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Hydro hot fan comes on when I turn on the roof H/A

Yahoo Message Number: 63434
When I turn on the roof heater (thermostat set on elec heat) in zone one my front hydro hot heater fan comes on putting out cold air.

Any idea how that can happen?

Frank 06 Allure 31425

Re: Hydro hot fan comes on when I turn on the roof H/A

Reply #1 –
Yahoo Message Number: 63436
Couple of possible answers. If the thermostat thinks the temperature is below the capability of the roof heat pump it will default to gas heat. If the diesel is off you will get cold air.

Here is the quote from my thermostat book:

Heat Pump Lockout

"If the system has both gas heat, (LP furnace or hydronic heat) and electric heat,(electric strip heat or heatpump) appliances installed in the same zone, then the system will automatically switch from Heat Electric to Gas Heat if the electric heat can not satisfy the desired setpoint temperature. Because of the nature of the electric heating systems, they tend to be less effective the lower the outside emperature. Therefore, at low temperatures, your electric strip heat or heatpump may not be able to satisfy the setpoint. The system switches from Heat Elec to Gas Heat when the actual zone room temperature is five degrees or more below the desired setpoint temperature. If this happens three times in a row, the electric heat is locked out for two hours and the gas heat is the primary heat source. When this happens, the LCD will continue to display Elec but the word Gas will flash on the LCD to alert the user that the electric heat source is locked out. See table below for an example of how the heatpump lockout system works."

If that is not the case then the thermostat is having a senior moment and you might try turning the house DC off, waiting a couple of minutes, and turning the DC back on. That might reset the thermostat.

Bob

'05 Intrigue 11872

Re: Hydro hot fan comes on when I turn on the roof H/A

Reply #2 –
Yahoo Message Number: 63439
Frank:

Did it ever work proberly? In my 06 Allure the rear fan would come on when I had it set for Hydro-Hot. The problem was the factory and not wired the thermostat correctly. Moving 1 wire corrected the problem.

Steve

06 Allure 31299

Re: Hydro hot fan comes on when I turn on the roof H/A

Reply #3 –
Yahoo Message Number: 63447
Not sure, we use the heater rarely, never used the hydro for heat.

Frank Allure 31425

Re: Hydro hot fan comes on when I turn on the roof H/A

Reply #4 –
Yahoo Message Number: 63449
Bob

You hit it on the head. I was turning the stat up a bunch first thing in the morning to take the chill off. By turning it up more that 5 degrees above the room temp it kicked on the hydro hot. Juut tried it and thats what happened.

Thanks for the help.

Frank Allure 31425