ccmtcanada Posted September 2, 2011 Report Share Posted September 2, 2011 Ok...I decided to get a programmable thermostat...all the other ones I've wired in the past were easy...just match the exact wire colours to the corresponding lead. My existing thermostat has a 5 wire system... The new one has only 4 leads... The instructions to install says "If you have 2 R wires (which I do...RH for heat and RC for air cond), then connect each wire to its corresponding terminal and remove the jumper" between the RH and RC terminals". So, here's where I'm confused.... 1) I do not see "corresponding terminals" on the new 4 lead thermostat. 2) The jumpers (see pic below) are not labelled RH and RC...they read RE and HG, which from the instructions say it's for electric or gas systems. The instructions also say "depending on your system, you may need to connect 2 to 9 to the thermostat", but then do not tell you how to do that.... Any help would be appreciated! Thanks! Link to comment Share on other sites More sharing options...
fishnsled Posted September 2, 2011 Report Share Posted September 2, 2011 The new one has only 4 leads... I think the problem is that the unit is upside down. Look at the label. Flop it around and you will be fine. I don't have a clue but thought I'd bump it up for you. Link to comment Share on other sites More sharing options...
GBW Posted September 2, 2011 Report Share Posted September 2, 2011 Ah Cliff, this is easy...even I can do it. ready? Go back to the store and get a 5 wire system. Problem solved... Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 2, 2011 Author Report Share Posted September 2, 2011 Will and Geoff...thanks a lot!!! Since you couldn't help with that, you can come over and help me move a recliner sofa from my basement to the main floor instead!!! Lol Link to comment Share on other sites More sharing options...
GBW Posted September 2, 2011 Report Share Posted September 2, 2011 sorry, I didn't hear that, your phone is cutting out.... Link to comment Share on other sites More sharing options...
fishnsled Posted September 2, 2011 Report Share Posted September 2, 2011 sorry, I didn't hear that, your phone is cutting out.... I'm having the same problem Geoff. Maybe his phone line is crossed with the thermostat..... When were you looking to do this Cliff ( the recliner sofa)? Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 2, 2011 Author Report Share Posted September 2, 2011 I'm having the same problem Geoff. Maybe his phone line is crossed with the thermostat..... When were you looking to do this Cliff ( the recliner sofa)? Whenever you get here...beer and pizza as payment??? Lol Link to comment Share on other sites More sharing options...
aplumma Posted September 2, 2011 Report Share Posted September 2, 2011 send a P.M. to Dan C or Daplumma they might have the answer.Cliff Art Link to comment Share on other sites More sharing options...
Terry Posted September 2, 2011 Report Share Posted September 2, 2011 what model of stat is it I think when they are referring to 2 wire, they are talking about a common 2 wire system that will run a gas or oil furnace thermostat but out of context it's hard to say Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 2, 2011 Author Report Share Posted September 2, 2011 Terry...its a Garrison brand, model THM321. I'm leaning towards the two R wires are a common hot wire, so thinking of joining them together. An electrician friend believes on my older unit they are likely combined inside anyways. Will research a bit more before trying anything. Thanks everyone! Link to comment Share on other sites More sharing options...
Pikeslayer Posted September 2, 2011 Report Share Posted September 2, 2011 Cliff, Forget the damn thermostat. Check your pm. Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 2, 2011 Author Report Share Posted September 2, 2011 Lol Simon...PM answered! Link to comment Share on other sites More sharing options...
dannyboy Posted September 2, 2011 Report Share Posted September 2, 2011 You may need a 5-wire thermostat: RH(heat)and RC(cooling)are wired separately for power if you have a two-transformer system, the separate 24v transformers supply power to switch cooling and heating. In some cases they are jumpered if you have only a single transformer. W is your heating terminal, and normally will have a white wire. G is your fan terminal, and will normally have a green wire. Y is your cooling terminal normally this wire would be yellow. If you're not sure call a pro. Good luck. Dan Link to comment Share on other sites More sharing options...
