Electronic Controls

Handbook
Programming Flow Charts & Parameter Lists for

EWPC Series Controllers

A
Specialists in electronic refrigeration control
www.thermofrostcryo.co.uk

London
Tel. 020 8655 7600
Fax. 020 8761 8081

Birmingham
Tel. 0121 666 4700
Fax. 0121 622 7268

Caution
This handbook has been produced by Thermofrost Cryo PLC
Its unauthorised reproduction and or distribution in part or in whole, is an infringement of copyright
 Eliwell Controls
Programming Flow Charts & Parameters
General -
Installation & setup suggestions page 3
Adverse Condition Protection page 32

Programming & Flowcharts -

EWPC901T/AR Single step thermostat. page 4
EWPC902T/R/P Single step thermostat. page 6
EWPC905T Two step/neutral zone thermostat page 8
EWTR910T Single step thermostat. page 10
EWTR920T Two step thermostat. page 10
EWTR930T Neutral zone thermostat. page 12
EWPC961T/AR Single step thermostat with off page 14
cycle defrost / and alarm.
EWPC970T Single step thermostat / defrost with page 16
temperature termination.
EWPC971T Single step thermostat / defrost with page 18
fan delay.
EWPC972T Single step thermostat / defrost with page 20
fan delay and temp. termination.
EWPC974T/AL Single step thermostat / defrost with page 23
fan delay, temp. termination and alarm.
EWPC977T/AL Single step thermostat / defrost with page 25
temp. termination and alarm.
EWPC1000 Coldroom control unit ( panel mounted ) page 28
EWTB1000 Coldroom control unit ( wall mounted ) page 28
EWDR975 Defrost control for dual circuits page 31

2
The Programming Flow Charts & Parameter explanations shown in this brochure are
designed to assist in the installation and service of Eliwell micro-processor based
controls. Unfortunately it would be impractical to cover all of the Eliwell range in such a
brochure so we have concentrated on the more commonly used models.

This booklet is not designed to replace the original manufacturers instruction booklet (
which is supplied with each new control ) but to provide additional guidance.
Eliwell Control Installation & Set-up Suggestions

Fault signals - 'E1' = room sensor fault - check wiring & connections between control and sensor. If no fault in wiring, check sensor
resistance value as per table shown below. 'E2' = evaporator sensor fault - check as per E1.
Sensors - Eliwell controls predominantly use PTC sensors with NI100 & PT100 types also being used on some models.
Sensors - connections - preferably use screw connection blocks or spade connections.
Sensors - extension - PTC sensors are extendable to a max. of 100 mtrs using 1,5 mm square section conductor cable.
Sensors - interference - avoid running sensor leads close to other electrical equipment and other cables conducting large switching
loads. If this is unavoidable, use screened cable, earthed at both ends.
Sensors - resistances - sensor temperature (degree C.) / ohms resistance

-10 C 0C +10 C +20 C

PTC 740 800 877 950
NI100 94,6 100 105,6 111
PT100 96,1 100 104 108

Sensors - operating temps - sensor operating range cable ambient range

PTC - 55 to + 140 C PVC - 20 to + 80 C

PTC(W) * - 55 to + 140 C Silicone - 90 to + 200 C
NI100 - 50 to + 150 C Vetrotex(P) 0 to + 550 C
PT100 - 90 to + 600 C Vetrotex(P) 0 to + 550 C
* waterproof / high ambient sensor ( optional ).

Spikes - if power spikes are possible, fit a Varisitor in parallel with the power and neutral lines to the transformer on the 240v input
side. Ask for part no. CON210. Refer to inside back cover - Adverse Condition Protection.
Supply fluctuation - if the supply voltage drops below an acceptable level, the control display will flash indicating that the problem
exists. During this time all functions are suspended until the correct voltage returns and the control resumes its normal programmed
operation.
Power - most Eliwell controls are for connection to either mains 240v.1.50Hz supply or 12 VAC/DC ( normally fed from either a
remote slave unit or a 3VA transformer ).
Power interruption - Eliwell controls will retain the entered operating program during a power failure. However, it is good practice
to use the 'cleanest' available power supply. If the supply is also used for controlling large electrical loads, fit a 'noise filter' ( part no.
CON200 ). Refer to inside back cover - Adverse Condition Protection.
Programming - most Eliwell controls will retain the program memory for several years without an external power supply. This
allows the control to be programmed 'on the bench' before issuing for site installation.
Outputs - check that the switching currents applied are within the ratings shown on the control & in the control detail.
Output interference - if the control is connected to an inductive coil (e.g. solenoid valves, etc. ) it is possible to pick up and transmit
interference back to the control thus causing errors. If this could be a problem, fit a noise filter (part no. PELE342) in parallel,
preferably across the coil. Refer to inside back cover - Adverse Condition Protection.
Water / humidity - the EWPC900 & EWTB/EWPC1000 series controls have an IP65 rated front fascia. To provide a complete IP65
rated seal for the front fascia of a 74 x 32 mm control, a rubber gasket ( part no. PELE206 ) should be fitted between the back face of
the control fascia and the panel mounting face. The control does require ventilation and therefore has ventilation slats on both sides of
the control housing. These slats are designed to resist the intake of moisture but for 'drip' protection for the terminal connections, a
protection kit ( part no. PELE205 ) is available.

Setting the Set Point - after programming the control, ensure that the SET POINT value has also been entered.

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

3
 Read
Note
EWPC901 / T with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright
Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“HC” --- Thermostat probe fault
EEE Thermostat probe fault
E3 Program error – loss of settings
E6 Data corruption – electrical noise
You are now in programming mode.
See note
Not all codes will be present in every controller

Release “SET” button

Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

4
 Eliwell EWPC901T / AR Parameters
PARAMETERS FUNCTIONS / OPTIONS
SP Sets the temperature at which the relay opens
Set Point
HC H = Heating applications, differential is below Set Point (relay makes on fall)
Heating / Cooling C = Cooling applications, differential is above Set Point (relay makes on rise)
d Sets the number of degrees above (or below) Set Point at which the relay closes
Differential
LS Sets the lowest value to which customer will be able to adjust set point.
Lower Set Point
limit
HS Sets the highest value to which customer will be able to adjust set point.
Higher Set Point
limit
CA Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
Calibration
thermostat probe
rP If sensor / wiring is defective, the compressor relay will –
Compressor probe oF = Open ( ie. compressor is switched off until fault is corrected ).
protection on = Close ( ie. compressor runs continuously until fault is corrected ).
PS 0 = delay, in seconds, before compressor starts (enter value in Pt below)
Protection type 1 = delay, in minutes, before compressor starts (enter value in Pt below)
2 = after compressor stops, a delay, in minutes, before it can re-start (enter value
in Pt below ).
3 = delay, in minutes, between successive compressor starts ( enter value in Pt
below ).
Pt Time period for parameter PS as above ( enter value between 0 > 31, mins or secs ).
Protection time
HA Temperature deviation above set point at which internal alarm will be activated
High Temp Alarm ( value entered must be positive ' + ' ).

