There are stats that can control both heat and cooling with only 4 wires. Some can do it with less.
Their mistake.
I recently had a company (Sears) install central AC in my home. They retrofit the coils to my existing furnace. They also installed a new thermostat.
The air works great, but the heat no longer comes on. I have looked at all the wires in the back of the thermostat and inside the furnace itself. According to the manual for the thermostat - E/W1 is supposed to be used for controlling Emer/Stage 1 heating. I have no wire on this lead. Could this be the cause of my furnace not kicking on? I am fairly clever when it comes to electronics, but I don't know how it could possibly turn on if there is no control wire for the furnace.
The wires that are hooked up are the
(R) Red -red wire (24 V for powering the thermostat)
(C) Common - white wire (actually it is hooked up to my furnace W post - I would think this is the control wire, but they are using it as a ground)
(Y1) blue wire - Compressor control wire
(G) green wire - fan control
There is not another wire in the wall. I feel that they hooked the air up and did not have enough wires to hook up both air and heat, and rather than run a new cable that has 5 wires - they figured "It will be another 2 months before he finds out. Hehehehe (sinister laugh).
Is there any way that the system could be connected properly using only 4 wires? From my calculations, I think that they would need a minimum of 5 to control my single stage heat and single stage air.
I have them coming out tomorrow and would like some ammo for them. If it is a problem with the furnace, it is my dime - if it is an issue with the installation, it is on Sear's dime.
Any help is appreciated.
Last edited by ualr_jmjones; 10-05-2009 at 04:45 PM. Reason: oops
There are stats that can control both heat and cooling with only 4 wires. Some can do it with less.
Their mistake.
I have never had any issue with my furnace. I believe it to be 7 years old (Carrier natural gas furnace), I have lived in the house for two years.
I am quite confident that this thermostat is not a fancy one that can do it with less wires.
I knew nothing about HVAC until I found this issue and their tech support wasn't very helpful, so I started digging around for something obvious - like a wire not connected properly, etc. When I found that all the wires were in their correct spaces, I started to trace them out. Every letter on the furnace mates up to a wire on the thermostat. The stat has other capabilities as it can be used on dual stage heating and cooling - so I expected there to be some empty terminals on it.
But, without the E/W1 terminal being connected to anything, and the manual clearly states that it is the "Emer / Stage 1 Heating" terminal - I saw no possibility of ever getting the furnace to kick on. Is that assumption correct.
Oh, and thanks for all the HVAC people out there that do a good job at what they do. When you find someone that doesn't it really pisses you off - so cheers to all that do a good job.
They need to either use a different stat, or pull another wire bundle for it to work.
I would give them a chance to fix it. It may have just been an honest mistake. I've put wires where they didn't belong before myself.
Zach
Well, I'm not a pro, but I know W controls the furnace so I think it's unlikely to work with 4 wires if your tstat needs a a common. If you don't need the common on your stat I'll take a guess that they will probably just move the white wire from C to W on the tstat.
If pulling another wire is going to cost you, I'd recommend looking at the Honeywell VisonPro IAQ thermostat instead. I think it can run on 3 wires (though I'm not sure just how they manage that).
Oh, and if they make the furnace work, I'd check it to make sure the AC still works before they leave.
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Ha ha ha! You called Sears...
Not as lean, not as mean, but I'm still a hardcore, ass-kicking, hard charging Marine! Oohrah!
UPDATE
I just got off the phone with the service guy that is on his way. He agrees that there really should be a wire coming out of the E/W1 on the stat. BUT, he says he is going to move the white wire from (C) on the stat to the (E/W1) terminal. His logic is that my stat has batteries and therefor does not need the Common.
My question is....
Is this a half ass solution? Does this mean that my stat will run solely on batteries? When the common is connected, is it running off of the power from the furnace (DC) that is powered by my house (AC), thus only running off of batteries when the power is out? If my batteries go dead, does that mean I have no heat or air? When I replace my batteries, do I lose all my programming?
