3 on the RM7890
tests are made and all adjustments are made.
(terminal 5 on the RM7895) to ignition terminal 8 or 10,
As an option, check the flame signal by using the optional refer to the appropriate wiring diagram (Fig. 4 through
KDM. 7) to determine the proper terminal. Disconnect the
If the signal is unstable or less than the minimum acceptable leadwire to the pilot valve if it is connected to the same
voltage, check the flame detector installation and circuitry. terminal.
c. Close the master switch to energize only the ignition
1. Check the supply voltages at terminals 3 (L1) and L2 (N) transformer.
for the RM7890 and terminals 5 (L1) and L2 (N) for the d. If the ignition spark is not strong and continuous, open
RM7895. Make sure the master switch is closed, connec- the master switch and adjust the ignition electrode
tions are correct and the power supply is of the correct spark gap setting to the manufacturer recommenda-
voltage, frequency and is sinusoidal. tions.
2. Check the detector wiring for defects: e. Make sure the ignition electrodes are clean.
a. Deteriorated wiring. f. Close the master switch and observe the spark.
b. Incorrect connections. g. After a continuous spark is obtained, open the master
c. Leakage paths caused by moisture, soot or ­accumulated switch and add a jumper on the subbase from terminal 3
dirt. (L1) (RM7890) or terminal 5 (L1) (RM7895) to the pilot
d. Open circuits. terminal 8. Reconnect the leadwire from the pilot valve if
e. Short circuits. it was disconnected in step b.
f. Wrong type of wire. h. Close the master switch to energize both the ignition
3. For a flame rod, make sure: transformer and the pilot valve.
a. Flame rod is properly located in the flame. i. If the pilot does not ignite and if the ignition spark is still
b. Ground area is large enough. continuous, adjust the pressure regulator until a pilot is
c. Temperature at the flame rod insulator is no greater established.
than 500°F (260°C). j. When the pilot ignites properly and stays ignited, open
the master switch and remove the subbase jumper(s)
4. Make sure that the flame adjustment is not too lean. from terminals 3 to 8 or 3 to 10 (terminals 5 to 8 or 5 to
5. If necessary, reposition the flame detector. 10 on the RM7895).
k. Check for adequate bleeding of the fuel line.
l. Reinstall the relay module on the subbase, close the
master switch and return to step 4.