LA Temperature deviation below set point at which internal alarm will be activated
Low Temp Alarm ( value entered must be positive ' + ' ).

Ad Temperature differential for HA & LA alarms.

Alarm differential
PA Alarm time delay, in hours, after start-up during which alarm will not activate.
Power on alarm
delay

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

5
 Read
Note EWPC902 / T with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“HC” --- Thermostat probe fault
EEE Thermostat probe fault
E3 Program error – loss of settings
E6 Data corruption – electrical noise
You are now in programming mode.
See note
Not all codes will be present in every controller

Release “SET” button

Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

6
 Eliwell EWPC902T/R/P Parameters
PARAMETERS FUNCTIONS / OPTIONS
SP Sets the temperature at which the relay opens
Set Point
d1 Sets the number of degrees above (or below) Set Point at which the relay closes
Differential
LS 1 Sets the lowest value to which customer will be able to adjust set point.
Lower Set Point
limit
HS 1 Sets the highest value to which customer will be able to adjust set point.
Higher Set Point
limit
od Delay in minutes between power coming on and output relays activating
Output delay
Lci For pressure and humidity models only. Set to same value as that of the transducer
Lower current input or humidity probe’s bottom end of scale. (see note below)
Hci For pressure and humidity models only. Set to same value as that of the transducer
Higher current input or humidity probe’s upper end of scale. (see note below)
CAL Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
Calibration
thermostat probe
PSE Ni = Ni100 (RTD)
Probe type selection Pt = PT100 (RTD)
FE = J type thermocouple
Cr = K type thermocouple
rh = S type thermocouple
HC 1 H = Heating / De-hum etc., differential is below Set Point (relay makes on fall)
Heating / Cooling C = Cooling / Hum etc., differential is above Set Point (relay makes on rise)
rp1 If sensor / wiring is defective, the relay will –
Relay protection ro = Open ( ie. compressor is switched off until fault is corrected ).
rc = Close ( ie. compressor runs continuously until fault is corrected ).
LF1 di = LED on when relay is energised
LED function 1 in = LED off when relay is energised
dP oF = No decimal point in readout
Decimal Point on = Will show decimal point in readout ( if this function selected see notes below)
Note 1 - current & voltage input models, if this option selected, parameters 'Lci' & 'H
must be entered as 10 times actual value.
Note 2 - all models - if changed from non-decimal to decimal readout, all parameters
entered in degrees will be automatically divided by 10.
Note 3 - this function not applicable to models with thermocouple input.
Hdd Half digit On / Off - Used to make the display’s right hand digit read full scale
Half digit display ( 0 to 9 ) or half digit only ( 0 or 5 )
tAb Do not alter this setting
Do not adjust

Note - Pressure & Humidity models : You must adjust the controller to the working range of the sensor.
For example, if you have a humidity probe with a working range of 20÷80%RH, you must enter the value
“20” into parameter Lci, and “80” into parameter Hci

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

7
 Read
Note EWPC905 / T with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“db” or “d1” --- Thermostat probe fault
EEE Thermostat probe fault
E3 Program error – loss of settings
E6 Data corruption – electrical noise
You are now in programming mode.
See note
Not all codes will be present in every controller

Release “SET” button

Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters Now enter the required

been set ? Set Points by pressing &
releasing the “SET”
button once for Set
Point 1 & twice for Set Finally, switch power off
Yes then on again after a few
Point 2, (if 2 stage), then
adjust with the seconds to update all new
& buttons settings
Allow control approx. 10 seconds to
If set as 2 stage control,
exit programming mode Programming is
Set Point 2 as
See Note complete
differential value below
Set Point 1
(see Param. table)

8
 Eliwell EWPC905T Parameters
Important Note: Parameter “Ft” sets EWPC905 to act as either a 2 stage or Dead Band Controller.
Set parameter “Ft” before setting any other parameter

PARAMETERS FUNCTIONS / OPTIONS

d 1 Differential for Sets the number of degrees above (or below) Set Point 1 at which relay 1 closes
Set Point 1 (Also see parameters HC1 & Ft)
d2 Differential for Sets the number of degrees above (or below) Set Point 1 at which relay 2 closes
Set Point 2 (Also see parameters HC2 & Ft)
db Sets the number of degrees above and below Set Point, at which the respective
Dead band relays close. Relays will open again when Set Point is achieved.
LS 1 Lower limit Sets the lowest value to which customer will be able to adjust Set Point 1.
for Set Point 1
LS 2 Lower limit Sets the lowest value to which customer will be able to adjust Set Point 2.
for Set Point 2
HS 1 Higher limit Sets the highest value to which customer will be able to adjust set point 1.
for Set Point 1
HS 2 Higher limit Sets the highest value to which customer will be able to adjust set point 2.
for Set Point 2
od Output delay Delay in seconds between power coming on and output relays activating

Lci For pressure and humidity models only. Set to same value as that of the transducer
Lower current input or humidity probe’s bottom end of scale. (see note below)
Hci For pressure and humidity models only. Set to same value as that of the transducer
Higher current input or humidity probe’s upper end of scale. (see note below)
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
thermostat probe
Ft Sets the EWPC905 to operate as a 2 stage or dead band controller
Function type on = 2 stage control nr = Dead band control
OCO di = Set Point 2 is dependent on Set Point 1. Alter 1 and 2 will follow it
Set Points 1 & 2 (Here, the temperature entered in Set Point 2 is the deviation from Set Point 1)
dependent or in = Both Set Points independent of each other
independent Note: di (dependent) is only possible if parameter “Ft” = on (2 stage operation)
HC 1 Relay 1 H = Heating / De-hum etc., differential is below Set Point (relay makes on fall)
Heating / Cooling C = Cooling / Hum etc., differential is above Set Point (relay makes on rise)
HC 2 Relay 2 H = Heating / De-hum etc., differential is below Set Point (relay makes on fall)
Heating / Cooling C = Cooling / Hum etc., differential is above Set Point (relay makes on rise)
rP1 If sensor / wiring is defective, the relay 1 will –
Relay 1 protection ro = Open ( ie. compressor is switched off until fault is corrected ).
rc = Close ( ie. compressor runs continuously until fault is corrected ).
rP2 If sensor / wiring is defective, the relay 2 will –
Relay 2 protection ro = Open ( ie. compressor is switched off until fault is corrected ).
rc = Close ( ie. compressor runs continuously until fault is corrected ).
LF1 di = LED on when relay 1 is energised
LED function 1 in = LED off when relay 1 is energised
LF2 di = LED on when relay 2 is energised
LED function 2 in = LED off when relay 2 is energised
dP oF = No decimal point in readout
Decimal Point on = Will show decimal point in readout
Hdd Half digit On / Off - Used to make the display’s right hand digit read full scale
Half digit display ( 0 to 9 ) or half digit only ( 0 or 5 )
tAb Do not adjust Do not alter this setting
Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

