Troubleshooting
44
SS-SVX002B-EN
Condenser Pressure Too High (cont.)
d. Condenser fan not operating.
Check pressure/temperature operating
switches and motor. Replace as needed.
e. Control pressure set too high
Adjust setting to obtain correct pressure.
f. Water/glycol temperature too high.
Check flow and operation of drycooler.
g. Flow of water/glycol too low.
1. Check glycol solution level and
concentration.
2. Valves not open or partially open. Repair or
replace as needed.
3. Air in system - bleed system.
4. Check all strainers and clean if needed.
h. Water/glycol solution not mixed prior to
adding to system.
Remove solution and premix. Refill system.
Condenser Pressure too Low
a. Loss of refrigerant (indicated by bubbles in
sight glass).
Locate and repair leak. Recharge system.
b. Condenser fan controls not set properly.
Adjust or repair controls.
c. Control pressure set too low.
Readjust to 440 psig.
Noisy Compressor
a. Expansion valve stuck in open position
(abnormally cold suction line).
Ensure feeder bulb is tight on suction line. Check
operation and superheat.
b. Worn or scarred compressor bearings.
Replace compressor.
c. Liquid slugging.
System overcharged. Reclaim excess
refrigerant.
d. Scroll compressor not properly phased.
Phase correctly at main power source.
Do not rewire compressor.
Compressor Fails to Start
a. Temperature set point too high.
Adjust to desired temperature.
b. Compressor internal protector is open.
Check compressor for short circuit or ground.
c. Complete loss of refrigerant charge (low
pressure safety switch).
Locate and repair leak. Recharge system.
d. Condenser pressure too high (high pressure
safety switch).
Check condenser for obstructions.
e. Minimum off time has not expired.
Wait for time to expire.
System Short of Capacity
a. Low refrigerant (indicated by bubbles in sight
glass).
Check for leaks. Repair and recharge system.
b. Expansion valve stuck or obstructed (short
cycling or continuous running).
Remove valve and clear obstruction or replace
valve.
c. Clogged drier/strainer (feels cold).
Replace with new drier/ strainer.
d. Reduced airflow.
Check fan speed setting, filters and evaporator
coil.
Compressor Short Cycles
a. Low line voltage causing compressor to
overheat.
Check power source for cause of low line
voltage.
b. Dirty or iced-over evaporator coil.
Defrost and/or clean coil.
c. Reduced airflow.
Check air filters and supply fan speed setting
(when applicable).
d. Lack of refrigerant.
Check for leak. Repair and recharge system.
e. Short circuiting of conditioned air.
1. Supply and/or return grilles are incorrectly
oriented. Reorient grilles.
2. Supply and return grilles are too close
together. Move further apart.
3. Insufficient heat load. Add temporary heat
load to compensate.
f. Return temperature sensor is improperly
located.
Check for supply registers that may be too close
to the return temperature sensor. Relocate
sensor if necessary.
Water- Water/Glycol Valve Fails to Open or Close a. Temperature set point too high or too low.
Adjust temperature setting.
b. No control power to the valve.
Valve actuator wiring is faulty. Check wiring
against schematic and rewire if necessary.
Table 7.
Troubleshooting (continued)
SYMPTOM
PROBABLE CAUSE
RECOMMENDATION
