# Air exchanger sucking all my heaty goodness



## TJ-Bill (Jan 7, 2009)

We moved into this house last fall.. this will be my second winter burning wood here.. Last year I could hear the air exchanger kicking on everynow and then but paid little mind.. THIS Year how ever it's driving me nutz.. The dial on the wall says OFF, but yet it still comes on. I can hear it sucking air from almost everyroom.

So today I went up in the room /attic whatever you want to call it and checked it out. It appears to small to have a heat re-covery system on it but I'm no expert. 
All I know is that it's 13 years old

Make is a Ventmax Airexchanger
Model VENT-STD
Serial # AAAA49011900811

Anyone know anything about it?

I turned it off.. I think I did the right thing at least for the winter.. In the summer I'll go back up and turn it back on..

Will I do any harm to it letting it freeze during the winter?

Thanks


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## Biker Dude (Jan 7, 2009)

I did a search for your model but got nothing so I'll assume it is similar to all the other HRVs (Heat Recovery Ventilator) and try to answer your questions. They are used to draw fresh air into the house while blowing stale, moist air out of the house. Fresh and stale air cross paths through an air to air heat exchanger which is supposed to warm up the incoming fresh air. I'm sure it works to some extent. If yours is turning on and off it is probably wired to a humidistat which measures the humidity in your home. Humidity and mold formation is a problem in newer air tight homes and HRVs were invented to address that problem. If humidity was your only concern then it would probably be OK to shut it down for the winter if you kept an eye on humidity levels in the house but if you are burning in an indoor stove or fireplace then chances are good that the HRV is providing you with fresh combustion air and turning it off will be a major air quality problem. The choice is yours of course but if it was my house I would try to figure out why the HRV is behaving differently now than it was before. Maybe your humidistat or controller is malfunctioning and needs to be replaced?


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## mtfallsmikey (Jan 8, 2009)

Those things can be a PITA!


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## reaperman (Jan 8, 2009)

Actually, its the summer months where you may want to turn it off. In the summer it will bring in hot, humid air, if you have central air, your air conditioner will be fighting the air exchanger, by trying to rid your home of heat and humidity. The newer control for the modern air exhangers, is a wall switch, which is adjusted by % of the time you want it to run, from 10% to 100%. A switch like this is very easy to install, it is low voltage and runs off thermostat wire. Or a regular .50 wall switch could be wired to it turn it on and off, at your liking.


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## TJ-Bill (Jan 8, 2009)

Few things..

I don't think mine has a heat recovery, the box is to small and the air coming out of the outlets is cold.. I wouldn't be worried about it except for the fact that the dail on the wall (which rated in humidity %) it's set on %0-Off but it still runs constantly when I'm home and have a fire on.

how can I check to see if it has a heat recovery unit on it?. I like the idea about the fresh air coming in feeding the fire.. (even though there's a intake in the basement by the stove). But I always leave the basement window just a crack anyway.

Also.. I have no AC so It's be going on in the summer.. Also I can't see humidity being a huge problem in the winter here.


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## Biker Dude (Jan 9, 2009)

Easiest way to tell if it is heat recovery is to take off the side panel and look inside it. The ones I have seen that are heat recovery have a criss-cross heat exchanger that is about 1 ft. square and made of plastic.

My bath fan is wired to a humidistat and if I turn it to 0% it runs all the time but if I turn it to 100% then it doesn't run at all. Have you tried turning yours to 100% to see what happens?

If you have a combustion air intake by the stove and you keep the window cracked I don't think you will have any problems shutting down the exchanger completely.


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## TJ-Bill (Jan 10, 2009)

I never did turn it to %100 guess that would make sense.

Also in the last few days that the exchanger has been off there has been a noticable difference in the temp of the house in the morning when we get up. 

Normally the house can be quite cold. but in the past few days the teamp has stayed aroound 21-22 degrees(I put the theremometer in the bedroom )


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## reaperman (Jan 10, 2009)

The heat recovery is area is pretty much everything inside of the box, with the exception of the blower fan. In cold weather, cold air does come out of the vents, the recovery has its limits, when its below 0, I turn the unit off, unless the house is too hot from the wood burner, then I can cool it down a bit and get fresh air at the same time.



<a href="http://s474.photobucket.com/albums/rr103/reaperman112/?action=view&current=101_0804.jpg" target="_blank"><img src="http://i474.photobucket.com/albums/rr103/reaperman112/101_0804.jpg" border="0" alt="Photobucket"></a>


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## mike39 (Nov 17, 2014)

hi.I have a vent max air exchanger model100pxdh serial #aaaa49025700345 and I would like to know if it should run all winter.thanks


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## slowp (Nov 17, 2014)

I have what is called a whole house fan. The control is a timer switch. I let it go through the cycles. You do have to remember to turn it off if it is going when you are opening the door of the stove. If you fail to do that, smoke will be sucked into the house. If I wanted to shut it off, I'd take the knob off. That is made to come off so you can adjust the time. The builder of the house said the fan is there to bring in fresh air, not to control humidity. Our climate is cool and wet most of the year.

In each room there is a small vent at the top of the windows. That can be closed off and the fan shut off. I've kept things airy. The wood stove also has an air intake piped into it through the floor. That's something else that must be done in the air tight houses we now have.

Have you looked at your electrical box? Maybe it has a dedicated breaker switch that you could turn off?


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## cantoo (Nov 17, 2014)

Mike, need more info to give you the correct information. Where do you live, etc. Many things determine HRV use. Things like how much moisture you produce in a day, (girls take long showers which produce moisture)whirlpool bath with jets, do you leave a window open, are you in a sheltered location, pets (doggie door which let air in) how old and airtight is your house, type of heating system and on and on.
Where I live here in Ontario our rule is if you have moisture (condensation) on the bottom of your windows on the glass then you need to click it up a notch or two.
This is a picture of the HRV we use in the houses we build. Shameless plug. http://www.royalhomes.com/blog/?attachment_id=177


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## mike39 (Nov 18, 2014)

hi and thanks for your reply.i live in new Brunswick and own a large mini home and we don't have any animals or kids at home but our windows steam up when it's cold but not to much when I leave the vent max on.i wrote to the company but didn't get and answer.help understanding this would be great.thanks again


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## cantoo (Nov 18, 2014)

Leaving near the water and fog make for a very hard to use properly HRV. Whatever is outside will be drawn inside.


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## mike39 (Nov 19, 2014)

thanks but I don't live any ware near water or fog.mike


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## NSMaple1 (Nov 19, 2014)

Just get a humidity monitor & set it on a shelf somewhere & go from there. I have an HRV, set the control in the middle of the humidity range, and it never cuts in in the winter. The monitor I have on the shelf stays in the middle of the green zone all winter - I'm pretty close to you so conditions should be similar. But every house & climate will have it's peculiarities, so gauge your situation with a monitor. I would fully expect you don't need to run it at all in the winter - unless your house is REALLY sealed up tight.

I also wouldn't go by condensation on windows alone - that could also be a sign of a tight house, or at least a tight window, that has no air movement across the window that would stop the condensation from forming. I get some on some windows at certain times even when my humidity is down in the low zone.

(Also sounds like you might not have an HRV, and it's just a simple air exchanger - but opening it up & looking inside would tell for sure. And yes, turning it to 0% would make it run all the time.)


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## mike39 (Nov 19, 2014)

thanks very much.that great


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## cantoo (Nov 19, 2014)

Maple has it right, get the monitor and learn to use it.


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## mike39 (Nov 20, 2014)

thanks well do


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