# Facts about thermostats



## mdshunk (Dec 4, 2005)

I can't count the number of times I've been on a service call, and the customer is sure that the thermostat is bad. People are quick to blame the piece of the system that they are famaliar with. While thermostats do fail from time to time, about 99% of the time that a customer thinks that a stat is bad, they are just plain wrong. I'm happy to install a new one if they insist, but it's often unnecessary. Consequently, set back thermostats might not save you any money, but that's almost another thread.


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## #CARRIERMAN (Oct 18, 2006)

Hi DIY,ers

Was hoping to see more visits on this topic, and even hoped for a few questions for mdshunk and myself. Hopefully the ones of you that visited got some insight, thats all that really matters.

I was going over some things with my techs, just thought I would add it in with this post. You will run into older thermostats, some of them used this nomenclature.

Old / New
V= R (24 volts hot)
4= RH (24 volts hot)
M= Y (24 volts outut Cool)
R= O (24 volts output Reversing valve)
F= G (24 volts output Blower)
Y= W2 (24 volt output Heat, heat pump only)
H= W (24 volts output Heat)
X= C (24 volts common or neutral) same rules apply as in previous post. Just a little more information, as before if you don't find it in a post. Please don't be afraid to ask.

Carrierman


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## #CARRIERMAN (Oct 18, 2006)

Hi DIYers

I have been reading some post about thermostat changeouts gone wrong. Thought I would go back in the archive and drag this one back out. If there are any questions after reading this, please let us know and one of us will be glad to help you with it.

Carrierman


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## diywoman (Jan 4, 2007)

*Noma Thermostat vs Old Thermostat*

I have a Noma Programmable Thermostat with places for 4 wires to be connected. The Problem? I have "5" wires coming from the furnace that were all connected to the old thermostat. I was told I could wrap the #4 wire and not use, but that resulted in no-heat.







So obviously this wire needs to be connected, but I don't know to where or with what. I have a picture of the old set-up showing the wires labeled etc. 
All below except the #4 have the proper place in the new thermo...but this black wire must either connect with one of the others or be used in place of. The instructions discuss this but do not cover the wire I'm dealing with. (likely only because its perhaps not called "4" now) 
G-Green
RC-Red
W-White
Y-Orange
4-Black

Any help would be most appreciated.Thanks in advanced!

DIYW

http://ca.pg.photos.yahoo.com/ph/lisabongard/detail?.dir=/1d6cscd&.dnm=a91fscd.jpg&.src=ph

**These are the days I miss my Dad the most...Wisdom..such Wisdom**


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

The #4 terminal on the old thermostats were what is now the RH terminal. This probably means that you have an older system with two transformers. If this is so you will need to get a thermostat with seperate RC and RH terminals. That would be the easiest fix, not sure if they are available to you. White Rodgers 80 series stats are amongst the most reliable and best priced on the market.

Good luck
Rusty


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## diywoman (Jan 4, 2007)

Thank you very much for your advice. I am in Canada, and am unsure of that brand name. It's not a known brand here. I even checked with some of our American hardware stores and they don't carry that, but I am sure I will be able to find the right thermo...
I do appreciate this site and the helpful info available. I would normally leave electrical jobs to the PRO's, but this seemed like a DIY'er, which it is, providing you get the right start.

AGAIN Thanks, Rusty!!

Lisa


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

Just wanted to say, if you need us anymore you now where to come too. I am not the only one here, there is a lot of good talent on this sight. Anyone of them will help be willing to help you if they can.

Good luck
Rusty


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## trollmastergeneral (Dec 19, 2006)

Can you tell us what colors are hooked up at the furnace and to what letters on the board:yes: I think we could get you there.:whistling2:


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## #CARRIERMAN (Oct 18, 2006)

Hi trollmastergeneral

If you give us the wire colors available to you and the designations on the stat and board. If I can't figure it out, I'm calling on you and mdshunk to bail me out.

Rusty


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## trollmastergeneral (Dec 19, 2006)

If she gives us all that I will look like the hero lol:whistling2:


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## diywoman (Jan 4, 2007)

Thanks guys...Seems like all the gentlmen are in the USA...
It's a Grimbsy (I believe) 

From the wall i have the following wires
G-Green
RC-Red
W-White
Y-Orange
4-Black

The Thermostat has locations for the "G,RC,W and Y"

I dont have a known place to hook up the #4(which Rusty tells me is equivalent to an RH)


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

If you have a Grainger supply in your area you will be able to find a thermostat that will work for your application. I am not sure if your system has two transformers for certain, but there is a good possibility it does. This is why you need the thermostat with the seperate RC and RH terminals.