9
 Read EWTR910 / 920
Note with Ni100 or PT100 (RTD) sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “PRG, EWTR Display Reason
& SET (1) buttons together until the Flashing
display changes to read E1 Thermostat probe fault
“d1” --- Thermostat probe fault
EEE Thermostat probe fault
E3 Program error – loss of settings
E6 Data corruption – electrical noise
You are now in programming mode.
See note
Not all codes will be present in every controller

Release all buttons

Display now shows first parameter
See list opposite

Press & release “SET (1)” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET (1)” button

Quickly press & release button. Press & release “SET (1)” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET (1)” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode NB “dro” must be at Programming is
See Note “P” complete

10
 Eliwell EWTR910 / 920 Parameters
Important Notes: Parameter “dP” decimal point on / off can effect some other parameters by a factor of
10. Always set “dP” first . Not all parameters listed may be present in every controller
PARAMETERS FUNCTIONS / OPTIONS
d 1 Differential for Sets the number of degrees above (or below) Set Point 1 at which relay 1 closes
Set Point 1 (Also see parameters HC1 & Ft)
d2 Differential for Sets the number of degrees above (or below) Set Point 1 at which relay 2 closes
Set Point 2 (Also see parameters HC2 & Ft)
db Sets the number of degrees above and below Set Point, at which the respective relays close.
Dead band Relays will open again when Set Point is achieved.
LS 1 Lower limit for Sets the lowest value to which customer will be able to adjust Set Point 1.
Set Point 1
LS 2 Lower limit for Sets the lowest value to which customer will be able to adjust Set Point 2.
Set Point 2
HS 1 Higher limit for Sets the highest value to which customer will be able to adjust set point 1.
Set Point 1
HS 2 Higher limit for Sets the highest value to which customer will be able to adjust set point 2.
Set Point 2
od Output delay Delay in seconds between “power on” and output relays starting to operate
Lci For pressure and humidity models only. Set to same value as that of the transducer
Lower current input or humidity probe’s bottom end of scale. (see note below)
Hci For pressure and humidity models only. Set to same value as that of the transducer
Higher current input or humidity probe’s upper end of scale. (see note below)
LAO Low analogue Sets the temperature at which the analogue output will be at 4mA
output (for models with 4-20mA analogue output only) Also see parameter “AOF”
HAO High analogue Sets the temperature at which the analogue output will be at 20mA
output (for models with 4-20mA analogue output only) Also see parameter “AOF”
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
PSE Probe selection NI = Ni100 Pt = PT100
AOF Analogue output ro = Temperatures entered into LAO & HAO are actual temperatures and remain
function fixed even if the Set Point is altered.
Er = The analogue output is linked to the Set Point. If Set Point is altered, the
the analogue output will follow, and the relationship between LAO, HAO &
Set Point will be maintained. Temperatures entered into LAO & HAO
are not actual temperatures, but are the deviation away from Set Point
Note: The 4-20mA analogue output is always proportional between LAO & HAO
OCO di = Set Point 2 is dependent on Set Point 1. Alter 1 and 2 will follow it
Set Points dependent (Here, the temperature entered in Set Point 2 is the deviation from Set Point 1)
or independent in = Both Set Points independent of each other
HC 1 Relay 1 H = Heating / De-hum etc., differential is below Set Point (relay makes on fall)
Heating / Cooling C = Cooling / Hum etc., differential is above Set Point (relay makes on rise)
HC 2 Relay 2 H = Heating / De-hum etc., differential is below Set Point (relay makes on fall)
Heating / Cooling C = Cooling / Hum etc., differential is above Set Point (relay makes on rise)
rP1 If sensor / wiring is defective, the relay 1 will –
Relay 1 protection ro = Open ( ie. compressor is switched off until fault is corrected ).
rc = Close ( ie. compressor runs continuously until fault is corrected ).
rP2 If sensor / wiring is defective, the relay 2 will –
Relay 2 protection ro = Open ( ie. compressor is switched off until fault is corrected ).
rc = Close ( ie. compressor runs continuously until fault is corrected ).
LF1 LED function 1 di = LED on when relay 1 is energised in = LED off when relay 1 is energised
LF2 LED function 2 di = LED on when relay 2 is energised in = LED off when relay 2 is energised
dP Decimal Point oF = No decimal point in readout on = Will show decimal point in readout
dro Display readout P = Display system temperature S = Display Set Point
AOS Analogue Output Ao = Analogue output goes to 20mA if sensor fails
Security AF = Analogue output goes to 4 mA if sensor fails
Hdd Half digit On / Off - Used to make the display’s right hand digit read full scale
Half digit display ( 0 to 9 ) or half digit only ( 0 or 5 )
tAb Do not adjust Do not alter this setting

11
 Read EWTR930
Note with Ni100 or PT100 (RTD) sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “PRG, EWTR Display Reason
& SET (1) buttons together until the Flashing
display changes to read E1 Thermostat probe fault
“db” --- Thermostat probe fault
EEE Thermostat probe fault
E3 Program error – loss of settings
E6 Data corruption – electrical noise
You are now in programming mode.
See note
Not all codes will be present in every controller

Release all buttons

Display now shows first parameter
See list opposite

Press & release “SET ” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET ” button

Quickly press & release button. Press & release “SET ” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode NB “dro” must be at Programming is
See Note “P” complete