Terry Posted September 2, 2011 Report Share Posted September 2, 2011 would your units be self switching when you are calling for heat or cooling, power will be sent to both.... would they fight each other.... not sure Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 2, 2011 Author Report Share Posted September 2, 2011 (edited) Figured the white (heat) and yellow (cool) would complete the correct circuit and engage either the furnace or A/C. I will head downstairs and check if there is one or two transformers...if only one, I will bridge them together I think. Both A/C and furnace were installed together new, so hoping all on one transformer. Edited September 2, 2011 by ccmt Link to comment Share on other sites More sharing options...
JeffBornFishin Posted September 3, 2011 Report Share Posted September 3, 2011 Figured the white (heat) and yellow (cool) would complete the correct circuit and engage either the furnace or A/C. I will head downstairs and check if there is one or two transformers...if only one, I will bridge them together I think. Both A/C and furnace were installed together new, so hoping all on one transformer. PM sent... Please don't let out the magic smoke Cliff Link to comment Share on other sites More sharing options...
Daplumma Posted September 3, 2011 Report Share Posted September 3, 2011 How old is the house/unit.Most of the new stuff 1985 on up should be single tranformer stuff.If its a two trans system you will have to lose the rc trans and rewire for a 4 wire stat.Its not hard but I first need to know if its a one or two trans system. Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 3, 2011 Author Report Share Posted September 3, 2011 How old is the house/unit.Most of the new stuff 1985 on up should be single tranformer stuff.If its a two trans system you will have to lose the rc trans and rewire for a 4 wire stat.Its not hard but I first need to know if its a one or two trans system. Thanks for checking in here! The AC and furnace were installed brand new as a package 10 years ago...so that would be 2001. I followed the wiring in from the AC inside and it goes inside the furnace, so I'm assuming it would be a one transformer setup.... Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 3, 2011 Author Report Share Posted September 3, 2011 (edited) PM sent... Please don't let out the magic smoke Cliff Thanks for the PM...I've sent one back! Let out the magic smoke? I'm confused!! LOL Edited September 3, 2011 by ccmt Link to comment Share on other sites More sharing options...
Daplumma Posted September 3, 2011 Report Share Posted September 3, 2011 Thanks for checking in here! The AC and furnace were installed brand new as a package 10 years ago...so that would be 2001. I followed the wiring in from the AC inside and it goes inside the furnace, so I'm assuming it would be a one transformer setup.... I wondering why they would have a RC from to the stat then unless they jumpered it in the furnace.There should be a circuit board in the furnace.Take a pic of the lowvoltage(t stat wires) and I may be able to muddle thru it.Its not a lennox is it? Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 3, 2011 Author Report Share Posted September 3, 2011 I wondering why they would have a RC from to the stat then unless they jumpered it in the furnace.There should be a circuit board in the furnace.Take a pic of the lowvoltage(t stat wires) and I may be able to muddle thru it.Its not a lennox is it? Nope, it's not a lennox...thanks for your help! Here are a few pics...first is the entire board... This is a close up of the corresponding wiring that runs upstairs... Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 3, 2011 Author Report Share Posted September 3, 2011 If I had looked at the circuit board in the first place I could have answered my own question!! I see the RC and RH wires are on the same terminal on the board...so I will just join those same two at the thermostat and attach it to the R terminal. Thanks everyone for the PM's and assistance in this thread...much appreciated! Link to comment Share on other sites More sharing options...
GBW Posted September 3, 2011 Report Share Posted September 3, 2011 so, did you go buy the 5 wire unit then? Link to comment Share on other sites More sharing options...
ccmtcanada Posted September 3, 2011 Author Report Share Posted September 3, 2011 Lol Geoff! Nope, got some great advice and feel confident now that I heard from a licensed HVAC tech from the board! Btw...the phone works just fine, will call you when I need that recliner moved lol Link to comment Share on other sites More sharing options...
GBW Posted September 3, 2011 Report Share Posted September 3, 2011 Lol Geoff! Nope, got some great advice and feel confident now that I heard from a licensed HVAC tech from the board! Btw...the phone ____ just fine, will c___ you when I ___ that __liner ____ lol ah all's well that ends well eh Cliff? I was going to tell you to hook the two up all along but I wasn't home to look at mine to confirm... Oh and even your post has a problem there so I didn't get it all hence the quote. I'll swing buy on the ___ in you ____, sound ___ if not then let __ ____ or you ___ on your own... Link to comment Share on other sites More sharing options...
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