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8. When the pilot ignites, measure the flame signal. If the NOTE: Upon completing these tests, open the master switch
pilot flame signal is unsteady or approaching the 1.25 and remove all test jumpers from the subbase termi-
Vdc minimum value, adjust the pilot flame size or detector nals, limits/controls or switches.
­position to provide a maximum and steady flame signal.
9. Recycle the system to recheck lightoff and pilot flame Initial Lightoff Check for Direct Spark
­signal.
Ignition (DSI)
10. When the RUN period (MAIN IGN period for the RM7895)
is displayed by the MAIN LED, make sure the automatic Use this check for gas and oil burners that do not use a pilot
main fuel valve is open; then smoothly open the ­manual immediately following the preliminary inspection. Refer to the
main fuel shutoff valve(s) and watch for main burner appropriate sample block diagram of field wiring for the igni-
flame ignition. When the main burner flame is established, tion transformer and fuel valve(s) hookup.
­p­roceed to step 17. NOTE: Low fuel pressure limits, if used, could be open; if so,
11. If the main burner flame is not established within five bypass them with jumpers during this check.
seconds or the normal lightoff time specified by the equip-
ment manufacturer, close the manual main fuel shutoff 1. Open the master switch.
valve(s). 2. Complete the normal checkout of the fuel supply and
12. Recycle the system to recheck lightoff and pilot flame sig- equipment as recommended by the equipment manufac-
nal. turer.
13. Let the relay module recycle to the RUN period (MAIN IGN 3. Close all manual main fuel shutoff valve(s). Check that the
period for the R7895). Smoothly open the manual fuel automatic fuel valve(s) are closed. Make sure fuel is not
shutoff valve(s) and try lightoff again. (The first attempt entering the combustion chamber.
may have been required to purge the lines and bring suffi- 4. Close the master switch and start the system with a call for
cient fuel to the burner.) heat by raising the setpoint of the operating controller; see
14. If the main burner flame is not established within five Fig. 15 or the relay module operating sequences. The pri-
seconds or the normal lightoff time specified by the mary sequence should start with the 10-second INITIATE
­equipment manufacturer, close the manual fuel shutoff sequence.
valve(s). Check all burner adjustments. 5. Let the sequence advance through STANDBY and SAFE-
15. If the main burner flame is not established after two START CHECK for the RM7890 (PREPURGE for the
­attempts: RM7895) to Ignition Trial. Ignition spark should occur.
a. Check for improper pilot size. ­Listen for the click of the first stage fuel solenoid valve(s).
b. Check for excess combustion air. 6. Let the program sequence complete its cycle.
c. Check for adequate fuel flow. 7. Open the manual fuel shutoff valve(s).
d. Check for proper gas supply pressure.
8. Push the reset button and recycle the program sequence
e. Check for proper valve operation.
through STANDBY and SAFE-START CHECK for the
f. Check for proper pilot flame positioning.
RM7890 (PREPURGE for the RM7895).
16. Repeat steps 11 through 15 to establish the main burner
9. Watch for the FLAME LED to help determine when the first
flame, then proceed to step 17.
stage burner flame is established. If it is established, go to
17. With the sequence in RUN, make burner adjustments for step 15.
flame stability and BTU input rating.
10. If the first stage burner flame is not established within four
18. Shut down the system by opening the burner switch or by seconds, or within the normal lightoff time specified by the
lowering the setpoint of the operating controller. Make equipment manufacturer, close the manual fuel shutoff
sure the main flame goes out. There may be a delay due valve(s) and open the master switch.
to gas trapped between the valve(s) and the burner. Make
11. Check all burner adjustments.
sure all automatic fuel valve(s) close.
12. Wait about three minutes. Close the master switch, open
19. Restart the system by closing the burner switch and/or
the manual fuel shutoff valve(s), and try again to light off
raising the setpoint of the operating controller. Observe
the burner. The first attempt may have been required to
that the pilot is established during PILOT IGN and the
purge the lines and bring sufficient fuel to the burner.
main burner flame is established during RUN (MAIN IGN
for RM7895) within the normal lightoff time. 13. If the first stage burner flame is not established within four
seconds or within the normal lightoff time specified by the
20. Measure the flame signal. Continue to check for the proper
equipment manufacturer, close the manual fuel shutoff
signal, see Table 10, through the RUN period.
valve(s) and open the master switch.
21. Run the burner through another sequence, observing the
14. If necessary, repeat steps 8 through 13 to establish the
flame signal for:
first stage burner flame. Then proceed to step 15.
a. Pilot flame alone (unless using direct spark ignition).
b. Pilot and main flame together. Also observe the time it 15. When the first stage burner flame is established, the se-
takes to light the main flame. Ignition of the main flame quence will advance to RUN. Make burner adjustments for
should be smooth. flame stability and input rating. If a second stage is used,
proceed to step 18.
22. Return the system to normal operation.
16. Shut down the system by opening the burner switch or by
23. Make sure all readings are in the required ranges before
lowering the setpoint of the operating controller. Make
proceeding.
sure the burner flame goes out and make sure all automat-
ic fuel valves close.
32-00216-01 22
 RM7890, RM7895 100 Vac