12
 Eliwell EWTR930 Parameters
Important Notes: Parameter “dP” decimal point on / off can effect some other parameters by a factor of
10. Always set “dP” first . Not all parameters listed may be present in every controller
PARAMETERS FUNCTIONS / OPTIONS
db Sets the number of degrees above and below Set Point, at which the respective relays close.
Dead band Relays will open again when Set Point is achieved.
LS 1 Lower limit for Sets the lowest value to which customer will be able to adjust Set Point 1.
Set Point 1
HS 1 Higher limit for Sets the highest value to which customer will be able to adjust set point 1.
Set Point 1
od Output delay Delay in seconds between “power on” and output relays starting to operate
Lci For pressure and humidity models only. Set to same value as that of the transducer
Lower current input or humidity probe’s bottom end of scale. (see note below)
Hci For pressure and humidity models only. Set to same value as that of the transducer
Higher current input or humidity probe’s upper end of scale. (see note below)
LAO Low analogue Sets the temperature at which the analogue output will be at 4mA
output (for models with 4-20mA analogue output only) Also see parameter “AOF”
HAO High analogue Sets the temperature at which the analogue output will be at 20mA
output (for models with 4-20mA analogue output only) Also see parameter “AOF”
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
PSE Probe selection NI = Ni100 Pt = PT100
AOF Analogue output ro = Temperatures entered into LAO & HAO are actual temperatures and remain
function fixed even if the Set Point is altered.
Er = The analogue output is linked to the Set Point. If Set Point is altered, the
the analogue output will follow, and the relationship between LAO, HAO &
Set Point will be maintained. Temperatures entered into LAO & HAO
are not actual temperatures, but are the deviation away from Set Point
Note: The 4-20mA analogue output is always proportional between LAO & HAO
rP1 If sensor / wiring is defective, the relay 1 will –
Relay 1 protection ro = Open ( ie. compressor is switched off until fault is corrected ).
rc = Close ( ie. compressor runs continuously until fault is corrected ).
rP2 If sensor / wiring is defective, the relay 2 will –
Relay 2 protection ro = Open ( ie. compressor is switched off until fault is corrected ).
rc = Close ( ie. compressor runs continuously until fault is corrected ).
LF1 LED function 1 di = LED on when relay 1 is energised in = LED off when relay 1 is energised
LF2 LED function 2 di = LED on when relay 2 is energised in = LED off when relay 2 is energised
dP Decimal Point oF = No decimal point in readout on = Will show decimal point in readout
dro Display readout P = Display system temperature S = Display Set Point
AOS Analogue Output Ao = Analogue output goes to 20mA if sensor fails
Security AF = Analogue output goes to 4 mA if sensor fails
Hdd Half digit On / Off - Used to make the display’s right hand digit read full scale
Half digit display ( 0 to 9 ) or half digit only ( 0 or 5 )
tAb Do not adjust Do not alter this setting

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

13
 Read
Note EWPC961T / AR with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“d” --- Thermostat probe fault
EEE Thermostat probe fault
E3 Program error – loss of settings
E6 Data corruption – electrical noise
You are now in programming mode.
See note
Not all codes will be present in every controller

Release “SET” button

Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

14
 Eliwell EWPC961T / AR Parameters
PARAMETERS FUNCTIONS / OPTIONS
d Differential Sets the number of degrees above Set Point at which the compressor is re-started
LS Lower Set Sets the lowest value to which customer will be able to adjust set point.
Point limit
HS Higher Set Sets the highest value to which customer will be able to adjust set point.
Point limit
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 15 deg..
thermostat probe
rP Compressor If sensor / wiring is defective, the compressor relay will –
probe protection oF = Open ( ie. compressor is switched off until fault is corrected ).
on = Close ( ie. compressor runs continuously until fault is corrected ).
PS Compressor 0 = delay, in seconds, before compressor starts (enter value in Pt below)
protection system 1 = delay, in minutes, before compressor starts (enter value in Pt below)
2 = after compressor stops, a delay, in minutes, before it can re-start (enter value
in Pt below ).
3 = delay, in minutes, between successive compressor starts (enter value in Pt below)
Pt Protection time Time period for parameter PS as above ( enter value between 0 > 31, mins or secs ).
dS Defrost System dF = defrost period based upon compressor running time in hours (Digifrost ).
rt = defrost period based upon real ( clock ) time.
dI Defrost Interval Time period, in hours, between defrost starts ( see dS above ).
dE Defrost Maximum length of defrost, in minutes.
Endurance
dL Defrost display n = Display will continue to show sensor temperature during defrost.
Lock y = During defrost, display will be 'locked' - for options see dr below.
dr Display readout If dL ( as above ) is set to 'y', this determines locked display shown during defrost -
unit C = Display locked on the temperature showing prior to defrost.
df = Display locked to show '' df " indicating defrost in progress
Note : Either display will remain 'locked' until the set point temp. is regained.
do Defrost at System will go into defrost when power supply is connected -
power on n = No.
y = Yes.
dd Defrost delay Delay, in minutes, after power on before defrost can start.
HA High temp. Temperature deviation above set point at which alarm will be activated ( value
Alarm entered must be positive ' + ' ) i.e. if set point is minus 10 deg C & required alarm tem
is minus 3 deg C, enter value " 7 ".
LA Low temp. Temperature deviation below set point at which alarm will be activated ( value
Alarm entered must be positive ' + ' ).
Ad Alarm Temperature differential for HAL & LAL alarm settings ( as above ).
differential
PA Power on alarm Alarm time delay after power on ( hours ).
delay
dA Defrost Alarm Alarm time delay after defrost ( see Au below ).
delay
Au Alarm time unit Selects unit ( hours or minutes ) for defrost alarm delay - see dA above.

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

15
 Read
Note EWPC970 T with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“dif” --- Thermostat probe fault
EEE Thermostat probe fault
E3 Program error – loss of settings
E6 Data corruption – electrical noise
You are now in programming mode.
See note
Not all codes will be present in every controller

