Rear zone (heater) also runs AC blower ? - Printable Version

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+--- Thread: Rear zone (heater) also runs AC blower ? (/showthread.php?tid=8283)

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Rear zone (heater) also runs AC blower ? - Gem930 - 12-09-2024

I’m not sure if this is a problem or the way it’s supposed to work, but the rear AC blower motor runs when I turn on the rear aqua hot zone.  The radiator under the bed starts to pump out heat but the blower motor starts up too and makes it uncomfortable, because the blower motor is making it drafty.  Is this correct? Is there another radiator that is not working?  Or is there something wrong with my thermostat?  I feel like there might be another radiator I don’t know about because the front thermostat controls at least two radiators and the rear appears to only control one. Anyone know???

Thx

Gregg

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RE: Rear zone (heater) also runs AC blower ? - Trainer - 12-09-2024

Morning Gregg, call me.
Rudt Legett. 7 one 3. 8 one 8. 3234

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RE: Rear zone (heater) also runs AC blower ? - Richard - 12-09-2024

What kind of AC do you have ? Roof top or basement SCS?

And can you take a pic or describe the source of the drafty air?

No two Newells are alike, so what may be perfectly clear to you looking at it, may require more detailed explanation on the forum.

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RE: Rear zone (heater) also runs AC blower ? - Gem930 - 12-09-2024

Thanks Richard,
It is a basement SCS unit. The draft is created due to the high flow AC blower unit turning on when I turn on the heat portion of the thermostat. The front thermostat does not do this when I turn heat on. To simplify this explanation when I turn the rear heat on I get hot air from the below the bed radiator and room temp air from the AC vents which is causing the drafty feeling. The air from the AC vents which blows (blower motor only) is not air conditioned it is just room temp. The AC compressors do not turn on, just the blower. After talking with Rudy, it sounds like my rear thermostat may be bad. I’m going to switch the front and rear thermostats and see if the problem moves to the front.

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RE: Rear zone (heater) also runs AC blower ? - Richard - 12-09-2024

So……………

The Aquahot gets its signal from the W terminal on the tstat. The AC blower motor gets its signal from either GL or GH, usually black and green. The compressors get their signal from Yellow and Orange.

So it is entirely possible that the fan comes on and the compressors do not.

There are a couple of things you might do before swapping the tstats. After removing the tstat to look at the back, I would check to see if a previous owner jumpered the W Aquahot to the GL OR GH intentionally. I don’t think that is the case but who knows what may have been done.

The second thing is take the voltmeter and run the tstat through its paces. It should put out 12V at the terminals.

With heat on, check the GL and GH terminals for 12V. It should not be present.

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