Good luck
Rusty


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## diywoman (Jan 4, 2007)

browsing through the flyers last night I found the local Home Hardware has a Rodger White on sale...so they may have the one I'm looking for. I'll pop over at lunch and see. Unfortunately I now have a perfectly good thermo and no receipt to take it back...maybe if I batt my lashes and look real cute they'll take it back,......HA HA NOT! 

Thanks.


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

You never know, if you get one of the younger guys. You might be able to pull it off. Besides, I have seen some of you Canadian ladies, some of you are drop dead gorgious.

Good luck
Rusty


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## diywoman (Jan 4, 2007)

:blush: I'm at the age now where the young ones are not sure what to think...I'm a momma at 31 (orginal post said OF 31...YIKES!!), but still not old enough to be their momma yet!! ha ha. Besides which, Canadian men just don't hold a candle to some American men...the whole grass is greener...ya know the deal....:icon_rolleyes:


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

Just wanted to check in and make sure you were able to get your thermostat ok. Let us know if you need any further help.

Rusty


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## diywoman (Jan 4, 2007)

well the bonehead :thumbsup: at the local hardware store was not interested in a sale. He wouldn't even try to help me find out which one was the one I needed.(White-Ridger's were on sale) They are packaged up so tightly now-days that you have to cut them open, so you can't peek in the packages and there was no diagram on the back. I'm just going to go into the place I know I can get one(NOMA)..I Just kinda wanted to wait for them to go on sale..the one I need is twice the price. I'll be sure to let you know how I made out. They are easy to install, just need the right one is all!! :wink: 

Lisa


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

We will be waiting to hear of your success. Good luck, if you still need us, you know where to look.

Rusty


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## trollmastergeneral (Dec 19, 2006)

I wonder if your problem may be because the rh and rc were not jumpered.


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## diywoman (Jan 4, 2007)

explain the word jumpered :huh:and I might be able to expand on that comment. 

Please!

Re-reading the first posts. I missed the one that answered my question...sorry for being so blind. (you stated early that 4=RH)
With that in mind, being as R and RH are both 24 volt Hot, can they not be conncected together?:confused1:

Lisa


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

On thermostats that come with seperate RC and RH terminals there is a jumper wire to go between them. The one thing that worried me is the fact that your old thermostat had wires on RC and 4. This generally means that the system has two transformers. There will be one in the A/C condensing unit and one in the furnace. If this is so and you put them together this is a direct short and will burn one of the transformers if not both of them up. Thats why I suggested the thermostat with the seperate terminals to keep this from happening. Hope this help to clear this up, if not let us know.

This is where the two transformer problems come in. But the simple answer is no. If you can verify that the system has only one transformer, than RC and RH should be tied together. I cannot verify that for you without seeing the physical equipment. Thats why I wanted you to play it safe, dont want you to get discouraged or give up.

Good luck
Rusty


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## diywoman (Jan 4, 2007)

OK. I was not fond of the idea of putting ANY two wires together anyhow, so I'm good with getting the accommodating thermo. 

Well the good news is that the thermo I need is half price starting today...YIPPIE!! **sad how excited I am over a thermostat**
And Someone offered to buy the one I already had. COOL!!
One thing has led to another. I checked out the furnace and my filters need changing, so I picked those up this morning. 

ANyone ever seen the Canadian show on HGTV called *Holmes on Homes! *I love this guy...I can't believe the crap people try to build these days. Cutting out floor joists to make room for duct work...hacking on the main beam cause its 'in the way" OH MY. I feel sorry for those who don't know the least little common sense about a home. They get scammed!! One show they had over 20 junction boxes in ONE room, AND they were all covered up. Only found when they pulled everything down. If I don't know something, I'm not gonna just jump in. I do my homework. Even when I'm going to get someone else to come do it. I just feel better about it that way.

thanks guys, I'll post my results when I get it all hooked up. 

!!Next Project is the bathroom....Lord have Mercy!!!


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

Thats good news, as far as the remodel we would love to see your progress on that also. I know the guys that helped you will track your progress on the other forums and even add their opinion when you ask.

Good luck
Rusty


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## diywoman (Jan 4, 2007)

*Update!!*

Thermo is installed and working wonderfully!! I had to remove the jumper on the new thermo and connect both the RH and the RC to their appropriate places. Now for the real test...Waiting to see what my next hydro bill comes in at. See if what they say is true...I'm expecting some money back into my pockets, for all the trouble I went through to install it. 

