Any HVAC experts?

[wingedfish]

You won't fix it yourself unless you can understand what everything does. Before you had the AC installed the HRV was interconnected to your furnace/airhandler fan. The a/c guys tied into this same system. When your tstat calls for a/c, an inter connection in the tstat brings the air handler fan on also. What is happening to you is it is back feeding so when you turn on the HRV, the a/c turns on as well. This is very bad. To verify if i'm right, turn on your hrv and if the a/c is on, flip the fan switch on the tstat to "on". The a/c should turn off. At best it will cost a boat load of power. At worst it will ruin the compressor. Let the a/c guys know and they will likely fix it up for you.

[Seriak]

Originally Posted by wingedfish

You won't fix it yourself unless you can understand what everything does. Before you had the AC installed the HRV was interconnected to your furnace/airhandler fan. The a/c guys tied into this same system. When your tstat calls for a/c, an inter connection in the tstat brings the air handler fan on also. What is happening to you is it is back feeding so when you turn on the HRV, the a/c turns on as well. This is very bad. To verify if i'm right, turn on your hrv and if the a/c is on, flip the fan switch on the tstat to "on". The a/c should turn off. At best it will cost a boat load of power. At worst it will ruin the compressor. Let the a/c guys know and they will likely fix it up for you.

Well you must be a HVAC installer as you were right. If the fan is going on the a/c unit after I turn on the Air exchanger and I turn the fan from auto to on, the fan does shut off. I am assuming this is a simple fix and it shouldn't cost me very much?

[wingedfish]

I wouldnt be quick to call it simple and cheap is a relative term. It would take me a relay and service call, shy of 200 would be a guess. A reputable company in Calgary would likely be just over 200. A guy that scratches his head lots and lets the smoke out of electronic boards could cost a thousand.

[rayjay]

Do you have any electrician friends? Any experienced electrician should be able to help you out.
However, you now know the fan doesn't go on with the exchanger when the selection is made to "on" instead of "auto" so as long as everything still works correctly when the furnace or AC is working along with the exchanger, just leave the selection where it is.

[wingedfish]

Originally Posted by rayjay

Do you have any electrician friends? Any experienced electrician should be able to help you out.
However, you now know the fan doesn't go on with the exchanger when the selection is made to "on" instead of "auto" so as long as everything still works correctly when the furnace or AC is working along with the exchanger, just leave the selection where it is.

A Psc fan running steady will eat $200 in 3 months with today's power costs.
If you have an ecm motor ( commonly called "DC" or "variable speed" it might take 6 months. Fixing it will be far cheaper.

This is an Hvac issue and we deal with it all the time. The a/c guys should have seen wires and fixed it when they installed it.

[Seriak]

I don't use the air exchanger very often which is why I didnt notice this happening until years after the ac was installed. I just thought it might help my heat differential from top floor to bottom floor in the summer hence how I found out it was doing it.

I may have a look myself and see what is up in there.