A mate has a york heat pump which seems to be stuck on cooling. The model is moh25r15aic
Its a 7 kw system. Whats likely to be to problem? Any help out there? Thanks

Marcus Miller
Dear John,
Thank you for writing. If could be a defrost board or a defrost temperature sensor. Might also be a reversing valve, thermostat or relay. We need a HVAC service person to trouble shoot it on site.
Asa Strong

The compressor and fan are running, seems heat ex ipipes are cold not warm. We were thinking control board or 4 way valve thing. Whats the coil on the 4 way do? Does it work all the time?

Marc Miller
Dear John:
To be safe an electrician should work with the electricity. It will void a warranty if there is one if a non licensed person works on the electrical. The coil on the reversing valve is basically an electro magnet. When the control board sends an electrical signal to it then it energizes the coil and a plunger moves the valve to reverse the flow of freon. Some are normally in heat only and have to be energized to cool and some are in cool normally and have to be energized to put the heater in the heat mode. If the coil is burnt out the valve won't move it will keep the heater in cool or heat only. Maybe even stuck between the two. Some times the coil is energized by a defrost thermostat so that it goes into cool for a while to get the ice off the outside coils and that happens when you are trying to heat the pool in cold weather. That doesn't apply to most heaters though. It still could be a digital board or there could be a relay that brings the reversing valve coil on. This should be easy stuff to figure out for an electrician or A/C heating guy if they are paying attention.
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