FIGURE 13 Continued. TROUBLESHOOTING GUIDE
COMPRESSOR STARTER
OVERLOAD TRIPPED
HUNTING
COMPRESSOR
WILL NOT LOAD
COMPRESSOR
WILL NOT UNLOAD
CANNOT RESET
CONTROL CIRCUIT
MOTOR
PRESS
1. Motor circuit problem.
2. Overload relay calibration.
3. Current limit set too high
in control module.
4. Faulty current transformer (C.T.).
5. Single phase.
1 Capacity control vane speed.
2. Fast pulse rate (control module).
3 Faulty expansion valves
4. Fluctuating evaporator water flow.
5. Low refrigerant charge
6. Low condenser water temperature
1. Faulty control module
2. Shorted sensor circuit (chiller)
3. Open sensor circuit (Templifier).
4. Wrong module jumper con-
nections.
5. Defective SB solenoid coil
6. Loss of CT voltage.
7. SB needle valve closed/
restricted.
8. Faulty relay R4.
9. Low refrigerant charge.
10. Vane seal leakage.
11. Faulty LPO switch.
1. Open sensor (chiller)
2. Shorted sensor circuit (Templifier).
3. Faulty control module.
4. Defective SA solenoid coil.
5. Faulty 4-way valve.
6. SA needle valve closed/restricted.
7. Vane damage
8. Wrong module jumper connection.
1. Faulty relays R1 R2, R5, R7.
1. Check continuity.
2. Setting, dashpot o i l level.
3a. Check resistor setting a
b. Check module setting
4. Secondary output
5. Fuses
1 Vane operation.
2. Measure pulse rate.
3. Observe suction pressure
4. Evaporator pressure drop
5. Superheat, subcooling
6. Measure temperature.
1 a. Check + 20 & + 6.2 VD
b. Check load action
2. Remove one sensor lead
3. Jumper COM & ISA.
4. Verify connections.
5. Solenoid action
6. Measure at 1WHT & 3B
7. Open wide.
8. Check relay
9. Superheat.
IO. Mechanical action.
Il. Check switch junction.
1. 6.2 & ISA
2. Remove one sensor lead.
3a. Check + 20 & + 6.2 VD
b. Check load action
4. Check solenoid action.
5. Valve operation.
6. Open wide.
7. Mechanical action
8 Verify connections
1. To check relays, energizt
power and on/off switch t
Install each relay in R7 b
FAIL light should glow. P
RESET button. EXT FAIL
should go out and stay o
relay is faulty.
1. Contact McQuay Service.
2. Reset, add dashpot oil.
3a. Reset.
b. Recalibrate control module.
4. Replace.
5. Correct fault.
1. Reset vane speed needle valve
2. Adjust to slower rate.
3. Repair, replace.
4. Correct flow deficiency.
5. Adjust refrigerant charge
6. Adjust tower controls.
la. Replace module.
b. Replace module.
2. If compressor loads, replace
sensor.
3. If compressor loads, replace
sensor.
4. Correct pin connections.
5. Replace.
6. Reset or replace
7. Clean and reset.
8. Replace
9. Adjust charge.
10. Call McQuay Service.
11. Replace.
1.
If compressor unloads, replace
sensor.
2. If compressor unloads, replace
sensor.
3a. Replace module.
b. Replace module.
4. Replace
5. Repair, replace.
6. Clean, reset.
7. Call McQuay Service.
8. Correct pin connections.
1. Replace faulty relay.
Page 22 / IM 307
