Thermostat conecting 3 wires

jacobo 348 · 08-15-2009, 02:16 PM

I want to change my mercury thermostat to a digital White Rodger 1F86-344.
I have only 3 wires R,Y,G,. the digital thermostat diagram for 3 wire cool only system tell me:
to jumper RH and RC terminals shold connect to my R wire,
Y terminal connect to my Y cable
and G terminal connect to my G wire.
Then it tells me to connect de C terminal?? I do not have this cable and I do not thing I should jump G and Y to C., i am afraid to short the AC sysstem what should I do? here is the link to the diagrams
http://www.white-rodgers.com/wrdhom/..._06_pg0178.pdf

Thanks

**Basementgeek** · 08-16-2009, 07:28 AM

Hi and welcome to TSF

Don't jumper G & Y to C.

It could help if you could find a wiring diagram for the old thermostat and post it.

BG

jacobo 348 · 08-17-2009, 07:42 AM

I do not have the wiring diagram for the old thermostat. It is an mercury mechanic thermostat and it was conected R,Y,G,.
Thanks again

**speedster123** · 08-31-2009, 05:56 AM

Old thread but-
Call White Rodgers
The C terminal is the neutral/ground coming from the 24 volt transformer.
Do not jump any other wire to it.
You might leave that alone, but call.

08-15-2009, 02:16 PM	#1 (permalink)
jacobo 348 Registered User Join Date: Aug 2009 Posts: 2 OS: xp	Thermostat conecting 3 wires I want to change my mercury thermostat to a digital White Rodger 1F86-344. I have only 3 wires R,Y,G,. the digital thermostat diagram for 3 wire cool only system tell me: to jumper RH and RC terminals shold connect to my R wire, Y terminal connect to my Y cable and G terminal connect to my G wire. Then it tells me to connect de C terminal?? I do not have this cable and I do not thing I should jump G and Y to C., i am afraid to short the AC sysstem what should I do? here is the link to the diagrams http://www.white-rodgers.com/wrdhom/..._06_pg0178.pdf Thanks

08-16-2009, 07:28 AM	#2 (permalink)
Basementgeek Moderator, Home Support Join Date: Feb 2005 Location: Central Ohio, USA Posts: 1,461 OS: XP Pro SP2/Vista Ultimate SP2 Blog Entries: 3	Re: Thermostat conecting 3 wires Hi and welcome to TSF Don't jumper G & Y to C. It could help if you could find a wiring diagram for the old thermostat and post it. BG __________________ Donating to the forum keeps TSF free for all. Proud member of ASAP

08-17-2009, 07:42 AM	#3 (permalink)
jacobo 348 Registered User Join Date: Aug 2009 Posts: 2 OS: xp	Re: Thermostat conecting 3 wires I do not have the wiring diagram for the old thermostat. It is an mercury mechanic thermostat and it was conected R,Y,G,. Thanks again

08-31-2009, 05:56 AM	#4 (permalink)
speedster123 Mentor Join Date: Oct 2006 Location: United States-New York-Long Island Posts: 5,194 OS: xp pro SP3 My System	Re: Thermostat conecting 3 wires Old thread but- Call White Rodgers The C terminal is the neutral/ground coming from the 24 volt transformer. Do not jump any other wire to it. You might leave that alone, but call. __________________