Friday, 4 February 2022

Stuck Reversing Valve?

Hello Everyone.

I have this weird issue. I am planning on getting an HVAC company service my heat pump condenser unit, however, I want to get your opinion on what may be wrong prior to that.

I got a 5 Ton, 16 year old heat pump unit. I own the house for 7 years. Within those years, the heat pump unit did not caused me much trobule except from replacing capacitors and replacing the blower fan motor once. The house is in the south so we do not get extreme cold here but when we do, the heat pump condernser starts to act up. This issue happens once the temperature goes below 25F ish. Here is what happens.

Here are how and where I am measuring temperature with several probes in the house:
o Outdoor Temperature near the heat pump condenser...lets call it outdoor temp.
o Indoor Temperature in a common room.....indoor temp.
o Blower temperature where the probe is located in the air flow after the coils and before the blower fan.....we will call it blower temp.

****Note, for the following scenario, the emergency heat is not used. The emergency heat strip is disconnected from the power so even though the thermostat may energize it, it will not come on****
1. HVAC System is off. Outdoor temp is 25F, indoor temp is 60F, and blower temp is 58F.
2. The weather conditiions are dry and cold. The heat pump condenser is dry.
3. I turn on the system. Set the thermostat desired temperature to 75F.
4. I hear the blower and condenser turns on. I let the system run for 10 minutes or so and take readings on temperature.
5. Outdoor temp is 25F, indoor temp is 60F, and blower temp is 55F. As you can see, the blower temperature dropped while indoor tempeature did not change. Even though the condenser is working, there is no heat on the coils and blower temp drops couple degrees due to wind chill effect.
6. I shut the system off.
7. I get couple bucket of hot water and dump it on the heat pump condenser specifically targetting the compressor and reversing valve.
8. I turn on the system back on. Set the thermostat desired temperature to 75F same as before.
9. Within a minute, I see the blower temperture rising.
10. After couple of minutes running the system, temperatures are now: 25F, indoor temp is 60F, and blower temp is 78F.
11. The house starts to warm up.

Now, based on the above, I am thinking that I may be dealing with a stuck reversing valve. Heating the valve with hot water releases it and the heat pump statars flowing the refrigerant in the right direction. But then, based on what I read, the normal mode of the valve, when the system is not on, should be heat mode right? What do you think I am dealing with here? Is there something else perhaps blocking the flow of refrigerant until I warm the consenser up just a bit by pouring hot water on it?


source https://hvac-talk.com/vbb/threads/2236180-Stuck-Reversing-Valve?goto=newpost

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