Heating, Air Conditioning, Fridge, HVAC/coil hvac unit in a condo


QUESTION: I'm using a coil water based hvac system in my condo (building has boiler and delivers water through pipes). The unit is relatively new, clean coils, no leaking- ca 3 years old. Suddenly one day, it stopped blowing hot air. The unit does respond to thermostat (different speeds, fan works great), just no matter what temperature I put, it still blows lukewarm and cold air. I thought it might have been a synchron motor but pipes on both sides are hot, yet coils are cold. There's valve connecting pipes to coils, does it has anything to do with it? Should I depressurize it, if so how, what tools?


ANSWER: Hi Eva, It sounds like the the control valve is bad or the coil is air locked. See if you can find the the air vent. There should be a Manuel vent port. It will be located near the coil. Send me a picture if you can.

---------- FOLLOW-UP ----------

QUESTION: I have manually moved the lever on the valve motor to open position and now coils are hot and it blows hot air. I'm wondering is this permanent solution or it's going to go back to where it was? It seems that the synchron motor (see picture right low corner) was working, but might have jammed, and if so, what could have caused that? Do you have other suggestions?

Eva, thanks for the pic. There could be several reasons why the valve isn't working. The motor on the valve could be bad. The round silver thing strapped to the copper pipe is a thermostat. This prevents the valve from opening if there is no hot water. It could be stuck open. If you can use a Voltmeter, I could walk you through it. Let me know.

Heating, Air Conditioning, Fridge, HVAC

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Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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