One thing through all this, is you become much more educated by the end.

Thanks to everyone who put in their helpful suggestions.:thumbsup: 

This is an awesome site. 

Lisa


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## #CARRIERMAN (Oct 18, 2006)

Hi diywoman

If you don't mind, when you get your bills and start comparing them. Let the people know about what your savings are so they can make an educated choice. 

Thank You.
Rusty


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## diywoman (Jan 4, 2007)

*$aving$*

I will be sure to do that. I will have two comparisons. One the amount of oil consumed...and the other hydro to run it all.
This may be hard to calculate as we have had fairly mild weather up until now. Monday we got a HUGE cold snap (-20 c) so who knows.


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## #CARRIERMAN (Oct 18, 2006)

Thanks again diywoman, we are looking forward to your insight and your next project.

Good luck
Rusty


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## #CARRIERMAN (Oct 18, 2006)

Just wanted to keep this one easy to get to.

Rusty


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## #CARRIERMAN (Oct 18, 2006)

Hi DIY'ers

I am seeing thermostat problems again, I am dragging this one back out of the archive.

Carrierman


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## #CARRIERMAN (Oct 18, 2006)

Hi again DIY'ers

I am seeing thermostat questions again so I am dragging this one out of the archive again. And as always if you have any questions, let us know.

Good luck
Carrierman


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## surferntx (Feb 24, 2007)

*Possible thermostat issue...*

Hey everyone, looks like I may have found the right place for some help. Last night when we came in, we noticed the air hadnt been on. I turned it on at the thermostat, nothing. I checked breakers and fuses, all were fine. I then switched to heat and the furnace wouldnt fire up. I know thermostats rarely fail, but at this point I cant find any other reason why both the central air unit, and furnace unit will not fire. This was a new construction home built about 5 years ago, and they went really cheap on some of the switches and dimmers that we have had to replace or upgrade. Any thoughts or ideas on what to check that Ive missed? The wall unit is a honeywell, dollar store variety that we never upgraded. There is no spark when moving the temp setting, nor the traditional "click" noise that accompanies the switch.

BTW, the whole unit is still under the new home warranty (sort of, for failures not caused by us) but they wont be available til at least tuesday, and here in TX, it is going to be in the 80s + all weekend long.


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## rakes9720 (Dec 13, 2006)

Sounds more like you have no power to the system. Did you check the fuse in the furnace? It powers the cooling too. If you have a volt meter, check the voltage (AC setting on meter) across thermostat connections R and C on the furnace control board. It should be 24VAC.


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## surferntx (Feb 24, 2007)

well the code flashing seems to say the same thing to check thermostat leads from the furnace, open fuse and such. Going to look into it in a few minutes...replaced the thermostat with a remote controlled unit anyway, couldnt resist.

Thanks for the help, hopefully this should knock it out.


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## surferntx (Feb 24, 2007)

well, replaced the 3 amp fuse, the code cleared, flipped on the breaker and turned on the ac...it popped another fuse. I suppose I will just have to wait for the ac guys to come look at it to find the short.


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## rakes9720 (Dec 13, 2006)

Just to possibly save some money, check the wires Y, G, R, and C around the board with the fuse for any crossed wires. If there aren't any call the HVAC company.


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## diywoman (Jan 4, 2007)

*Update!*

Well I said I would keep you up to date on the savings after putting my new thermo in....Well, bad timing really because Jan happened to be a VERY Cold month, so I really can't say I see the savings yet (not in my oil bill that is)...Perhaps this month I'll notice. I did find that I had the temperatures set a little higher than necessary, so I've lowered them and told my kids to put a sweater on and stop wearing the t-shirt!! ((GEESH))
I have the blower on 24/7 and I did notice that my hydro bill was a little less, I think the heat isnt' coming on as often because its getting good circulation. The thermo also has a usage display to show me in a day the total hours the heat kicked in. 

Well I see there are other problems to be solved here, so good luck!!! :thumbsup:


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## #CARRIERMAN (Oct 18, 2006)

HI diywoman Thanks again for letting us have your input. Hope all your other projects are going well. Hope to get to hear from you again. Good luck Rusty


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## KptnFmrs (May 9, 2007)

*No AC*

I changed out on old mercury switch thermostat back in December. The heater has worked fine. Now that I want AC, I am finding it does not work. I can hear the thermostat "click" when the temperature setting is reached, but the AC does not come on. 

