Any HVAC experts?

[Seriak]

Originally Posted by rayjay

I'm not real clear on this yet. Is the AC fan turning the one in the outdoor unit?
I've not seen an AC motor inside.
If it is the outdoor unit, is it just the fan coming on or is it the fan and the compressor?

The outdoor a/c unit's fan is turning on when I turn on my air exchanger (With the thermostat set to off) but the compressor is not turning on so the air circulating in my house is room temerature.

[tim the toolman]

If you ac is covered in the winter you should be able to just flip The breaker to the ac (should be independant) and the fan will not run. I know this is kind of putting a bandaid on a bullet wound but it should work as a temporary fix if all else fails.
But believe me when I say I am no expert lol

[wingedfish]

Originally Posted by Seriak

The outdoor a/c unit's fan is turning on when I turn on my air exchanger (With the thermostat set to off) but the compressor is not turning on so the air circulating in my house is room temerature.

It is impossible for the condencer fan motor to run without the compressor. It runs on the same contactor. Though there is an internal overload that can shut the compressor down for heat/over amp issues.

[cwatkins]

Originally Posted by wingedfish

It is impossible for the condencer fan motor to run without the compressor. It runs on the same contactor. Though there is an internal overload that can shut the compressor down for heat/over amp issues.

Yep, this is totally accurate.

It sounds like the backfeeding thing as mentioned above. The original intent was to turn the exchanged on automatically when the A/C was run. But the opposite is also true.

You could have already done some serious damage to your A/C condensing unit if you've had the cover on. And besides, it's costing the same amount of money to run it right now as if it was the middle of summer, since the A/C and exchanger are both running at the same time.

I would call in a qualified HVAC person ASAP before any further damage is done.

EDIT: You may need to/want to invest in a good thermostat (I.E. Honeywell Vision Pro) that has a separate programmable output for the exchanger.

[Seriak]

Originally Posted by cwatkins

Yep, this is totally accurate.

It sounds like the backfeeding thing as mentioned above. The original intent was to turn the exchanged on automatically when the A/C was run. But the opposite is also true.

You could have already done some serious damage to your A/C condensing unit if you've had the cover on. And besides, it's costing the same amount of money to run it right now as if it was the middle of summer, since the A/C and exchanger are both running at the same time.

I would call in a qualified HVAC person ASAP before any further damage is done.

EDIT: You may need to/want to invest in a good thermostat (I.E. Honeywell Vision Pro) that has a separate programmable output for the exchanger.

I don't think any damage is done as I have never really used the exchanger. It's on a manual switch which is almost always left off. We actually turned it off right by the furnace for most of it as we had little fingers going around turning on random switches in the house and we didn't want them to turn on the air exchanger. I am just finally realizing that maybe I should use it more and have come accross this problem.

[weyburnt]

Sounds like a wiring issue. Look inside the furnace, there should be 2 wires from the hrv to furnace, 2 from a/c to furnace and 3,4or5 from T stat to furnace. From the hrv to furnace one wire should go from the r terminal and one wire should go to the g terminal. If this wire went to the y terminal by accidient, this is the problem you would have. The wire to the Ac should go from the c terminal and one from the y terminal. If this wire was accidiently ran to the g terminal, same problem would happen. As well if this was the case, Ac would run if you switched the furnace to fan on position.

[Seriak]

It is as you described

[Seriak]

I heard it also may be related to an old tstat. However I have no idea how to tell how old is old.

[weyburnt]

So hrv is going to r and g
Ac is going to y and c
Make sure there is not a jumper wire between y and g
If that checks out look at the back of the t stat make sure there is no jumper on the t stat from y and g. Check the wiring on the back of the t stat. Note the colors going down to furnace and make sure they match up. Ie w-w
R-r and rc if ther is one y-y and g-g

Make sure there is no jumper from the hrv to the furnace. There shouldn't be but some people's children are idiots