Separate Furnace Thermostat

[RickT]

I have a 01 Windsor 38 PBDD with a 5 button Duotherm Furnace / A/C thermostat. When I set the heat pump temp to say 70* it changes the furnace temp to 70* also(or visa vera), so 1 or the other or both come on. I read on a forum somewhere that the furnace is controlled by 2 wires, that when connected tegether turn on the furnace. I would like to install a 2nd thermostat just for the furnace so I can use the heat pumps without running the furnace or furnace without the heat pumps. I would set it at a lower temp so it comes on if it gets too cold. I hate having to scroll through all the zones and modes to set the Furance. Has anyone done this, or know which 2 wires are used to turn on the furnace? I think a digital setback thermostat could do this.

Thanks, Rick

[Shadowcatche]

Not knowing what model you have and looking for something generic I found the manual for the 6600
http://bryantrv.com/docs2/docs/operating/dt6600.pdf
Yes it is in this case two wire and yes you could add an additional thermostat. Just remember that the furnace will take its cue from which eve thermostat is set higher.

[Mike Canter]

That thermostat configuration is controlled by DIP switches located in the AC unit on a printed circuit board. It sounds to me like the correct switches are not set to program the thermostat that you have a heat pump as well as a furnace. Do you any manuals on your AC unit that shows the DIP switch configurations. Once you set these DIP switches in the correct configuration you have to do a rest on the thermostat so it will read the DIP switch setup. You do that by turning off the power switch on the bottom of the thermostat and while pressing and holding both the MODE and ZONE switch in you turn the power back on and release the buttons. It maybe that is all you have to do now.

On my MH the heat pumps come on when HEAT is selected and the furnace comes on when FURNACE is selected. They never both come on at the same time.

[Diplomat Don]

RickT....As Mike said above, something is not set up correctly. The heat pumps will only provide heat down to about 35 -40 degrees (outside temp). Once they reach their limit, the heat pumps shut down and the furnace takes over. They shouldn't run together.

[RickT]

Thanks for the help guys,
I have 2 Dometic 630515 A/C's and a Suburban 425F Furnace. What I may be doing is leaving the thermostat in Furance mode when what I wanted was for the heat pumps to run. Just trying to save propane ya know. I thought all zones and modes are active for the temps that are set. As for both A/C's to run if you want them to. I wish you could turn off what you don't want on. I will check the dip switches.

Rick

[Mike Canter]

Rick, can you selected HEAT mode on all your thermostats and zones? And can you also select FURNACE mode on all your thermostats and zones?

If you don't have the manual for your AC units then go to page 15 of the following and it has the DIP switch settings
http://www.dometic.com/b3056cd0-1a5b...2d4ac84d.fodoc

If you have two roof AC units and two separate thermostats then I believe that all DIP switches should be off except for #5 for a furnace. If you have three roof AC units and two thermostats then you have to set a zone on the DIP switches for usually the back thermostat.

Para #2 on Page 15 covers the rest of the thermostat.

[RickT]

I can select HEAT mode on both zone 1 & 2. FURNACE mode on zone 1 only.

[Mike Canter]

How many furnaces do you have? How many wall thermostats do you have?

[RickT]

1 furnace and 1 thermostat, 2 a/c (heat pumps)

[Mike Canter]

Then for the winter if you want just the furnace on then Zone 1 MODE would be set on FURNACE and Zone 2 MODE would be OFF. If you do not turn Zone 2 MODE OFF and have it in HEAT then the one AC unit will be in heat pump mode and running.

If you want heat pumps and no furnace then both Zone 1 & 2 MODE will be HEAT

If it is done that way then you should never have the furnace and a heat pump on at the same time.

Heat pumps do not work well when it is in the 30's or below. I run my heat pumps if it is chilly and 40's or above. In the 30's or below I run just my furnace.

[RickT]

Thanks again Mike,

I will try that. I think I was leaving the control on furance and thats why it was coming on. I haven't seen where I can turn a mode off.

Rick

[Mike Canter]

If you select a Zone and then keep pushing the MODE button it will cycle through all the different modes and then come to a position where all the mode display goes blank. That is OFF for that Zone. It is hard when they use ONE thermostat for two Zones because you have to always remember that other Zone is there and running unless you select OFF.