17. If used, remove the bypass jumpers from the low fuel pres- NITION or the RM7895 to recycle through PREPURGE.
sure limit and subbase. If the Flame Failure Action jumper is clipped: push the
18. If a second stage is used, make sure the automatic second reset pushbutton and allow the RM7890D to recycle to
stage fuel valve(s) opened, and check the lightoff as fol- PILOT IGNITION or the RM7895E,F to recycle through
lows (otherwise proceed to step 19): PREPURGE.
a. Open the manual second stage fuel valve(s). b. As the control attempts to relight the pilot, increase the
b. Restart the system by raising the setpoint of the operat- pilot pressure immediately until the FLAME LED comes
ing controller. on, and then turn it down slowly to obtain a pressure
c. When the first stage burner flame is established, watch reading just above the dropout point or until the flame
for the automatic second stage fuel valve(s) top open. signal increases to approximately 1.25 Vdc. This step
Observe that the second stage lights off properly. must be completed within 4 or 10 seconds, depending
d. Make burner adjustments for flame stability and input on the selected PFEP, or lockout occurs.
rating. c. Turn the pilot back down slightly but not enough to
e. Shut down the system by lowering the setpoint of the cause the FLAME LED to go out. (Keep the pilot gas
operating controller. Make sure the burner flame goes pressure just above the reading noted in step 6 above.)
out and that all automatic fuel valve(s) close. NOTE: Step d requires two people, one to open the manual
19. Restart the system by closing the burner switch and/or main fuel valve(s) and one to watch for ignition.
raising the setpoint of the operating controller. Observe d. With the sequence in the normal burner run mode, make
that the burner flame is established during PILOT IGN, sure the automatic fuel valve(s) is open. Smoothly open
within the normal lightoff time specified by the equipment the manual main fuel shutoff valve(s) and watch for
manufacturer. main burner lightoff.
20. Measure the flame signal. Continue to check for the proper e. If the main flame is not established within five seconds
signal, see Table 10, through the RUN period. Any pulsat- or the normal lightoff period specified by the burn-
ing or unsteady readings will require further attention. er manufacturer, close the manual main fuel shutoff
valve(s) and open the master switch. Then return to step
21. Make sure all readings are within the required ranges be-
6a. If the burner flame is established in the normal ligh-
fore proceeding.
toff period, proceed to step 10.
NOTE: Upon completing these tests, open the master switch
7. Recycle the burner and let the sequence advance to the
and remove all test jumpers from the subbase termi-
PILOT IGN period for the RM7890; advance to the PRE-
nals, limits/controls or switches.
PURGE period for the RM7895.
22. Return the system to normal operation. 8. Increase the pilot flame size by increasing its fuel flow until
a smooth main flame is accomplished.
Pilot Turndown Test (All Installations 9. Reposition the flame rod until the pilot flame signal volt-
Using a Pilot) age is approximately 1.25 to 1.50 Vdc.
Perform this check on all installations that use a pilot. The 10. When the main burner lights reliably with the pilot at turn-
purpose of this test is to verify that the main burner can be lit down, disconnect the manometer (or pressure gauge) and
by the smallest pilot flame that will hold in the flame amplifier turn up the pilot gas flow to the level recommended by the
and energize the FLAME LED. If using AMPLI-CHECK™ and equipment manufacturer.
one megohm per volt meter, the flame signal will fluctuate ev- 11. If used, remove the bypass jumpers from the subbase ter-
ery time the amplifier does a self check. minals, limits/control or switches.
NOTE: Low fuel pressure limits, if used, could be open. If so, 12. Run the system through another cycle to check for normal
bypass them with jumpers during this test. operation.
13. Return the system to normal operation.
1. Open the master switch.
2. Close the manual main fuel shutoff valve(s). Ignition Interference Test (All Flame Rods)
3. Connect a manometer (or pressure gauge) to measure pilot
gas pressure during the turndown test. Test to be sure that a false signal from a spark ignition system
is not superimposed on the flame signal.
4. Open the manual pilot shutoff valve(s).
5. Close the master switch and start the system with a call for Ignition interference can subtract from (decrease) or add to
heat by raising the setpoint of the operating controller. The (increase) the flame signal. If it decreases the flame signal
primary sequence should start and PILOT IGNITION for enough, it causes a safety shutdown. If it increases the flame
the RM7890 (PREPURGE for the RM7895) should begin. signal, it can cause the FLAME LED to come on when the true
flame signal is below the minimum acceptable value.
6. After the sequence has entered the normal burner run pe-
riod, turn the pilot gas pressure down very slowly, reading Start the burner and measure the flame signal with both igni-
the manometer (or gauge) as the pressure drops. Stop im- tion and pilot (or main burner) on, and then with only the pilot
mediately when the FLAME LED goes out. Note the pres- (or main burner) on. Any significant difference (greater than
sure at this point. 0.5 Vdc) indicates ignition interference.
NOTE: If there is no flame present for the selected Flame
Failure Response Test (FFRT), the relay module will
lock out.
a. If the Flame Failure Action jumper (see Table 6 or 7, JR2)
is not clipped: allow the RM7890 to recycle to PILOT IG-
23 32-00216-01
RM7890, RM7895 100 Vac