Release “SET” button

Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

16
 Eliwell EWPC970T Parameters
PARAMETERS FUNCTIONS / OPTIONS
diF Differential Sets the number of degrees above Set Point at which the compressor is re-started
LSE Lower Set Sets the lowest value to which customer will be able to adjust set point.
Point limit
HSE Higher Set Sets the highest value to which customer will be able to adjust set point.
Point limit
dty Defrost type EL = Electric defrost.
in = Reverse cycle or hot-gas defrost.
dit Defrost interval Time period, in hours, between defrosts ( see dct below ).
dct Defrost counting dF = Defrost interval based upon compressor running time.
type rt = Defrost interval based upon real ( clock ) time.
SC = Goes into defrost when compressor stops.
Fr = Allows free use of defrost relay for other purposes i.e. isolation of separate
alarm system during defrost, etc..
doh Defrost offset If defrost on start up is required (see dPo below) then this parameter creates an
initial time period, in minutes, of normal operation before the defrost commences.
ie. if dPo is on 'Y' & doh is at '10', then on start-up system will run for 10 mins &
then go into defrost.
dEt Defrost duration Time period, in minutes, of defrost cycle
dt Drip time Time period, in minutes, at the end of defrost when compressor remains off
dPo Defrost at Instructs controller to carry out defrost when power supply is reconnected -
power on n = No.
y = Yes.
ddL Defrost display n = When system goes into defrost, display will show sensor temperature.
lock y = During defrost, display will lock on temperature shown at start of defrost.
Lb = Display shows 'def' throughout defrost cycle.
Note : Options 'y' & 'Lb' – display remains locked until set point temp is regained.
cPP Compressor If sensor / wiring is defective, the compressor relay will –
probe protection oF = Open ( ie. compressor is switched off until fault is corrected ).
on = Close ( ie. compressor runs continuously until fault is corrected ).
ctP Compressor type nP = No compressor short-cycling protection.
of protection don = A delay is created between signal for the compressor to run and the
compressor relay making ( for time period, see CdP below ).
doF = A delay is created between the compressor switching off and subsequent
re-start ( for time period, see CdP below ).
dbi = After compressor starts, there is a time period before it can restart ( for time
period, see cdP below )
cdP Compressor The time period, in minutes, for ctP (see above).
delay protection
odo Output delay at When power supply is switched on, all functions are delayed for this period ( in
power on mins. ).
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
thermostat probe
tab do not adjust Do not alter this setting

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

17
 Read
Note EWPC971 T with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“dif” --- Thermostat probe fault
EEE Thermostat probe fault
E2 Evaporator probe fault
E3 Program error – loss of settings
You are now in programming mode.
E6 Data corruption – electrical noise
See note
Not all codes will be present in every controller
Release “SET” button
Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

18
 Eliwell EWPC971T Parameters
Important: If using in conjunction with EWDR975, refer to pages 31 for special instructions
PARAMETERS FUNCTIONS / OPTIONS
diF Differential Sets the number of degrees above Set Point at which the compressor is re-started
LSE Lower Set Sets the lowest value to which customer will be able to adjust set point.
Point limit
HSE Higher Set Sets the highest value to which customer will be able to adjust set point.
Point limit
dty Defrost type EL = Electric defrost.
in = Reverse cycle or hot-gas defrost.
dit Defrost interval Time period, in hours, between defrosts ( see dct below ).
dct Defrost counting dF = Defrost interval based upon compressor running time.
type rt = Defrost interval based upon real ( clock ) time.
SC = Goes into defrost when compressor stops.
Fr = Allows free use of defrost relay for other purposes i.e. isolation of separate
alarm system during defrost, etc..
doh Defrost offset If defrost on start up is required (see dPo below) then this parameter creates an
initial time period, in minutes, of normal operation before the defrost commences.
ie. if dPo is on 'Y' & doh is at '10', then on start-up system will run for 10 mins &
then go into defrost.
dEt Defrost duration Time period, in minutes, of defrost cycle - maximum defrost time assuming dSt
value ( as below ) is not reached first.
dSt Defrost Temperature as sensed by evaporator probe, at which defrost cycle is terminated.
termination temp.
dt Drip time Time period, in minutes, at the end of defrost when compressor remains off
dPo Defrost at Instructs controller to carry out defrost when power supply is reconnected -
power on n = No.
y = Yes.
ddL Defrost display n = When system goes into defrost, display will show sensor temperature.
lock y = During defrost, display will lock on temperature shown at start of defrost.
Lb = Display shows 'def' throughout defrost cycle.
Note : Options 'y' & 'Lb' – display remains locked until set point temp is regained.
cPP Compressor If sensor / wiring is defective, the compressor relay will –
probe protection oF = Open ( ie. compressor is switched off until fault is corrected ).
on = Close ( ie. compressor runs continuously until fault is corrected ).
ctP Compressor type nP = No compressor short-cycling protection.
of protection don = A delay is created between signal for the compressor to run and the
compressor relay making ( for time period, see CdP below ).
doF = A delay is created between the compressor switching off and subsequent
re-start ( for time period, see CdP below ).
dbi = After compressor starts, there is a time period before it can restart ( for time
period, see cdP below )
cdP Compressor The time period, in minutes, for ctP (see above).
delay protection
odo Output delay at When power supply is switched on, all functions are delayed for this period ( in
power on mins. ).
EPr Evaporator Displays temperature sensed by the evaporator probe.
probe readout
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
thermostat probe
tab do not adjust Do not alter this setting

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

19
 Read
Note EWPC972 / 974 T with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“dif” --- Thermostat probe fault
EEE Thermostat probe fault
E2 Evaporator probe fault
E3 Program error – loss of settings
You are now in programming mode.
E6 Data corruption – electrical noise
See note
Not all codes will be present in every controller
Release “SET” button
Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

20
 Eliwell EWPC972T Parameters
Important: If using in conjunction with EWDR975, refer to pages 31 for special instructions
PARAMETERS FUNCTIONS / OPTIONS
diF Differential Sets the number of degrees above Set Point at which the compressor is re-started
LSE Lower Set Sets the lowest value to which customer will be able to adjust set point.
Point limit
HSE Higher Set Sets the highest value to which customer will be able to adjust set point.
Point limit
dty Defrost type EL = Electric defrost.
in = Reverse cycle or hot-gas defrost.
dit Defrost interval Time period, in hours, between defrosts ( see dct below ).
dct Defrost counting dF = Defrost interval based upon compressor running time.
type rt = Defrost interval based upon real ( clock ) time.
SC = Goes into defrost when compressor stops.
Fr = Allows free use of defrost relay for other purposes i.e. isolation of separate
alarm system during defrost, etc..
doh Defrost offset If defrost on start up is required (see dPo below) then this parameter creates an
initial time period, in minutes, of normal operation before the defrost commences.
ie. if dPo is on 'Y' & doh is at '10', then on start-up system will run for 10 mins &
then go into defrost.
dEt Defrost duration Time period, in minutes, of defrost cycle - maximum defrost time assuming dSt
value ( as below ) is not reached first.
dSt Defrost Temperature as sensed by evaporator probe, at which defrost cycle is terminated.
termination temp.
FSt Fan stop temp When temperature sensed by evaporator probe is above this setting, evap fans stop
Fdt Fan delay time Time period, in minutes, after end of defrost during which fans will remain stopped.
dt Drip time Time period, in minutes, at the end of defrost when both compressor & evap fans
remain off.. e.g. if Fdt = 5 mins & dt = 3 mins, then at end of defrost both compresso
& fans will remain off for 3 mins with evap. fans remaining off for a further 2 mins
(i.e. a total of 5 mins).
dPo Defrost at Instructs controller to carry out defrost when power supply is reconnected -
power on n = No.
y = Yes.
ddL Defrost display n = When system goes into defrost, display will show sensor temperature.
lock y = During defrost, display will lock on temperature shown at start of defrost.
Lb = Display shows 'def' throughout defrost cycle.
Note : Options 'y' & 'Lb' – display remains locked until set point temp is regained.
dFd Defrost fan n = Evaporator fans remain on during defrost.
disable y = Evaporator fans switch off during defrost.
AFd Fan differential Temperature differential for Fst (as above) and for HAL / LAL (as above).
Fco Fan compressor When the thermostat is satisfied -
off oF = Compressor & evaporator fans switch off
on = Compressor switches off - fans remain on.
cPP Compressor If sensor / wiring is defective, the compressor relay will –
probe protection oF = Open ( ie. compressor is switched off until fault is corrected ).
on = Close ( ie. compressor runs continuously until fault is corrected ).

