View Full Version : Wiring new thermostat
jedalton
Jan 23, 2013, 09:40 AM
How do I wire a 1f78 White Rodgers programmable thermostat to a Ruud heat pump model RQNL-B036JK. I have 5 wires coming out of wall as follows; red, white, green, yellow and orange. On the 1f78 I have 2 wiring blocks, on the top one it shows W, RH, B & RC with the RH & RC with a jumper wire. On the bottom it shows; G, O, & Y.
Any help is greatly appreciated.
drtom4444
Jan 24, 2013, 10:07 AM
There should be a sheet with the thermostat telling you how to wire it. As long as you have a meter you should have no problems. RH and RC are tied together unless you have two transformers for control voltage (24 volts). The "O" to orange which is the reversing valve, G to Green or fan relay, W1 or 2 to white,or the heat strip relay, Y is yellow or the main contactor in outside unit, R is Red or other side of transformer from Common, C is common which is one side of 24 volt transformer. Simple, but use a meter.
Here are some diagrams: https://dl.dropbox.com/u/8010163/AC%20Wiring%20Diagrams.zip
jedalton
Jan 24, 2013, 05:52 PM
There should be a sheet with the thermostat telling you how to wire it. As long as you have a meter you should have no problems. RH and RC are tied together unless you have two transformers for control voltage (24 volts). The "O" to orange which is the reversing valve, G to Green or fan relay, W1 or 2 to white,or the heat strip relay, Y is yellow or the main contactor in outside unit, R is Red or other side of transformer from Common, C is common which is one side of 24 volt transformer. Simple, but use a meter.
Here are some diagrams: https://dl.dropbox.com/u/8010163/AC%20Wiring%20Diagrams.zip
OMG that was awesome information. Thanks so much for taking the time to answer my question with so much detail. I decided to have the HVAC tech come over tomorrow and wire it up just to be on the safe side. I'll keep you updated.
ballengerb1
Jan 24, 2013, 06:22 PM
The color of the wires coming out of your wall is not always 100% safe to rely on. Check the wires in your furnace at the mother board. Wires are terminals are all color coded but there is never a 100% guarantee the original installer follow the rules. The rest of what drtom says looks correct but confirm at the mother board. Page 2 of this maual should help you a great deal. Removing Old Thermostat - White Rodgers 1F78 User Manual [Page 2] (http://www.manualslib.com/manual/194488/White-Rodgers-1f78.html?page=2#manual)
jedalton
Jan 24, 2013, 08:02 PM
The color of the wires coming out of your wall is not always 100% safe to rely on. Check the wires in your furnace at the mother board. Wires are terminals are all color coded but there is never a 100% guarantee the original installer follow the rules. The rest of what drtom says looks correct but confirm at the mother board. Page 2 of this maual should help you a great deal. Removing Old Thermostat - White Rodgers 1F78 User Manual [Page 2] (http://www.manualslib.com/manual/194488/White-Rodgers-1f78.html?page=2#manual)
Thanks
drtom4444
Jan 25, 2013, 08:36 AM
That's a good point about color codes which is why you check how it is wired and what color wires go to the different terminals. Some units do not have a terminal board. On those they tie the wires together going to outside unit and G,R,C, and W1 or W2 ties to furnace. Then O, C, and Y go to the outside unit, but some units also have a G and an X for special uses, sometimes.