To Eliminate Ignition Interference 5. Observe loss of flame during RUN (if Flame Failure Action
configuration jumper, JR2, is selected for Lockout, see Ta-
1. Make sure there is enough ground area. bles 6 and 7).
2. Be sure the ignition electrode and the flame rod are on op- a. Open the main fuel manual shutoff valve(s) and open
posite sides of the ground area. the manual pilot shutoff valve(s).
3. Check for correct spacing on the ignition electrode: b. Depress the reset pushbutton.
c. Start the system. Startup should be normal and the
4. 6,000V systems 1/16 in. to 3/32 in. (1.6 mm to 2.4 mm). main burner should light normally.
5. 10,000V systems 1/8 in. (3.2 mm). d. After the sequence is in the normal RUN period for at
6. Make sure the leadwires from the flame rod and ignition least ten seconds with the main burner firing, close the
electrode are not too close together. manual main and pilot fuel shutoff valve(s) to extin-
guish the main burner flame.
7. Replace any deteriorated leadwires.
e. The flame signal drops below 1.25 Vdc within 0.8 or 3
seconds (depending upon the FFRT of the amplifier) af-
Flame Signal with Hot Combustion Chamber ter the main flame goes out.
(All Installations) f. Safety shutdown occurs.
1. After all initial start-up tests and burner adjustments are IMPORTANT
completed, operate the burner until the combustion cham- 1. If the relay module fails to shut down on any of these
ber is at the maximum expected temperature. tests, take corrective action (refer to the Troubleshooting
2. Observe the equipment manufacturer warmup instruc- section or RM7890, RM7895 diagnostics) and return to
tions. the beginning of all checkout tests.
3. Recycle the burner under these hot conditions and mea- 2. When all Checkout tests are completed, reset all switches
sure the flame signal. to original states.
4. Check the pilot alone for non-DSI (Direct Spark Ignition)
applications or the main burner flame for DSI applications. TROUBLESHOOTING
5. Check the FFRT of the flame amplifier.
6. Lower the setpoint of the operating controller and observe RM7890, RM7895 System Diagnostics
the time it takes for the burner flame to go out. This should
be within 0.8 or 3 seconds maximum, depending on the Troubleshooting control system equipment failures is easier
amplifier selected. with the relay module self-diagnostics and first-out annuncia-
7. If the flame signal is too low or unsteady, check the flame tion through the optional KDM. In addition to an isolated spdt
detector temperature. alarm relay (audible annunciation), the relay module provides
visual annunciation by displaying the ALARM LED.
8. Relocate the detector if the temperature is too high.
9. If the response time is still too slow, replace the Plug-in Self-diagnostics of the relay module enable it to detect and
Flame Signal Amplifier. annunciate both external and internal system problems. Ex-
ternal faults such as flame failures and false flame signals are
10. If the detector is relocated or the amplifier is replaced, re- annunciated by a lockout of the relay module that energizes
peat all required Checkout tests. the ALARM LED. Refer to the 7800 SERIES Relay Modules
Checkout and Troubleshooting, form 65-0229 for additional
Safety Shutdown Tests (All Installations) information.
Perform these tests at the end of Checkout, after all other The relay module provides diagnostic information to aid the
tests are completed. If used, the external alarm should turn service mechanic to obtain information when troubleshooting
on. the system. See Table 13.
1. Press the relay module reset pushbutton to restart the The optional KDM displays sequence status messages indi-
system. cating INITIATE, STANDBY, PREPURGE, PILOT IGN, MAIN
2. Open the Airflow Interlock during PREPURGE, PILOT IGN, IGN and RUN. The selectable messages also provide visual in-
MAIN IGN or RUN period (RM7895). dication, current status and historical status of the equipment
a. Safety shutdown occurs if the Airflow ILK Switch Failure such as Flame Signal, Total Cycles, Total Hours, Fault Histo-
configuration jumper (JR3) is clipped (RM7895). ry and Diagnostic Information. With this information most
problems can be diagnosed without extensive trial and error
3. Detect flame 240 seconds after entry to STANDBY.
testing. Information available in the Diagnostic Information
a. Simulate a flame to cause the flame signal voltage level
file includes: Device Type, Device Suffix, Software Revision,
to be at least 1.25 Vdc for 30 seconds after the initial 40
Manufacturing Code, Flame Amplifier Type, Flame Failure
second entry into STANDBY (PREPURGE for RM7895).
Response Time, Selectable Jumper Configuration Status and
b. Safety shutdown occurs.
Terminal Status.
4. Observe that pilot does not ignite.
a. Close the pilot and main fuel manual shutoff valve(s).
b. Depress the reset pushbutton.
c. Start the system.
d. Automatic pilot valve(s) should be energized but the pi-
lot cannot ignite.
e. Safety shutdown will occur.

