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topdownman · 11-13-2017, 11:03 AM

I have questions about my heat pump(s). We just returned from camping where the weather was quite cold (20-30s). We have a new to us 2011 Phaeton 40QTF. It has the 10K generator and three rooftop air units with one thermostat (zone 1, 2 and 3). I have found that only zone 3 offers an electric heat option (in the bedroom) for the heat pump and it works fine. The other two units do not. I pulled my literature and have found that all three units are identical. Coleman Airxcel 49024A879. On the thermostat, neither zone 1 or 2 have an electric function while on heat, only gas. It appears that zone 1 controls the front gas furnace and zone 3 controls the bedroom gas furnace. Zone 2 appears to have no function on heat although it does show a gas option. I was told somewhere there are dip switches on the AC unit that need to be set so that the thermostat knows there is a heat pump up there. I've done some searching but can find nothing on the interweb. Does anyone have any insight? This is cross-posted so sorry for the duplication.

imUrlaub · 11-17-2017, 04:10 PM

If your original documentation shows all three units are identical then there might be a communication issue between the controllers and the units. Many manufacturers build identical AC units some with and some without heat pumps. So, while you could have identical AC units they may not all have the heat pump option. If you don't have the original Tiffin documents then contact Red Bay and ask them. Their customer service is legendary.
Be aware that heat pumps really don't work all that well in freezing temperatures. The reason is that they are still AC units but in reverse. So all that exhausted cold air can cause the unit to freeze up. When that happens an electrical coil is energized. It doesn't give you any heat just unfreezes the unit. But, when it is cold the unit re-freezes in short order.

topdownman · 11-25-2017, 08:20 AM

Quote:

Originally Posted by imUrlaub

If your original documentation shows all three units are identical then there might be a communication issue between the controllers and the units. Many manufacturers build identical AC units some with and some without heat pumps. So, while you could have identical AC units they may not all have the heat pump option. If you don't have the original Tiffin documents then contact Red Bay and ask them. Their customer service is legendary.
Be aware that heat pumps really don't work all that well in freezing temperatures. The reason is that they are still AC units but in reverse. So all that exhausted cold air can cause the unit to freeze up. When that happens an electrical coil is energized. It doesn't give you any heat just unfreezes the unit. But, when it is cold the unit re-freezes in short order.

This is resolved. The thermostat was incorrectly programmed. Once I reprogrammed the thermostat all 3 heat pumps work correctly.