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Wiring Multiple Thermostats

IVB

Senior Member
Has anyone here installed multiple thermostats?

I'm contemplating getting a 2nd 8870 to put in my kids bedroom. That way, I *think* I can turn off the main one and turn on that one at nighttime, and let their bedroom control the furnace. The house is forced air heat, single-zone.

If that works out, which I think it should, i'd get the aprilaire 8818 distro panel to wire both 8870's to, then put the protocol adapter against that and run into CQC.

anyone think this will work? Won't work? Again, the entire goal is to find a way to have the temp in the kids bedroom control the furnace at night.
 

hucker

Active Member
Please keep us posted on your progress on this front. I too would like to have two thermostats on one furnces. I could use my automation hardware to 'switch' between the two. I'm looking at RCS hardware though...

I'm several months out though so I can learn from you :lol:
 

electron

Administrator
Staff member
I want to do the same thing with my master bedroom, so I just bought an Elk temp sensor instead of a 2nd thermostat. Still have to hook it up tho, but it should work.
 

Jim Doolittle

Active Member
I want to do the reverse and use a couple RCS X10 thermostats to control 6 zone heating. Three zones would be controlled by one stat and three zones with another stat. To not totally lose zone control, I want to have one-wire temp sensors control whether a given zone valve is open or not.

This solution would be perfect since I already use the two stats (one in upstairs hallway and one in downstairs hallway) for two AC units.

Anybody have any expertise on how I would wire this?
 

IVB

Senior Member
electron said:
I want to do the same thing with my master bedroom, so I just bought an Elk temp sensor instead of a 2nd thermostat. Still have to hook it up tho, but it should work.
I actually have an Elk temp sensor, but what I can't figure out is how to accurately set the Heat Set Point on the thermo without constant micro-adjustments.

In my case, the airflow between the two rooms is completely different. Hence, if I say that the current KBR temp is 65deg and I want it to be 72deg, I can't just add 7 to the HeatSetPoint, cuz it'll bake the KBR.

If I turn the heat on until the KBR reaches 72, then have a 2nd trigger to reset the HeatSetPont to whatever the current reading is, then the temp will either plummet in the KBR (hence triggering another heat set event), or the temp will plummet in the room with the thermo resulting in a mega-bake of the KBR.

Hence, given my airflow issues, I suppose I could muck with the triggers until I get them right, or spend the extra $180 ($230 for the 8870, $50 for the temp sensor) and not deal with it. Given the cost of being wrong is my kids either freezing or baking, either of which result in them waking up and waking me up, I'll spend the extra $$ ;)
 

electron

Administrator
Staff member
I have the same airflow issues, but I am really counting on that temp sensor (assuming I can get my thermostat issues figured out).

I was first considering using a second thermostat as well. I was just going to use 2 cheap ones, and have the power to the thermostats be controlled by Elk M1 (so there is always 1 on).
 
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