Water to Air Troubleshooting Tips Troubleshooting Problem/Issue Possible Cause Actions and Corrections Entire unit will not run. Power supply is off Apply power and close disconnect. Circuit breaker reset circuit breaker. Voltage supply low If voltage is below minimum voltage specified on unit data plate, contact local power company. Thermostat Set the fan to On. The fan should run. Set thermostat to Cool and lowest temperature setting, the unit should run in the cooling mode. Set unit to Heat and the highest temperature setting, the unit should run in the heating mode. If neither the blower nor compressor run in all three cases, the thermostat could be wired incorrectly or faulty. To ensure correct wiring or faulty thermostat verify 24 volts is available on the low voltage terminal strip between "R" and "C", "Y" and "C", and, if in cooling mode, "O" and "C". If the blower does not operate, verify 24 volts between terminals "G" and "C". Replace the thermostat if defective. Problem/Issue Possible Cause Actions and Corrections Blower operates but compressor does not. Wiring Check for loose or broken wires at compressor, capacitor, or contactor. Safety controls Check Smart Relay screen for faults. Capacitor Check capacitor and replace if defective. Compressor overload open If the compressor has cooled down and the overload will not reset, replace compressor. Compressor motor grounded Internal winding grounded to the compressor shell. Replace compressor. If compressor burnout has occurred, install suction filter dryer. Compressor windings open After compressor has cooled, check continuity of the compressor windings. If the windings are open, replace the compressor. PLC reads High Discharge pressure Pressure Check Unit too high Or HARD LOCKOUT HI PRESSURE In Cooling mode, check: • Lack of or inadequate water flow • Entering water temperature too warm • Scaled or plugged condenser In Heating mode check: • Lack of or inadequate air flow • Blower is inoperative, clogged filter or restrictions in ductwork Refrigerant charge The unit is overcharged with refrigerant. Reclaim refrigerant, evacuate and recharge with factory recommended charge. High pressure Check for defective high pressure switch. Problem/Issue Possible Cause Actions and Corrections PLC reads: Low Pressure Check Unit, or HARD LOCKOUT LOW PSI. Suction pressure too low In Cooling mode, check: • Lack of or inadequate air flow • Entering water temperature too cold • Blower is inoperative, clogged filter or restrictions in ductwork In Heating mode check: • Lack of or inadequate water flow • Entering water temperature too cold • Scaled or plugged condenser Check refrigerant charge. Always charge to nameplate. Refrigerant charge The unit is low on refrigerant. Check for refrigerant leaks. Repair, evacuate and recharge with factory recommended charge. Low pressure switch Check for defective low pressure switch. Unit Short Cycles Insufficient cooling TXV Bulb may be defective/severed, TXV valve stuck shut, or moisture in the refrigerant system TXV bulb and TXV control diaphragm can be replaced after removing the charge, replacing the control device and bulb, and properly recharging the unit to nameplate value. Unit oversized Recalculate heating and or cooling loads. Thermostat Thermostat may be installed near an area with too much air movement. Relocate or adjust grills Wiring and controls Loose connections in the wiring or a defective compressor contactor. Unit undersized Recalculate heating and or cooling loads. If excessive, adding insulation and shading may possibly fix the problem. Reversing valve Defective reversing valve creates a bypass of refrigerant from discharge to suction side of compressor. Replace reversing valve. Problem/Issue Possible Cause Actions and Corrections Insufficient heating Loss of conditioned air by leaks Check for leaks in duct work or look for entering ambient air through doors or windows. Airflow Lack of adequate air flow or improper distribution of air. Replace dirty filter. Refrigerant charge Low refrigerant charge causing poor operation. Compressor Check for defective compressor. If discharge is too low and suction pressure is too high, compressor is not pumping properly. Replace compressor. Reversing valve Defective reversing valve creates a bypass of refrigerant from discharge to suction side of compressor. Replace reversing valve. Operating pressures Compare unit operating pressures to a pressure / temperature chart for the refrigerant used. TXV Check TXV for restriction or defect. Replace if necessary. Moisture, noncondensables The refrigerant system may be contaminated with moisture or noncondensables. Reclaim refrigerant, evacuate and recharge with factory recommended charge. NOTE: A liquid line dryer may be required. Loss of conditioned air by leaks Check for leaks in duct work or entering ambient air through doors or windows. PLC Reads: HARD LOCKOUT FLOW SWITCH Inadequate or no water flow Check for water flow. Check flow switch by temporarily bypassing it. Make sure all air is purged from lines. Make sure flow center is purged and functional. Check for proper flow direction. PLC Reads: HARD LOCKOUT PAN LEVEL Pan level switch Check condensate drain for blockage. Make sure condensate drain is properly installed. Check Pan level switch by temporarily bypassing it. Make sure unit is on a level surface. PLC Reads: HARD LOCKOUT CURRENT SENS Current sensor Refer to blower operates but compressor does not. Check current sensor by temporarily bypassing it.
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