Need help connecting my HAI RC80 thermostat

electron

Administrator
Staff member
I had to replace my thermostat with a new one, so I decided to install the HAI RC80 I ordered a while ago. Everything works, except for the AC. I can turn the fan on manually, can control heat just fine, but when setting it to cool, or cool auto, nothing happens. See the pic below for the old wiring configuration.



In that picture, 4 wires go to the thermostat:

white -> W
red -> RH/RC
green -> G
blue -> Y

So I hooked up those wires to the matching terminals on the RC80 (only the C terminal is not used), but I guess the problem is maybe with the RH/RC jumper config on the old thermostat? Any help would be greatly appreciated. Thanks!
 

carry15+1

Active Member
The separate RH and RC terminals on your old stat allow for separate transformers for the furnace and compressor - if they were jumpered you only have a single transformer, and your connections to the RC80 should work.

You are aware that there will be maybe a 3 minute delay before the AC will start right? This is to prevent short cycling the compressor.

The 240v circuit breaker for the compressor is on right?
 

electron

Administrator
Staff member
I think I waited between 3-5 minutes before turning it off, but I guess I will have to try again,especially since you say there is supposed to be a delay, and wiring looks ok. Breakers looks fine too. Thanks!
 

carry15+1

Active Member
The minimum on AND off times for AC are programmable in the RC80B - see option 11 in installation manual.

Just for grins you might check all the installer options - perhaps something in there is causing you a problem.

To confirm that your wiring is okay you could remove the blue (Y) wire and jumper it to RH/RC - the compressor should run (go outside and check it). Don't do this for an extended time as the furnace fan will not be on to move air across your coil.
 

Mike

Senior Member
electron said:
I had to replace my thermostat with a new one, so I decided to install the HAI RC80 I ordered a while ago. Everything works, except for the AC. I can turn the fan on manually, can control heat just fine, but when setting it to cool, or cool auto, nothing happens. See the pic below for the old wiring configuration.



In that picture, 4 wires go to the thermostat:

white -> W
red -> RH/RC
green -> G
blue -> Y

So I hooked up those wires to the matching terminals on the RC80 (only the C terminal is not used), but I guess the problem is maybe with the RH/RC jumper config on the old thermostat? Any help would be greatly appreciated. Thanks!
There is a code in the manual to avoid the delay (it may be 1-3 minutes when it first turns on that it won't trigger anything). I am not home now, but you may want to check the manuals for this. I know it helped me a lot when testing.

I needed to have a relay run on the common (and it is 24v so that could be problematic). I had someone help me and a relay was used (I don't remember the details though). Seems like your heat is working though, so I don't think it is this.

That does not look like the one I have though (mine is the one with the backlight (RC80B I think).

I have one being put in in the next week or two for cooling (same issue with the common so I have an electrician fixing that while working on some other items). I can let you know how that goes, I just don't remember when he was coming in to do the work.
 

electron

Administrator
Staff member
That's my old thermostat. Thanks for the info guys, I am going to have to find that install manual again, and find out where this delay is set. I am hoping i don't have to screw around with relays.
 
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