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

Continued:-

21
Eliwell EWPC972T Parameters - continued

ctP Compressor type nP = No compressor short-cycling protection.

of protection don = A delay is created between signal for the compressor to run and the
compressor relay making ( for time period, see CdP below ).
doF = A delay is created between the compressor switching off and subsequent
re-start ( for time period, see CdP below ).
dbi = After compressor starts, there is a time period before it can restart ( for time
period, see cdP below )
cdP Compressor The time period, in minutes, for ctP (see above).
delay protection
odo Output delay at When power supply is switched on, all functions are delayed for this period ( in
power on mins. ).
EPr Evaporator Displays temperature sensed by the evaporator probe.
probe readout
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
thermostat probe
tab do not adjust Do not alter this setting

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

22
 Eliwell EWPC974T Parameters
Important: If using in conjunction with EWDR975, refer to pages 31 for special instructions
PARAMETERS FUNCTIONS / OPTIONS
diF Differential Sets the number of degrees above Set Point at which the compressor is re-started
LSE Lower Set Sets the lowest value to which customer will be able to adjust set point.
Point limit
HSE Higher Set Sets the highest value to which customer will be able to adjust set point.
Point limit
dty Defrost type EL = Electric defrost.
in = Reverse cycle or hot-gas defrost.
dit Defrost interval Time period, in hours, between defrosts ( see dct below ).
dct Defrost counting dF = Defrost interval based upon compressor running time.
type rt = Defrost interval based upon real ( clock ) time.
SC = Goes into defrost when compressor stops.
Fr = Allows free use of defrost relay for other purposes i.e. isolation of separate
alarm system during defrost, etc..
doh Defrost offset If defrost on start up is required (see dPo below) then this parameter creates an
initial time period, in minutes, of normal operation before the defrost commences.
ie. if dPo is on 'Y' & doh is at '10', then on start-up system will run for 10 mins &
then go into defrost.
dEt Defrost duration Time period, in minutes, of defrost cycle - maximum defrost time assuming dSt
value ( as below ) is not reached first.
dSt Defrost Temperature as sensed by evaporator probe, at which defrost cycle is terminated.
termination temp.
FSt Fan stop temp When temperature sensed by evaporator probe is above this setting, evap fans stop
Fdt Fan delay time Time period, in minutes, after end of defrost during which fans will remain stopped.
dt Drip time Time period, in minutes, at the end of defrost when both compressor & evap fans
remain off.. e.g. if Fdt = 5 mins & dt = 3 mins, then at end of defrost both compresso
& fans will remain off for 3 mins with evap. fans remaining off for a further 2 mins
(i.e. a total of 5 mins).
dPo Defrost at Instructs controller to carry out defrost when power supply is reconnected -
power on n = No.
y = Yes.
ddL Defrost display n = When system goes into defrost, display will show sensor temperature.
lock y = During defrost, display will lock on temperature shown at start of defrost.
Lb = Display shows 'def' throughout defrost cycle.
Note : Options 'y' & 'Lb' – display remains locked until set point temp is regained.
dFd Defrost fan n = Evaporator fans remain on during defrost.
disable y = Evaporator fans switch off during defrost.
HAL High temp Temperature offset above the set point at which LED & alarm output signal will be
alarm activated ( value entered must be positive ' + ' ).
LAL Low temp Temperature offset below the set point at which LED & alarm output signal will be
alarm activated ( value entered must be positive ' + ' ).
AFd Alarm / Fan Temperature differential for Fst (as above) and for HAL / LAL (as above).
differential

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

Continued:-

23
Eliwell EWPC974T Parameters - continued

PAo Power on alarm Delay, in hours, before alarm activates after power supply is connected
o/ride
dAo Defrost alarm Alarm delay, in hours, initiated after defrost cycle has been completed.
o/ride
Fco Fan compressor When the thermostat is satisfied -
off oF = Compressor & evaporator fans switch off
on = Compressor switches off - fans remain on.
cPP Compressor If sensor / wiring is defective, the compressor relay will –
probe protection oF = Open ( ie. compressor is switched off until fault is corrected ).
on = Close ( ie. compressor runs continuously until fault is corrected ).
ctP Compressor type nP = No compressor short-cycling protection.
of protection don = A delay is created between signal for the compressor to run and the
compressor relay making ( for time period, see CdP below ).
doF = A delay is created between the compressor switching off and subsequent
re-start ( for time period, see CdP below ).
dbi = After compressor starts, there is a time period before it can restart ( for time
period, see cdP below )
cdP Compressor The time period, in minutes, for ctP (see above).
delay protection
odo Output delay at When power supply is switched on, all functions are delayed for this period ( in
power on mins. ).
EPr Evaporator Displays temperature sensed by the evaporator probe.
probe readout
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
thermostat probe
AoP Alarm output Allows selection of alarm relay function -
polarity In = Relay opens during alarm condition.
di = Relay closes during alarm condition.
OSU Zero y = Eliminates the prefix zero in 3-figure display.
suppression n = Allows prefix zero to appear in display. e.g..'020'
tab do not adjust Do not alter this setting

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

24
 Read
Note EWPC977 with PTC sensor
Information courtesy of Thermofrost Cryo PLC – Copyright

Power
On Note
Controller will automatically exit programming mode, if no button is
pressed for 10 seconds. Any alteration that has been made will be
Display will flash “8.8.8” for about 6
stored. To re-enter programming mode, start again at Instruction 1
seconds then show temperature
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” button for Display Reason
about 10 seconds until display Flashing
changes to read E1 Thermostat probe fault
“dif” --- Thermostat probe fault
EEE Thermostat probe fault
E2 Evaporator probe fault
E3 Program error – loss of settings
You are now in programming mode.
E6 Data corruption – electrical noise
See note
Not all codes will be present in every controller
Release “SET” button
Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

