Problem: Half of the upstairs has cold air blowing out of vents; other half has hot air.

Backstory: I have a 19 year old heat pump, Janitrol GV 100-3. 100,000 BTUs, 2.5 ton capacity. There is a heating unit in the attic and the condensor is outside. The heat pump is only for the upstairs of my home, approximately 800 sf.

Two weeks ago, the condensor unit started icing over. A HVAC company changed the defrost thermostat and cleaned the coils in the unit in the attic. The day they came, it was 70 degrees. It stayed warm for a week, so I didn't turn the heat back on. Then the temperatures dropped and I turned the heat on.

The air on the left side of the house blows out cold at the normal rate of air flow. The air on the right side comes out warm at a normal rate of flow. I checked the ductwork and everything appears fine. If I compress the duct, the air flow is reduced. I tried that on all ducts (5 total). The insulation covering the ducts isn't ripped at all. I traced the temperature difference back to the plenum. Where the plenum connects to the heat pump, the right side is warm to the touch, the left side is cold.

Two questions. 1) If I close the vents in the left side of the house, will that force the warm air into the colder rooms from the warmer rooms? It's cold and having cold air blowing in my bedroom is not comfortable. Since it's the weekend and it's cold, I have to do something until they can get back to fix it.

2) What potentially is the problem? Could the HVAC guys have done something when they were cleaning the coils? I'm reluctant to have them back because these people said that I needed new duct work. My duct work is just fine so I know that they are trying to fleece me. I would like to have as much ammunition as possible when they return.

 

Story sounds odd.........Could be a ductwork problem.

I would call another company but do not tell them anything about it being looked at by a competitor.
You may not get an objective opinion if they know they are coming in on the same problem as someone else.

 

Does anyone have an idea what the problem would be?

 

Hmmmm Curious. If you did not have this problem before they came then they need to come back and make it right. Ocassionally, I misjudge a situation and a day later I get a call that it just isnt working right. It gets moved to the top of my list until the customer is satisfied. Just last week, I had to absorb $453 worth of parts because of bad info from my supplier. My customer wasnt happy so I installed new parts to fix it and in the end they will call me back and I will have a new supplier. In this business, its all about the customer. You have leverage, use it.

 

I've been waiting to hear back.