The AC unit is a Rheem RACC-024JAS circc 1989
The furnace is a Lennox G8. It is the original furnace.. about 40 years old.

The new thermostat is a Lux TX500b.

30 vac comes from the transformer where the thermostat wiring is in the furnace. I can see where a pair of wires goes off toward the AC unit. All the wires seem to be intact and the transformer seems to be doing its job. 

On the thermostat, the red wire goes to the transformer, the yellow wire goes to the AC, the white wire goes to the furnace, the green wire goes to a post on the transformer, but I think it is just a terminal to connect it to the fan. The blue wire appears at the furnace, but is not wired to anything. It is wrapped around the the thermostat cable shielding. It is clear that it has been like that for a long time. I can only suppose that the old mercury switch thermostat did not require it.

I can still get the furnace to come on. 

I notice, also, that when the Fan switch is set to On (rather than Auto) it does not come on. It only works in Auto when the furnace kicks in.

Any ideas?

Ken


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## diywoman (Jan 4, 2007)

*Update*

Hi all,
I did update you a while back about the cost savings (if any) with installing my programmable thermostat. Well, I had previously reported a lower hydro bill, but as they like to estimate 2 and read the 3rd one, I got a real shock this month when I saw my bill. Now, I've had the blower going 24/7, but I found the air was circulating much better and the temp in the house was nice. My hydro bill jumped 3x compared to the last actual reading which was in Jan. Would just having the blower on 24/7 really cause it to suck that much hydro back? WOW. Needless to say, I now do NOT have it on 24/7 and with the cost of oil continuing to rise, electric heat even looks like a viable option. :huh: 
I think I need to get out my MONO and seal every crack I find. I must be missing some. (((3X's))) I'm still in shock.  
And how is it that my cost for hydro is less that it cost to deliver it. That's like buying a washer/dryer at the store and having them charge more for delivering it to your house than the items itself....HELLOOO!!!!????
**venting...oops**
Well, there you go. As promised, my feedback. All in all, the thermo was a great investment and it did help cut back on consumption. It's just hard to keep up with rising fuel costs, which is likely why they hiked the price to maximize on the savings we are getting with the thermo install...grrrr.


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## Superawe (Sep 4, 2007)

I have an American Standard unit built in 1994. I would like to upgrade to a progammable thermostat but the wiring is definitely a bit on the confusing side, when matching it to the avaiable thermostats. I have been looking at the honeywell/white rogers units for the upgrade, though I am not sure which one to get based on my configurations. Here is what I have now that have wires connect to them:

R - Red
O - Orange
G - Green
Y - Yellow
T - Tan
X2 - Black
B - Blue

The current mechanical thermostat does have aux and emergency heating with the indicator lights.

Thank ahead of time for any help!


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## kingkip (Sep 24, 2007)

*Any thoughts?*

I have an old mercury switch round dial type thermostat, and would like to change it to a programmable one. Any hardcore knowledge I need or is it just putting the wire together right and screwing back to the wall? Also any suggestions on thermostats would be great.


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## Dan1 (Oct 7, 2007)

Carrierman,

Perhaps you can help with my thermostat. I bought a White Rodgers 750 thermostat and it has terminals for G, Y, O, W, B and a jumpered RC and RH.

My old Carrier one had wires connected to W2, Y, R, E, C, L, and G. It's for a dual heat and A/C system.

Can you help? 
Thanks.


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## HVAC_NW (Oct 15, 2007)

On the reversing valve for heat pump, my LUX has two connections. O and B.

One being high on cool while the other is high on heat. Does the typical heat pump operate in cool or heat mode with the reversing valve input on low (no input) ?


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## 111jag (Oct 15, 2007)

*Wiring a Noma Thermostat*

I tried to install a programmable thermostat but I forgot to mark the wires when I disconnected the old thermostat. The air conditioner works fine, but the heating doesn't work. Find below the present hook up. Can someone help me out?
At the furnace I have:
R- Red wire
W - nothing is hooked up to this
C - Black wire
Y - White and Yellow wire
G - Green wire

At my thermostat I have:
G - Green wire
R - Red wire
Y - Yellow wire
W - White wire
Black wire not hooked up.
and I have another black wire that is not hooked to anything. I believe the black and white are the power lines.

There are no RC, RH or any of those types of codes on this thermostat. There is just the G,R,Y and W connections? and I have 6 possible wires to hook up to it (G,R,Y,W,thicker black, thinner black)

Can anybody help me out on this one?
R


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## #CARRIERMAN (Oct 18, 2006)

Hi again.

