Omega VSHYe Series, Installation And Operation Manual, Page: 19 / 31

OMEGA-VSHYe.F-IOM-2108
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Table 8: Troubleshooting Guide
Problem Mode Possible Cause(s) Correction Method
Heating/Cooling Main power off Check unit disconnect switch/ circuit breaker/ fuses
Heating/Cooling Defective control transformer Confirm thermostat is wired correctly before replacing
Heating/Cooling Broken, incorrect or loose connections
Check thermostat wiring. Isolate thermostat. Check for for loose thermostat connections.
Repair and/or tighten as required.
Heating/Cooling Defective thermostat
Check and replace
Unit short cycles Heating/Cooling Thermostat improperly located Relocate thermostat away from supply registers
Cooling Defective compressor overload
Check and replace if required (if external)
Cooling Defective compressor contactor Check and replace if required
Heating/Cooling Supply voltage too low Correct incoming supply voltage setting at Transformer
Cooling Defective compressor capacitor
Check and replace if required
Cooling Defective compressor windings
Check and replace if required
Cooling Limit switches open
Check for faulty pressure switches. Switches are normally closed. Replace if switches are open
when unit is shutdown.
Cooling
Clogged Drain Pan / Condensate hose /
Faulty Sensor
Condensate switch detects overflow condition in drain pan, check for obstruction. If no water,
check switch, replace if required.
Heating/Cooling Dirty filter Check and replace
Heating/Cooling Blower RPM too low Set to blower to higher fan speed
Heating/Cooling
Loss of conditioned air due to ductwork
leaks
Check for duct leaks and repair
Cooling Low on refrigerant charge
Possible leak in system. Check for leaks at piping joints and coil. Repair if possible, and
recharge to unit nameplate charge rating.
Heating/Cooling Thermostat improperly located
Relocate thermostat
Heating/Cooling Inadequate water flow Increase GPM
Cooling Entering Water Temperature too hot Adjust Supply Loop temperature lower
Heating Entering Water Temperature too cold Adjust Supply Loop temperature higher
Cooling Inadequate GPM
If auto shut-off valve is installed, check that control valve actuator opens during call for
Heating. Set valve to manual mode and remove power connections from actuator and re-test.
If manual mode re-test confirms proper water flow, actuator is likely faulty.
Cooling Water too hot
Reduce water loop temperature
Cooling Overcharged with refrigerant Decrease charge/Confirm charge matches nameplate.
Cooling Defective pressure switch Check or replace
Cooling Undercharged
Possible leak in system. Check for leaks at piping joints and coil. Repair if possible, and
recharge to unit nameplate charge rating.
Cooling
Faulty thermal expansion valve (TXV)
operation
Flooding of refrigerant caused by the TX valve not opening/closing correctly. Check TX valve
bulb has not come loose.
Cooling Inadequate air flow
Check blower. Typical airflow should be 400 cfm/Ton across air coil. Check for dirty or
obstructed air coil
Cooling Dirty filter
Check and replace
Water Loop
Discharge Temp
Alarm
Cooling
Inadequate GPM/Too High Riser Loop
Temperature
Leaving water temperature from water coil exceeds acceptable operating temperature. Check
for clogged or faulty water components, or too low GPM riser supply or too high entering water
temperature.
Water Loop
Supply Temp
Alarm
Cooling Too High Riser Loop Temperature
Entering water temperature to water coil exceeds acceptable operating temperature. Lower
riser water loop temperature.
Condensate
Overflow Alarm
Cooling Clogged Drain Pan / Condensate hose
Condensate switch detects overflow condition in cabinet drain pan. Check for plugged,
obstructed or pinched condensate hose.
Cooling Suction Temperature sensor defective.
Check that sensor is not open or closed. Check for resistance, if reading Zero of Infinity
replace sensor.
Cooling Suction Temperature below threshold
Suction temperature is below 50
o
F in cooling and 70
o
F in heating. Refer to possible causes
under "Low Pressure Fault".
Refrigerant
Suction Alarm
No response to
any thermostat
setting
Insufficient
capacity
High Pressure
Fault
Low Pressure
Fault
Only blower runs,
but not
compressor