Anyway to "trick" variable speed air handler

fgastonNovember 5, 2012


I've converted to pellet stoves and want to use my attic air handler to circulate heat thru bedrooms. I'm told by FirstCo, the air handler mfg, as well as HVAC contractor when you have unit on continuous fan only, there is no way to regulate the variable speed fan and it will only run at 50% of speed of heat setting (500-600cfm) which isn't enough.

Anyone have any ideas for rewiring to force the air handler to run at a higher CFM?

Can I replace the variable motor with non-variable, or would the cost be prohibitive?

Lastly, if I'm out of luck, do the thru the wall fans you can buy do the trick?

Thanks, Fred

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Do you have a condensing unit outside? Why not just turn the power off to the condensing unit and still turn the thermostat to cool? The fan should ramp up into high speed just like its trying to cool the house but with no power to the outdoor unit, you'll have no cooling...just high speed air circulation.

Hope this helps

    Bookmark   November 5, 2012 at 9:36PM
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That's an interesting suggestion and worth a try as an experiment. I don't like the idea of swapping out a nice VS blower motor.

You might contact your dealer to see if var speed blower speed in fan on position can be adjusted to high speed.Not something you could do but perhaps a good tech could.


    Bookmark   November 6, 2012 at 6:24AM
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I do have a condensing unit & boiler hooked to unit, and can turn power off for both & see if fan ramps up. As long as not doing any damage...if I can't get the temperature balanced between the spaces with this air handler, I will install thru the wall fans.
Thanks, Fred

    Bookmark   November 6, 2012 at 11:53AM
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OK, so I tried the suggestion of turning on heat (with boiler turned off) & it did in fact ramp up the fan. Interestingly, even after blocking off all returns except the one bringing hot air from the room with pellet stove, and it only raised temp in bedrooms by a degree or two (when I measured air coming out of vents in bedrooms it was 4-5 degrees cooler than air above pellet stove). Guess by the time it runs through all the ducts it really cools off. Think I'm going to go with the thru the wall fans instead. Fred

    Bookmark   November 7, 2012 at 6:15PM
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If the pellet stove is in the basement and the basement isn't insulated you will not have much luck. If the pellet stove is in the actual living space then leaving bedroom doors open and running some fans to circulate will help. Try circulating the coolest air towards the stove.

    Bookmark   November 7, 2012 at 8:28PM
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OP, are you going to install powered Jump ducts like the Tjernlund?

    Bookmark   November 8, 2012 at 2:09PM
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Ionized: I looked into Tjernlund jump ducts but reviews said they don't move enough air & are ineffective so I ordered Broan 380cfm fan and will report back.

countryboymo: pellet stove(s) are in the living space, but leaving bedroom doors open and running air handler to circulate hot air hasn't made any difference in bedroom temp.

Thanks, fred

    Bookmark   November 13, 2012 at 2:49PM
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