Its that time of the year again, I am noticing thermostats being changed again without verifying the problem. Look this one over, and as always. I will help you as I can.

Good luck
Rusty


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## happykraut (Nov 25, 2007)

*Carrier Furnace*

I have a 1975 Carrier and I believe the Pilot Assembly is bad. Pilot is on, blower blows but burner never fires up. Can anyone tell me if pat# LH 680005 and LH33JZ053 are the same. A local shop wanted $112 for the part(3wire) mine is a 2wire. I did find the 2 wire LH33jz053 for $66. Is it safe to buy the 2 wire or does anyone think that I have a different problem. I did take the thermocouple and heated it up with a torch, but I never got continuity between the two wires. It's 30F out. PLEASE help. Thanks in advance.


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## happykraut (Nov 25, 2007)

*Carrier Furnace*

I did some more trouble shooting and I'm totally convinced that the thermo couple is bad. I shorted it out and the burner fired up. Now I desperately need help buying the correct thermocouple over the internet. I have a Carrier Model #58GC100-2A-C, SN L391703 Series 221, Natural Gas furnace. Is LH33JZ053 the correct thermocouple. I have a two wire unit. Locally they want $112 for a 3 wire, but don't know the part number. I can buy one on the web for half that price , but I'm afraid that I might get the wrong one. CARRIERMAN where are you??? Thanks.


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## #CARRIERMAN (Oct 18, 2006)

Hi happykraut

The furnace you have just uses a standard either 24" or 30" thermocouple, nothing fancy. The pilot assy you have being two wire, all the two wires do is prove the flame for the main burner to operate. If the flame on your pilot is orange or any other color than blue. I would reccomend pulling the pilot assy out and cleaning it before I bougt any thing. Chances are this is all that needs to be done. As far as the LH680005 being the same, no it is not. The three wire pilot uses a electronic spark generator module which yours does not have. If you have to replace the pilot you will need to go back with the two wire pilot for your furnace to operate properly. Hope this helps, sorry it took me so long to get back to you.

Good luck
Rusty


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## happykraut (Nov 25, 2007)

*Carrier Furnace*

Rusty, thanks for the reply. I couldn't wait any longer(low 30's outside) and ordered the part this morning. I know for sure that the part is bad. It is not the usual thermocouple. It is the bimetal type. I suppose, cleaning may have helped. Bernie


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## slappy (Dec 5, 2007)

*Swapping out thermostats*

Saw this thread and thought it would be a good place to post. I have an oil-fired furnace with baseboard/radiator heating. My house is split into three zones, hence three thermostats. I want to replace at least two of these thermostats with a programmable model. I bought a Honeywell one at Lowes, fairly basic model, which is apparently for a single-stage system (which I think mine is).

I tried installing it this past weekend. I removed the old mercury-style one (American Standard), which revealed two wires: one red and one blue. The leads were not marked, so I studied the thermostat to see if I could figure out which wire was which (power vs. signal). While I was thinking about this, I turned the power to the furnace back on (so my kids didn't freeze) to heat the other two zones, leaving the 3rd zone wires hanging out of the wall.

Strangely, the radiator and baseboards in zone 3 continued to heat! The next day, I hooked up the new thermostat (crossing my fingers that the wires were connected to the correct terminals: I connected red to Rh and blue to W). I put the thermostat in manual override and set it to 60 degrees (essentially trying to shut off the heat to see if the thermostat was working). The radiators continued to heat. I reversed the wires and tried it the other way. Still heating. What gives?


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## stoop (Dec 5, 2007)

#CARRIERMAN said:


> Hi again.
> 
> Its that time of the year again, I am noticing thermostats being changed again without verifying the problem. Look this one over, and as always. I will help you as I can.
> 
> ...


Rusty,
My question concerns the location of a new thermostat. I just had a new Heat Pump and electric furnace installed and the installer relocated the thermostat to within one foot of the air intake. It was originally located approximately 25 feet away from the air intake, which was in my living room. Which is the proper location?
Thanks,
stoop


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## mrkool (Dec 3, 2007)

As close to the air intake as you can, so it's in the right place now.
The intake is where air form all over the house returns back to the system,so, naturally that where you'd want a thermostat (thermometer switch) to be located. Make sure they plugged up the hole where the thermostat wires go through the wall or it might not be accurate.


