COLDROOM

System Standard Operations

SYSTEM turned On
I. On/Off Switch Close
a. If door close include ‘IV – a’
b. If THERMOSTAT close include ‘II – a’

TMEP > SP – require Cooling

II. When Thermostat Close
a. C2 coil energise, C3 coil energise
C2-1 (N/O) Close, C3-1 (N/O) Close
Comp. Lamp+Motor On, Cond. Fan Lamp+Motor On

TMEP < SP – n/ require Cooling

III. When Thermostat Open
a. C2 coil de-energise, C3 coil de-energise
C2-1 (N/O) Open, C3-1 N/O) Open
Comp Lamp+Motor Off, Cond. Fan Lamp+Motor Off

Door Shut
IV. Door Switch (N/O) Close
a. C3 coil energise
C3-1 (N/O) Close
Evap. Lamp+Motor on

Door Ajar
V. Door Switch (N/O) Open
a. C3 coil de-energise
C3-1 (N/O) Open
Evap. Lamp+Motor Off
Component Fault Table
Component Fault Operation condition
O/C C/C
On Switch * Noting Happens
* Operates as normal - will n/ stop
Thermostat * Comp. + Cond. (light and motor) n/ run
* Comp. + Cond. (light and motor) run under SP
HP Safety * Comp. n/ run
* Comp. run all time (high pressure above lim.)
LP Safety * Comp. n/ run
* Comp. run all time (low pressure below lim.)
Door Switch * Evap. (light and motor) n/ run (door closed)
* Evap. (light and motor) run (door open)
Contactor 1 * Comp. (light and motor) n/ run (C1 energised)
* Comp. (light and motor) run all time ( ot, LP,HP - O/C)
coil * Comp. (light and motor) n/ run
Contactor 2 * Cond. (light and motor) n/ run
* Cond. (light and motor) run (ot - O/C)
coil * Cond. (light and motor) n/ run
Contactor 3 * Evap. (light and motor) n/ run
* Evap. (light and motor) run (door open)
coil * Evap. (light and motor) n/ run
Diagnostic Guidelines

Condition 1
Check supply Voltage
→ if supply n/ available – rectify and retest
→ if supply available
→ Test On Switch: Replace if faulty

Condition 2
Test Thermostat
→if O/C when Temp above SP - replace Thermostat

Condition 3
Check Contactor 3 operation

→if C3 n/ pull in during operation;

→Test Door Switch: Replace Door Switch

→Test C3 Coil for O/C: Replace C3

→if C3 pull in

→Test Voltage drop across contacts: Replace C3

Condition 4
Check Contactor 2 Operation

→if C2 pull in

→Test Voltage drop across contacts: Replace C2

→if C2 n/ pull in

→Test C2 Coil for O/C: Replace C3

Condition 5
Check C1 Operation

→if C1 pull in

→Test Voltage drop across contacts: Replace C1

→if C1 n/ pull in

→Test HP, LP and C1 Coil: replace if Faulty

Condition 6
Fault test system;

→if system n/ stop w/ On Switch: Replace On Switch

→if HP or LP n/ stop Comp.: Replace

→if Thermostat n/ stop Comp. and Cond. Fan: Replace

→if Door Switch n/ stop Evap. Fan: Replace

AIR CONDITIONER

System Standard Operations

System turn on

i. On/Off Switch close

C1 energise
Evap. Fan On
if V/C switch close include ‘ii.’
Air-conditioning required
ii. When V/C Switch close
if Cooling select include ‘iii.’
otherwise
if Heating select include ‘iv.’
Cooling selected
iii. When cooling switch closed
Cooling lamp On
and
if Return temp. > SP include ‘v.’
Heating selected
iv. When heating switch closes
Heat lamp on, RV lamp on
and
if Return Temp. < SP include ‘v.’
Compressor call
v. Thermostat close
C2 energised
Comp. On
Compressor n/ call
vi. When thermostat open
C2 de-energised
Comp. Off
Component Fault Table

Component Fault Operation Condition

C/C O/C
On/Off * System run constant
* System n/ run
Vent/Condition * Cool or Heat lamp constant
* Comp, RV, Heat and Cool lamp n/ run
Cool
Cool/Heat O/C Comp., Cool lamp n/ run
Heat
O/C Comp., Heat lamp and RV n/ run
Cool
Thermostat O/C Comp n/ run - Cooling
Heat
O/C Comp n/ run - Heating
HP Switch * Comp. run pressure above lim.
* Comp n/ run
LP Switch * Comp. run pressure below lim.
* Comp. n/ run
TOL * Comp. run high current
* Comp. n/ run
Oil Pressure * Comp. run low oil pressure
* Comp. n/ run
Evap. Contactor * Evap. run constant
* Evap. n/ run
Coil * Evap. n/ run contactor deenergised
Comp. Contactor * Comp. run when Temp >SP(HEAT) <SP(COOL)
* Comp. n/ run
Coil * Comp. n/ run
Diagnostic Guidelines
Condition 1
Test supply Voltage