32-00216-01 24
 RM7890, RM7895 100 Vac

Diagnostic Information Index Historical Information Index

The relay module with the optional KDM can monitor input/ The relay module has nonvolatile memory that allows it to
output terminals and can display the status of the terminal on retain historical information for the six most recent lockouts.
the KDM display (for example, Pilot Valve T8 1<); see S7800 Each of the six lockout files retains the cycle when the fault
Keyboard Display Module specification, form 65-0090. A occurred, the hour of operation when the fault occurred, and
complete terminal description and terminal number are pro- the fault message and burner status when the fault occurred.
vided. The display shows the actual status of the terminal. If The historical information can be viewed by the optional
voltage is detected at the terminal, 1 is displayed; but if volt- S7800 KDM.
age is not present at the terminal, 0 is displayed.

25 32-00216-01
RM7890, RM7895 100 Vac

SERVICE NOTE: SERVICE NOTE:

A lockout condition or restart of a relay module can be accom- Remove the access slot covers on the sides of the Q7800 Wir-
plished by pressing the reset pushbutton on the relay module ing Subbase to check voltages.
or by pressing a remote reset pushbutton wired through an
optional KDM, Data ControlBus™ Module, extension cable
assembly, or remote reset module. A power-up reset module
WARNING
causes an electrical reset of the relay module but does not re- Electrical Shock Hazard.
set a lockout condition. Can cause severe injury, death or property damage.
Replace access slot covers on the Q7800B Wiring
Subbase after performing voltage checks.

NOTE: Normal sequences are in bold type, while abnormal sequences are in regular type.
Table 14. Sequence and Status Hold Information.