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## mrkool (Dec 3, 2007)

Hey Slappy,

First, if it still heats with the thermostat disconnected, then sounds like one of your valves isn't closing, so you may need to see about that first.

Then maybe the thermostat will work. BTW, you have it wired up right, for it's only a "on/off" switch, so, either wire on eiter terminal is fine(RH and W)


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## stoop (Dec 5, 2007)

mrkool said:


> As close to the air intake as you can, so it's in the right place now.
> The intake is where air form all over the house returns back to the system,so, naturally that where you'd want a thermostat (thermometer switch) to be located. Make sure they plugged up the hole where the thermostat wires go through the wall or it might not be accurate.


Appreciate the response & thanks for the info... 
Stoop


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## PartyLike1899 (Dec 11, 2007)

*Help Wiring Honeywell Thermostat*

I read the whole thread and I've decided to try replacing the stat anyway before calling the pros. My system has developed a tendency to kick the compressor on and off quickly when the house is at the target temp.

The system is a Bryant (Carrier) heat pump with E-heat from 1998.

The new stat is a Honeywell TH3210D, non-programmable.

The Bryant stat is wired:

O/W2 Orange
R Red
Y/Y2 Yellow
G Green
C Blue
W/W1 White

The Honeywell has R, Y, AUX, E, G, O, B, L, C, with a jumper for E/AUX.

So I figure the new wiring is

O Orange
R Red
Y Yellow
G Green
C Blue
??? White

My questions:

1) Where does the white wire go?
2) Shouldn't E/AUX be wired, and if so, should they be jumped?
3) Do I have the other wires (O,R,Y,G,C) right?

Thanks for your assistance.

Mark


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## redline (Mar 5, 2006)

:wink:


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## Eeek (May 12, 2008)

http://farm4.static.flickr.com/3230/2484906770_7e306de623_b.jpg 
This is my old thermostat. I took off the green g wire and thought it was a good idea to take a picture. http://farm3.static.flickr.com/2262/2484906824_30e8d5225c_b.jpg
Here is the new one. Wire g, c, r and w2 (on the old one) seem simple. I don't understand y, which is bridged on the old one to w1. So is y the new w on the new one? I hooked everything up, it blew hot air and I got sad and took it off. Anyone know where the wires go? This is for a 2 stage heat (norm and emer) and 1 cooling. This is all electric. Thanks ahead of time for you help!


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## #CARRIERMAN (Oct 18, 2006)

Hi Walker45

See if this helps with your question. If not post it back on the site and one of us can help. This nomenclature is to simplify the understanding of what is happening at a thermostat as well as help with the wiring. 

Good luck
Rusty


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## JasonTag (Jul 31, 2009)

Hello all.

Came across this forum while researching an issue and it seemed like a great place to ask my question.

I'm upgrading my old thermostat to a new digital one. I have oil heat and Burnham V8 Series burners.

The old thermostat was an ancient goldtone Honeywell round with B, R and W terminals at 8, 6 and 2 o'clock on the baseplate, respectively. The new one is a RiteTemp model i got from the Depot.

It's a two wire system coming out of the wall with one white and one red wire. On the old Honeywell, the white wire was connected to the R terminal and the red wire was connected to the B terminal. Nothing was connected to the W terminal.

This goes against most of what I've found online and even in the instructions for the new therm, which says the red wire should connect to the RH terminal and the white to the W terminal.

So I'm stumped and I'm really not in the mood to burn my house down so I was hoping you guys could help me out. There IS a B terminal on the new therm. Should I replicate the old wiring and hook the red wire to that and the white wire to the R? Or should I be following the instructions on the new therm?

Help!


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## Jimbo007 (Aug 27, 2009)

*YORK electric furnace to digital TStat question*



#CARRIERMAN said:


> Hi DIY,ers
> 
> Was hoping to see more visits on this topic, and even hoped for a few questions for mdshunk and myself. Hopefully the ones of you that visited got some insight, thats all that really matters.
> 
> ...


Hi Carrierman,
I have a YORK electric furnace model N2AHD14A06C. No A/C. 
My old Tstat has two wires. 
I've got a Noma digital Tstat, Multifunctional, and it has the ability to manual switch the blower on or leave in auto mode. 
My old Tstat had two wires of the multi wire harness connected.
I hope to connect the t-stat to the furnace via 'G' terminals at both ends. I'll use the green wire that isn't used. 

My Question: at the furnace can I assume that the 'G' terminal would allow for 'stay on' electronic activation of the blower from the manual switch at the TStat?