25
 Eliwell EWPC977 Parameters
PARAMETERS FUNCTIONS / OPTIONS
diF Differential Sets the number of degrees above Set Point at which the compressor is re-started
LSE Lower Set Sets the lowest value to which customer will be able to adjust set point.
Point limit
HSE Higher Set Sets the highest value to which customer will be able to adjust set point.
Point limit
dty Defrost type EL = Electric defrost.
in = Reverse cycle or hot-gas defrost.
dit Defrost interval Time period, in hours, between defrosts ( see dct below ).
dct Defrost counting dF = Defrost interval based upon compressor running time.
type rt = Defrost interval based upon real ( clock ) time.
SC = Goes into defrost when compressor stops.
Fr = Allows free use of defrost relay for other purposes i.e. isolation of separate
alarm system during defrost, etc..
doh Defrost offset If defrost on start up is required (see dPo below) then this parameter creates an
initial time period, in minutes, of normal operation before the defrost commences.
ie. if dPo is on 'Y' & doh is at '10', then on start-up system will run for 10 mins &
then go into defrost.
dEt Defrost duration Time period, in minutes, of defrost cycle - maximum defrost time assuming dSt
value ( as below ) is not reached first.
dSt Defrost Temperature as sensed by evaporator probe, at which defrost cycle is terminated.
termination temp.
dt Drip time Time period, in minutes, at the end of defrost when compressor remains off
dPo Defrost at Instructs controller to carry out defrost when power supply is reconnected -
power on n = No.
y = Yes.
ddL Defrost display n = When system goes into defrost, display will show sensor temperature.
lock y = During defrost, display will lock on temperature shown at start of defrost.
Lb = Display shows 'def' throughout defrost cycle.
Note : Options 'y' & 'Lb' – display remains locked until set point temp is regained.
HAL High temp Temperature offset above the set point at which LED & alarm output signal will be
alarm activated ( value entered must be positive ' + ' ).
LAL Low temp Temperature offset below the set point at which LED & alarm output signal will be
alarm activated ( value entered must be positive ' + ' ).
AFd Alarm / Fan Temperature differential for Fst (as above) and for HAL / LAL (as above).
differential
PAo Power on alarm Delay, in hours, before alarm activates after power supply is connected
o/ride
dAo Defrost alarm Alarm delay, in hours, initiated after defrost cycle has been completed.
o/ride
cPP Compressor If sensor / wiring is defective, the compressor relay will –
probe protection oF = Open ( ie. compressor is switched off until fault is corrected ).
on = Close ( ie. compressor runs continuously until fault is corrected ).

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

Continued:-

26
Eliwell EWPC977 Parameters - continued
ctP Compressor type nP = No compressor short-cycling protection.
of protection don = A delay is created between signal for the compressor to run and the
compressor relay making ( for time period, see CdP below ).
doF = A delay is created between the compressor switching off and subsequent
re-start ( for time period, see CdP below ).
dbi = After compressor starts, there is a time period before it can restart ( for time
period, see cdP below )
cdP Compressor The time period, in minutes, for ctP (see above).
delay protection
odo Output delay at When power supply is switched on, all functions are delayed for this period ( in
power on mins. ).
EPr Evaporator Displays temperature sensed by the evaporator probe.
probe readout
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
thermostat probe
AoP Alarm output Allows selection of alarm relay function -
polarity In = Relay opens during alarm condition.
di = Relay closes during alarm condition.
tab do not adjust Do not alter this setting

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

27
 Read
Note EWPC / EWTB 1000 /C / S
Information courtesy of Thermofrost Cryo PLC – Copyright
Power
On
Note
Controller will automatically exit programming mode, if no button is
Display will flash “8.8.8” for about 6 pressed for 10 seconds. Any alteration that has been made will be
seconds then show temperature stored. To re-enter programming mode, start again at Instruction 1
sensed by room probe

ELIWELL ALARM CODES

Instruction 1
Press & hold down “SET” & Reason
Display
“HIDDEN” button until display
Flashing
changes to read “dif”
E0 Pressure switch error
Note: Hidden button is at the top
E1 Thermostat probe fault
right corner of front panel
--- Thermostat probe fault
EEE Thermostat probe fault
E2 Evaporator probe fault
You are now in programming mode.
E3 Program error – loss of settings
See note
E6 Data corruption – electrical noise

Release “SET” button Not all codes will be present in every controller
Display now shows first parameter
See list opposite

Press & release “SET” button to

display parameter’s current setting No To adjust, use the & buttons
Is the setting correct ?

Yes

Press & release “SET” button

Quickly press & release button. Press & release “SET” button. The new setting has
The next parameter is displayed now been entered. The display shows the parameter
just entered

No Have all the required parameters

been set ?

Now enter the required Finally, switch power off

Yes Set Point by pressing & then on again after a few
releasing the “SET” seconds to update all new
button & adjusting with settings
Allow control approx. 10 seconds to the & buttons
exit programming mode Programming is
See Note complete

28
Eliwell EWPC & EWTB 1000 Parameters
PARAMETERS FUNCTIONS / OPTIONS
diF Differential Sets the number of degrees above Set Point at which the compressor is re-started
LSE Lower Set Sets the lowest value to which customer will be able to adjust set point.
Point limit
HSE Higher Set Sets the highest value to which customer will be able to adjust set point.
Point limit
dty Defrost type EL = Electric defrost.
in = Reverse cycle or hot-gas defrost.
dit Defrost interval Time period, in hours, between defrosts ( see dct below – enter ‘0’ value ).
dct Defrost counting dF = Defrost interval based upon compressor running time.
type rt = Defrost interval based upon real ( clock ) time (see dit above & dtl below )
SC = Goes into defrost when compressor stops.
dtl Real time dt1 = Defrost start time settings - upto 6 sequential set times per 24 hrs ( dt1 > dt6 )
defrost set oF = Real ( clock ) time settings switched off.
doh Defrost offset If defrost on start up is required (see dPo below) then this parameter creates an
initial time period, in minutes, of normal operation before the defrost commences.
ie. if dPo is on 'Y' & doh is at '10', then on start-up system will run for 10 mins &
then go into defrost.
dEt Defrost duration Time period, in minutes, of defrost cycle - maximum defrost time assuming dSt
value ( as below ) is not reached first.
dSt Defrost Temperature as sensed by evaporator probe, at which defrost cycle is terminated.
termination temp.
POS Postpone time If system condition prevents a programmed defrost, this allows either postponement
( until condition has been rectified ) or cancellation of the defrost -
n = Cancel defrost
y = Postpone defrost
FSt Fan stop temp When temperature sensed by evaporator probe is above this setting, evap fans stop
Fdt Fan delay time Time period, in minutes, after end of defrost during which fans will remain stopped.
dt Drip time Time period, in minutes, at the end of defrost when both compressor & evap fans
remain off.. e.g. if Fdt = 5 mins & dt = 3 mins, then at end of defrost both compresso
& fans will remain off for 3 mins with evap. fans remaining off for a further 2 mins
(i.e. a total of 5 mins).
dPo Defrost at Instructs controller to carry out defrost when power supply is reconnected -
power on n = No.
y = Yes.
ddL Defrost display n = When system goes into defrost, display will show sensor temperature.
lock y = During defrost, display will lock on temperature shown at start of defrost.
Lb = Display shows 'def' throughout defrost cycle.
Note : Options 'y' & 'Lb' – display remains locked until set point temp is regained.
dFd Defrost fan n = Evaporator fans remain on during defrost.
disable y = Evaporator fans switch off during defrost.
HAL High temp Temperature offset above the set point at which LED & alarm output signal will be
alarm activated ( value entered must be positive ' + ' ).
LAL Low temp Temperature offset below the set point at which LED & alarm output signal will be
alarm activated ( value entered must be positive ' + ' ).
AFd Alarm / Fan Temperature differential for Fst (as above) and for HAL / LAL (as above).
differential
PAo Power on alarm Delay, in hours, before alarm activates after power supply is connected
o/ride
Information courtesy of Thermofrost Cryo PLC – Copyright September 2000
Continued:-