Sequence Information
INITIATE The LED indicates the burner status, POWER, which is a stabilization period for the relay module
to check for any fluctuations in ac ling voltage inputs or control input on power-up or during
normal operation. The timing of the INITIATE period is ten seconds before entering STANDBY.
If the relay is in a HOLD status, the following conditions can exist:
INITIATE HOLD: The LED indicates the burner status, POWER, and that the relay module is waiting for excess line
(AC Frequency/Noise) noise to clear up. The burner sequence will not advance into STANDBY until the excess line noise,
which prevents sufficient reading of the line voltage inputs, ceases or a line frequency error is
detected.
INITIATE HOLD: The LED indicates the burner status, POWER, and that ac line power has momentarily dropped
(AC Line Dropout) out. The burner sequence will not advance into STANDBY until the ac line voltage has stabilized
throughout the INITIATE sequence.
INITIATE HOLD: The LED indicates the burner status, POWER, and that line frequency is faster than the expected
(AC Frequency) value. The burner sequence will not advance into STANDBY until the line frequency returns to the
proper value.
INITIATE HOLD: The LED indicates the burner status, POWER, and that low line voltage has occurred. The burner
(Low Line Voltage) sequence will not advance into STANDBY until the line voltage is at a sufficient level for proper
operating parameters.
STANDBY The LED indicates the burner status, POWER. The burner can be placed in STANDBY by opening
the burner switch or if the operating controller indicates its setpoint has been satisfied. If a
demand is present for burner operation, the burner sequence will not advance from STANDBY
until the recycle limit closes.
If the relay module is in a HOLD status, the following conditions could exist:
PURGE (RM7895 only) The LED indicates the burner status, POWER, and that it is the period of time before ignition
during which time the blower motor is running. The timing of the PURGE period is selectable.
PURGE HOLD: F/G (Flame The LED indicates the burner status, POWER and FLAME, and that a flame is detected. The
Detected) (RM7895 Only) burner sequence will not advance through PREPURGE because a flame is detected as being
present. The sequence will hold waiting for the flame signal to clear. If the time exceeds 30
seconds, the relay module will lockout.
PURGE HOLD: T7 (Airflow The LED indicates the burner status, POWER, and that the Airflow Interlock is not closed. The
Interlock) (RM7895 Only) sequence will not advance into ignition until the Airflow Interlock proves closed. If this time
exceeds a 30-second HOLD, the relay module will lockout.
STANDBY HOLD: F/G The LED indicates the burner status, POWER and FLAME, and that a flame is detected. A
(Flame Detected) demand is present for burner operation. The burner sequence will not advance to SAFE START
CHECK (PREPURGE in the RM7895) because a flame is detected as being present. The sequence
will not advance to SAFE START CHECK until the flame signal clears. If the flame signal does not
clear within 40 seconds, the relay module will lockout.

SAFE START CHECK The LED indicates the burner status, POWER, which is the period of time after STANDBY. The
(RM7890 Only) RM7890 is verifying that a flame is not present before the start of Ignition Trials. If a flame is
present, the RM7890 will recycle to STANDBY.

32-00216-01 26
 RM7890, RM7895 100 Vac

Table 14. Sequence and Status Hold Information. (Continued)

Sequence Information
PILOT IGN The LED indicates the burner status, POWER, PILOT, and FLAME, which is the period of time the
relay module permits the pilot valve and ignition to be energized and the pilot flame to be
established.
MAIN IGN The LED indicates the burner status, POWER, PILOT, FLAME, and MAIN, which is the period of
(RM7895 Only) time the RM7895 permits the main valve to be open and the main flame to be tested.
RUN The LED indicates the burner status, POWER, PILOT, FLAME and MAIN, which is the period of
time after the Ignition Trials and before the operating controller setpoint is reached. During this
time, the burner is firing under the control of the operating controller.
RESET/ALARM TEST The LED indicates the burner status, POWER and ALARM. This condition indicates that the reset
pushbutton is pressed. If it is held for more than four seconds, the alarm output is energized. The
alarm output will be de-energized after the reset pushbutton is released.

SAFETY AND SECURITY

Physical device protection
Device shall be accessible to authorized personnel only – In-
stallation on publicly accessible places is not recommended
as this could lead to unwanted and potentially unsafe chang-
es to device (wiring, configuration, etc).
It is recommended to lock the device in an enclosed cabinet
with access allowed only to approved and trained person-
nel. Also, it is strongly advised to keep all the wiring of device
physically secure.
Physical protection of the device is applied via Run/Test
switch label/seal. It is intended to prevent and detect unau-
thorized access.

Modbus & DDL Interface security

Any conducts critical to device functionality (DDL, Modbus
lines etc.) shall be physically protected (installed outside pub-
lic access) since they could be damaged or tampered-with by
unauthorized people, either accidentally or for purpose.
Modbus RS-485 & DDL protocols do not support security fea-
tures. For DDL interface - only DDL devices shall be connect-
ed to the Burner Controller DDL line.

License agreement
Copying and reverse engineering is prohibited by the law.

27 32-00216-01
RM7890, RM7895 100 Vac

For More Information

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Combustion Safety, Eclipse, Exothermics, Hauck, Kromschröder and
Maxon. To learn more about our products, visit ThermalSolutions.
honeywell.com or contact your Honeywell Sales Engineer.

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32-00216-01 Edition 08.19
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