My Noma booklet has confirmed the 'G' is for the blower for a 3-wire configuration. And I pulled open the furnace's electrical box at the terminal and see that the 'G' and 3 other terminal posts are connected internally, with the other posts empty. Terminal 66 is HOT white wire to Tstat RH, terminal R is the black wire to Tstat W. Terminal B is connected internally, but not to the wire harness.


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## yuri (Nov 29, 2008)

Carrierman has not been seen for a long time (not by me anyway). NORMALLY you have R (hot) at the furnace board to R at the tstat. Which may have a jumper Rc/Rh. Then W to W and G to G. you must have 3 wires for the fan to work. Noma tstats are CR*P (cheap Chinese knockoffs, get what you pay for IMO) and I would return it and buy a decent Honeywell Focus or Vision Pro or you may be sorry.


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## Jimbo007 (Aug 27, 2009)

yuri said:


> Carrierman has not been seen for a long time (not by me anyway). NORMALLY you have R (hot) at the furnace board to R at the tstat. Which may have a jumper Rc/Rh. Then W to W and G to G. you must have 3 wires for the fan to work. Noma tstats are CR*P (cheap Chinese knockoffs, get what you pay for IMO) and I would return it and buy a decent Honeywell Focus or Vision Pro or you may be sorry.


Thanks OldPro.
The only two wiring colors that were attached to the old Honeywell 3 terminal TStat had wire White to terminal 'R' and wire Black to terminal 'W'. The 'Y' terminal unused. 
At the furnace board, wire white to terminal '66' which is jumpered with '60'.
Wire black to terminal 'R'.

Looking into the furnace box I have 4 terminals connected to the board:
66
B
R
G
The other terminals have nothing wired to their posts: O,W,X,Y and 55.

Using the box's ground as a return, I metered against the 66 and noted 'HOT'
and when I metered against 'R' got nothing.

One more note: the R seems to be connected directly with the 24V transformer.

I kept my old thermostat, and if it fails, I'll transfer back to the old.
My only concern is to blowing more than the transformer's fuse in the box. Like a relay... That's expensive, especially if I need to call in a tech.

As for a return. I bought it 2 years ago during the big sales. Just getting around to installing it. Doubtful I can return. At least there's a 4 yr warranty.

Thanks for the advice. I'll start shopping around for a better quality replacement.


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## yuri (Nov 29, 2008)

Post a pic of the wiring terminals as you got me curious. Some of those terminals are for a heat pump use. Not sure if someone altered your wiring and I cannot find a manual online. If you can post a pic of the wiring diagram for the furnace that will help. 98% or more of the equipment manufacturers use a standard RWYG configuration. Not sure what York was thinking with yours. One of your terminals should be a C (common terminal). I will find you a pic of a standard Lennox and post it. In Canada are you? Noma is Can Tire's favorite. R (hot) goes directly to one side of the transformer and the other side usually a yellow colored wire goes to C (common) on the terminal strip for your 24 volt supply. York is famous for using all black wires with numbers (PIA horrible).
When energized by the tstat: W to C is heating (24 volts) Y to C is cooling and G to C is fan all 24 volts on the terminal strip. From the tstat:
R =red
W=white
G=green
Y=yellow/blue is standard industry color codes 
http://tech.lennoxintl.com/PDFs/ES5.pdf
look at page 7 for a idea of how it "usually" is wired


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## Jimbo007 (Aug 27, 2009)

Yuri,
Excellent info! Standard codes is exactly what I'm looking for. Thank you!
I have no qualms with using the right wiring colors. I'm the second owner at this house. Suspect it was the builder/contractor installer that wired. Used white/black throughout for all including the HRV (this is separate). I guess didn't believe in using colors from the harness (furnace to Tstat). 
Pics will come this weekend when I burrow the camera...
CT is correct. Seems they buy lots of Chinese stuff. Even the Napoleon BBQ line they carry is from there.

I will try to post a diagram sooner. The inside of the furnace box is more challenging and a photo will be the easiest.
I've wired the TStat, (except for G), and will wait before powering the furnace again.

I'm in Ottawa,ON. Cool last night (+9C this morning). I'm sure you're getting that way too.


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## yuri (Nov 29, 2008)

You can interchange (buddy did it) R and W and it will work but not if you try use G. R needs to be hot. Thought you had lots of "hot air" in Ottawa or is the "Baron of boring running out"?