→if supply n/ available – rectify and retest

→if supply available – test On Switch: Replace if faulty

Condition 2
Test Vent/Condition switch and Thermostat

→Replace if faulty

Condition 3
Test Heat/Cool Switch and Thermostat

→Replace if faulty

Condition 4
Test Heat/Cool Switch and Thermostat

→Replace if faulty

Condition 5
Test Heat/Cool Switch and Thermostat

→Replace if faulty

Condition 6
Test Heat/Cool Switch and Thermostat

→Replace if faulty

Condition 7
Check C1

→Test C1 Coil for O/C – Replace if faulty

→Test C1 Contact for O/C – Replace if faulty

Condition 8
Check C2 Operation

→C2 pull in

→Test contact for O/C – Replace if faulty

→C2 n/ pull in

→Test LP/HP, TOL, OIL and C2 coil for O/C – Replace if faulty

Condition 9 - Short circuit fault

Action On switch

→if system n/ stop w/ On Switch: Replace On Switch

→if lamp turn off but Comp. or Evap. Motor runs replace contactor
If system cycles with Switch test safeties

→if HP/LP n/ stop Comp.: Replace

→if TOL n/ stop Comp.: Replace

→if OIL n/ stop Comp.: Replace

→V/C n/ stop Comp.: Replace

CHILLER
System Standard Operations
SYSTEM turned On

I. On/Off Switch close

T1 coil energise, CWP coil energise,
T1 begin delay count, CWP-1 (N/O) Close, CWP-2 (N/O) Close
CWP Lamp+Motor On
CWF Switch Close
II. T1 times out
T1-1 N/C Opens, T1-2 N/O close
if CWRT Close include ‘III.’
CWP coil remain energise - see CWFS
CWP Lamp+Motor On → until power cycle

Chilled Water Temp > SP – Cooling required

III. When CWRT CLOSE

R1 coil energise
R1-1 (N/O) Close, R1-2 (N/O) Close
T2 coil energise, HWP coil energise
T2 begin delay count, HWP-1 (N/O) Close, HWP-2 (N/O)
Close
HWP Lamp+Motor On
HWF Switch Close
T2 Times out
T2-1 (N/C) Open, T2-2 (N/O) Close
CH coil energise
CH-1 (N/O) Close
CH Lamp+Motor On
if HWRT Close, then include ‘V.’

Chilled Water Temp < SP – Cooling n/ required

IV. When CWRT OPEN

R1 coil de-energise, begin delay open count
R1-2 (N/O) Open
CH coil de-energises
CH-1 (N/O) Open
CH Lamp+Motor Off

Delay open time out – R1-1 (N/O) Open

CTF coil, HWP coil, T2 coil deenergise

CTF-1 (N/O), HWP-1 (N/O), HWP-2 (N/O), T2-2 (N/O) Open, T2-1 (N/C) Close

CTF, HWP Lamp+Motor Off

 Condenser Water Temp High

V. When HWRT (N/O) Close

CTF coil energise
CTF-1 (N/O) Close
CTF Lamp+Motor On

Condenser Water Temp Low

VI. When HWRT Opens

CTF coil deenergise

CT-1 (N/O) Open

CTF Lamp+Motor Off

Component Fault Table

Components C/C O/C Fault

HP Switch * Chiller run pressure above HP
* Chiller n/ run
LP Switch * Chiller run pressure below LP
* Chiller n/ run
TOL * Chiller run high current
* Chiller n/ run
On/Off * N/ turn off
* N/ turn on
CWF Switch * CWP run without flow
* CWP stop after Timer 1
HWF Switch * HWP run without flow
* HWP stop after Timer 2
CWR Thermostat * Chiller and HWP run constant below SP
* Chiller, HWP and CTF n/ run
HWR Thermostat * CT Fan Run, w/ CH
* CT Fan n/ run
Timer 1 * Nothing happens
* HWP, CH, CTF n/ run
coil * HWP, CH, CTF n/ run
CWP Contactor * CWP run constant
* CWP n/ run
coil * CWP n/ run
Timer 2 * CH, CTF n/ run
* HWP, CH, CTF n/ run
coil * HWP, CH, CTF n/ run
HWP Contactor * HWP run constant
* HWP, CH, CTF n/ run
coil * HWP, CH, CTF n/ run
Chiller Contactor * Chiller run constant
* Chiller n/ run
coil * Chiller n/ run
CTF Contactor * CTF run constant
* CTF n/ run
coil * CTF n/ run
Relay timer * HWP and CH n/ turn off
* HWP, CH, CTF n/ run
coil * HWP, CH, CTF n/ run
Diagnostic Guidelines
Condition 1
Check CWFS