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Eliwell EWPC & EWTB 1000 Parameters - continued
dAo Defrost alarm Alarm delay, in hours, initiated after defrost cycle has been completed.
o/ride
oAo Door Alarm Door alarm delay, in hours, after door opening.
over-ride
cAo Cont. cycle After a continuous cycle operation has been manually initiated, the temp. alarm can
Alarm o/r be delayed for this period ( hours ).
cct Continuous Duration of continuous cycle operation during which compressor will run regardless
cycle time of thermostat signal ( in hours ).
Fco Fan compressor When the thermostat is satisfied -
off oF = Compressor & evaporator fans switch off
on = Compressor switches off - fans remain on.
Fod Fan / door oF = Evaporator fans switch off when doors are open.
delay on = Fans remain on with door open.
cPP Compressor If sensor / wiring is defective, the compressor relay will –
probe protection oF = Open ( ie. compressor is switched off until fault is corrected ).
on = Close ( ie. compressor runs continuously until fault is corrected ).
ctP Compressor type nP = No compressor short-cycling protection.
of protection don = A delay is created between signal for the compressor to run and the
compressor relay making ( for time period, see CdP below ).
doF = A delay is created between the compressor switching off and subsequent
re-start ( for time period, see CdP below ).
dbi = After compressor starts, there is a time period before it can restart ( for time
period, see cdP below )
cdP Compressor The time period, in minutes, for ctP (see above).
delay protection
PEn Pressure Error Number of acceptable pressure switch trips within specific time period
number (see PEI below).
PEI Pressure Error Specific time period for PEn as above.
Interval
odo Output delay When power supply is switched on, all functions are delayed for this period
at power on ( in mins. ).
dod Door open Switch off compressor & evaporator fans when door open -
shut-down n = No.
y = Yes.
dSd Door open / Switch on lights when door is open -
light n = No.
y = Yes.
ldd Light / door Door operated switch continues to function if EWPC/EWTB control is switched off
disable ( but still powered up ) -
n = No
y = Yes
EPr Evaporator Displays temperature sensed by the evaporator probe.
probe readout
CAL Calibration Enables the sensor display temperature to be re-calibrated or offset by + / - 20 deg..
thermostat probe
dEA Device address Applicable to TELEVIS version only - refer to TELEVIS installation instructions.
dEF Device Family Applicable to TELEVIS version only - refer to TELEVIS installation instructions.
tab do not adjust Do not alter this setting
Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

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Eliwell EWDR975
This supplementary device is used in conjunction with Eliwell 'DIGIFROST' controllers such as EWPC971,
972 or 974 to provide control for a dual system consisting of two separate compressors and evaporators or,
alternatively, two evaporators with one compressor.

Due to the logic in the 'DIGIFROST' controller, it is vital to the operation of the system that, where applicable,
the following parameters on the EWPC 'mother' control should be set as follows -

PARAMETERS IMPORTANT SETTINGS

dSt Defrost Stop temp. Must be set to value of '85' or above

FSt Fan Stop temp. Must be set to value of '85' or above

Important Notes

EPr Evap Probe readout This function is now redundant.

Error messages 'E1' & 'E2' indicating a faulty sensor or connection will no longer appear in the display. If a
fault occurs, the sensor resistances should be checked as per the table shown in 'Installation & Setup
Suggestions' - please refer to page 1.

For additional assistance or guidance on the application of the EWDR975, please contact our Technical
Department.

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

31
 Eliwell Controls - Adverse Condition Protection
In circumstances where a control could be influenced by other local electrical equipment or by an erratic or
spike prone mains supply, it may be prudent to take action to protect the control and thereby the reliable
operation of the system. Generally, these 'safeguards' are very inexpensive and may in some situations be
looked upon as standard procedure where there is any doubt about the quality of the electrical supply or the
effect of associated electrical equipment.

Noise Filter for Inductive coils - part no. PELE342

Inductive coils as fitted, for example, to solenoid valves or contactors can produce a back EMF which can
interfere with the control. This particularly relates to coils directly operated by the control. To minimise the
effect, a noise filter should be fitted in parallel, and as near as possible, to the relevant coil as shown below.

Noise Filter for Mains supply - part no. CON200

Almost all electrical supplies are influenced by the running of other electrical equipment and will carry
some 'noise' or transients. Most normal supplies are however acceptable but where the supply is also used
for large motors, fluorescent lights, etc., the fitting of a mains noise filter is advisable. The filter, as above,
is rated at 1 amp & should be fitted in series to the 240vac supply to the control or transformer. The earth
connection must be made otherwise the filter will not function.

Varistor Voltage Spike suppresser - part no. CON210

Spikes of up to 35 times the normal line voltage are not uncommon and will often either damage or
influence any electronic control. When a poor quality supply is established or suspected, it is practical to fit
a spike suppresser in parallel with the 240vac supply to the transformer or, in the case of 240v instruments,
in parallel with the mains supply.

Set-up for 12v controls Set-up for 240v controls

Information courtesy of Thermofrost Cryo PLC – Copyright September 2000

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