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## Jimbo007 (Aug 27, 2009)

*uploaded diagrams*



yuri said:


> Post a pic of the wiring terminals as you got me curious. Some of those terminals are for a heat pump use. Not sure if someone altered your wiring and I cannot find a manual online. If you can post a pic of the wiring diagram for the furnace that will help. 98% or more of the equipment manufacturers use a standard RWYG configuration. Not sure what York was thinking with yours. One of your terminals should be a C (common terminal). I will find you a pic of a standard Lennox and post it. In Canada are you? Noma is Can Tire's favorite. R (hot) goes directly to one side of the transformer and the other side usually a yellow colored wire goes to C (common) on the terminal strip for your 24 volt supply. York is famous for using all black wires with numbers (PIA horrible).
> When energized by the tstat: W to C is heating (24 volts) Y to C is cooling and G to C is fan all 24 volts on the terminal strip. From the tstat:
> R =red
> W=white
> ...


Here is diagrams (Visio) and chart that will be helpful.
for pics, I can't get them up here. I can email the 7M zip file to you if you'd like.


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## yuri (Nov 29, 2008)

Post the pics at Imageshack or Photobucket and put the links here. First diagram is missing info and unusual. Usually the fuse is between R and the transformer. Looks like they put it in the C side of the transformer which they call B. York is strange.

Looks like 60 and 66 feed your sequencers for heating, normal.


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## Jimbo007 (Aug 27, 2009)

Hi Yuri,

<grumble> sometimes I loose everything I've typed in under quick reply due to a time-out.... So Here I go again. This time I'll copy into my clipboard BEFORE clicking 'post quick reply'. 

I've posted the pics here: http://s747.photobucket.com/albums/xx114/b007jamesb-gmail_com/YORK Furnace box/

Please let me know by referencing a pic# if you need further more focused pictures inside the box. You should be able to zoom in on the pictures to see more detail...

I won't make changes to anything in the box as I'm not a trained technician. The wiring harness to the TStat could be modified, however, before doing this, I'd like to simply transpose the current wires to the new TStat. By connecting 66 to new TStat's RH, this should work for a two wire setup. The R would go to new TStat's W (according to TStat's diagram which indicates it as used for heating relay).

What I'm trying to add is a remote switch for blower from the new TStat, (New TStat's diagram indicates using its G 'Fan Relay'). 
So, which terminal at the box would permit this? Or do I have to go directly to the blower wires such as the blue wire which isn't connected to anything (see #YORK_5)

I appreciate all of your help thus far. It's great to have people such as you on this great site helping the general public, who wish to learn / save money and get satisfaction of 'doing it yourself'.


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## N01B4ME (Sep 1, 2009)

Carrierman,

Can you look at my post and help me?

http://www.diychatroom.com/f17/need-help-swapping-vision-pro-8320u1008-iaq-one-52121/


Thanks,
Tony


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## yuri (Nov 29, 2008)

His last post was in January/09. May not be back soon.


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## yuri (Nov 29, 2008)

Jimbo I hate to say this but somebody altered the wiring in your furnace. Those red wires are not from York and neither is that brown relay. Somebody added a toggle switch to the side of the furnace (for fan use?). I am wondering if the HRV is interlocked with the furnace. Without actually being there to do the job I cannot give you any SAFE advice that I would be comfortable with. I have some other Ontario posters/ folks who would like to see me if you all want to pay my airfare. LOL

York is very strange and does not use conventional wiring protocol. If you know of a HVAC tech who does work on the side perhaps he can sort it out for you. If we start changing wiring damage can occur. The elements and sequencers should be checked annually so paying for a tech is not a bad idea anyway.


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## Jimbo007 (Aug 27, 2009)

Thanks for your help, and appreciate the candidness. 
HRV is completely separate. It has it's own humistat on a different set of wiring. (Two wires, not part of the harness). My basement ceiling isn't finished, so I can follow and ascertain the wiring there. 
Service is expensive here in Ontario, (compared to Montreal, where I was originally from). Mind you, it doesn't help when you live outside the city prime, and the extra mileage they need to drive costs more.
Generally I wait for something to break before calling in someone. I have a secondary heating source just in case.


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## shadow82399 (Sep 20, 2009)

*3 wire multi zone...*

Anyone know if a 3 wire multi zone (only replacing 2 zones) can be replaced with any thermostat? I have a gas boiler hot water baseboard system. The wires are red, white and blue, but every thermostat I buy has 4-5 connections possible and nothing in the instructions about if you only have 3 wires.


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