→O/C

Condition 2
Check HWFS

→O/C

Condition 3
Check T2 operation

→Coil burnout

→O/C Contact

Condition 4
Test HWRT

→if HWRT O/C – Faulty

→if C/C – CTF test coil and contact

Condition 5
Test Supply Voltage

→No voltage – Rectify and retest

→Test On switch for O/C

Force CWFS close, Confirm CWP contact operation

→CWP not operate – test CWP – Coil burnout

→CWP operate

→Test CWP contact for O/C

→Test N/C for O/C

Condition 6
Check CH contactor operation

→Operate – test CH contacts for O/C

→n/ Operate

→Test LP, HP, TOL, CH coil, R1-1 for O/C

Condition 7
Test

→T1 N/O Output – Coil or O/C

→CWRT w/ high temperature

→ R1 coil burnout

→R1-1 N/O for C/C

→CWP-2

→T2 N/C for O/C

→T2 N/O for O/C

→T2 operation – coil

→ HWP operation

→HWP for O/C

Condition 8 - Short Circuit Fault

CH C/C

CTF C/C

CWF C/C

CWP C/C

CWRT C/C

HP Switch C/C

HWFS C/C

HWP C/C

HWRT C/C

LP Switch C/C

On/Off C/C

Relay timer C/C

TOL C/C
Fault Condition Table - Coldroom

Obesvations
Fault Comp. Run Comp. Not Run Cond. Fan Run Cond. Fan Not Run Evap. Run Evap. Not Run Condition
On/Off O/C * * * 1
Thermastat O/C * * * 2
Door Switch O/C * * * 3
C3 O/C * * * 3
C3 Coil Burnout * * * 3
C2 O/C * * * 4
C2 Coil Burnout * * * 4
HP O/C * * * 5
LP O/C * * * 5
C1 O/C * * * 5
C1 Coil Burnout * * * 5
On/Off C/C * * * 6
Thermastat C/C * * * 6
HP C/C * * * 6
LP C/C * * * 6
Door Switch C/C * * * 6
C1 C/C * * * 6
C2 C/C * * * 6
C3 C/C * * * 6
Fault Condition Table – Air conditioner
Obesvations
Fault Comp. Run Comp. Not Run Cooling Lamp Work Cooling Lamp Not Work Heat/RV Lamp Work Heat/ RV Not Work Evap. Run Evap. Not Run Condition
On/Off O/C * * * * 1
Vent/Con. O/C * * * * 2
Heat O/C Cool Heat * * * 3
Cool O/C Heat Cool * * * 4
Thermostat Cool O/C Heat Cool * * 5
Thermostat Heat O/C Cool Heat * * 6
C1 O/C * * * * 7
C1 Coil burnout * * * * 7
HP/LP O/C * * * * 8
TOL O/C * * * * 8
OIL O/C * * * * 8
C2 O/C * * * * 8
C2 Coil Burnout * * * * 9
On/Off C/C * * * * 9
Vent/Con. C/C * * * * 9
HP/LP C/C * * * * 9
TOL C/C * * * * 9
OIL C/C * * * * 9
C1 C/C * * * * 9
C2 C/C * * * * 9
Fault Condition Table - Chiller
OBSERVATION
FAULT CH run CH s/s CH n/ run CTF run CTF s/s CTF n/ run HWP run HWP s/s HWP n/ run CWP run CWP s/s CWP n/ run Condition
CWF O/C * * * * 1
HWFS O/C * * * * 2
T2 O/C * * * * 3
Timer 2 coil * * * * 3
CTF O/C * * * * 4
CTF Contactor coil * * * * 4
HWRT O/C * * * * 4
T1 C/C * * * * 5
CWP Coil * * * * 5
CWP O/C * * * * 5
On/Off O/C * * * * 5
TOL O/C * * * * 6
CH O/C * * * * 6
Chiller Contactor coil * * * * 6
HP Switch O/C * * * * 6
LP Switch O/C * * * * 6
CWRT O/C * * * * 7
HWP O/C * * * * 7
HWP Contactor Coil * * * * 7
Relay timer O/C * * * * 7
Relay timer coil * * * * 7
T1 O/C * * * * 7
T1 coil * * * * 7
T2 C/C * * * * 7
CH C/C * * * * 8
CTF C/C * * * * 8
CWF C/C * * * * 8
CWP C/C * * * * 8
CWRT C/C * * * * 8
HP Switch C/C * * * * 8
HWFS C/C * * * * 8
HWP C/C * * * * 8
HWRT C/C * * * * 8
LP Switch C/C * * * * 8
On/Off C/C * * * * 8
Relay timer C/C * * * * 8
TOL C/C * * * * 8