Ultimately, should I insist that another wire is run, so I can have 5 wires instead of 4 and power the stat via the house wiring and not the batteries? He will be here in two hours (supposedly)
Hindsight being 20/20 - probably wouldn't do it again, but they had no interest no payments for a year, and the unit has a 10 year warranty. I am hoping that Sears can make it though this economy. I was leary of some of the local shops that came out to give an estimate as I wasn't sure they would be around to do any warranty repairs.Ha ha ha! You called Sears...
Now, had I known that this warranty == headaches - I would have gone with someone else.
Thank you for suggesting the option of changing out the stat and board, but I doubt they will do this since it is a warranty repair, but I will suggest it to the repairman.
What thermostat do you have? If it does "power stealing" to conserve battery life, then yes, your stat will be running on batts and they will go dead much sooner. Of course, with C-stat wired to W-furn, the power stealing may not have worked anyway. BTW, my stat does not require C to work propoerly, but needs it for power stealing to conserve battery life and enable the continuous backlight.
I suggest you read your contract to see if upgrading your wiring was part of the deal, but I doubt it. I mean, if you were in the business, would you include home wiring upgrades as part of the deal, not knowing what the wiring upgrade would cost to do? I wouldn't. On the other hand, they should have told you up front that they needed to check your wiring to see if it will support the installtion, and if it didn't, tell you what it would cost to upgrade it. If it turns out you need new wire, and they never talked to you about that, I think it would be reasonable to negotiate some sort of deal with Sears to remedy the situation. I mean really, if you needed new wiring they should have told you that BEFORE you accepted the contract.
I really doubt if they would throw in a new programmable stat as part of the deal. Personally (if it was me doing it), if the wiring change doesn't work, and they don't offer to do anything else, I would get a new stat that will run on 4 wires or less. There are other advantages to a stat like the VisionPro IAQ. For example, you can program it to circulate your air when heat/cool are not required, which can help eliminate hot and cold spots in your house. You could also run a humidifier from it.
Oh, and I would negotiate with Sears. The repair guy is probably just a contractor with little authority to give you anything much.
The stat is a Braeburn Premier Series 5200.
The manual says that it is not required for battery only operation. I would assume that it could be a "power-stealing" type, or it can run without it.
How long do these batteries typically last in a thermostat? Can lithiums be used in it? I have had good luck with the Energizer Lithiums, they last forever in other devices around the house.
If they last around a year, then it really isn't an issue for me running it off of them. If I am going to have to replace the batteries every 3 months, then it is an issue for me.
The quote they gave me was for the complete end to end installation, including wiring if needed. Since they had 4 wires, they decided they didn't need the extra wires - Is that decision one that they should make or should I make that call? They were prepared to run new wires during the original install.
The Bareburn 5200 manual states "Transformer Common connection not required for battery-only operation of thermostat", but the manual also describes the batteries as "back-up". Also, it states, "This thermostat requires two (2) properly installed “AA” Alkaline batteries to maintain the system clock and to provide power for the thermostat if 24 volt AC power is not connected to the terminal block". This means the batteries ARE proeviding power when no AC is connected.
Note also this statement in troubleshooting, "Symptom: Thermostat display is blank.
Potential Solution: It is possible that AC power is not present at the thermostat and the batteries are drained. Check fuse, circuit breaker and thermostat wiring as appropriate to verify AC power is available. Replace batteries before reprogramming thermostat. (see section 6). If AC power is present, call a professional service technician to verify thermostat and system performance."
All this strongly implies that the stat runs on AC power to conserve battery life, and having no AC power to the stat WILL drain the batteries much faster. The batteries are also clearly stated "for back-up".
If the backlight is used a lot, or is on continuously, the batteries would surely die sooner. I see this stat has NVRAM, so the setting will not be lost when the batteries go dead.
Again, if this was me - if the contract included thermostat wiring, and my stat manual read like this one (I.E. the batteries will go dead sooner without the C connection), then I would ask them to put in the extra wire. You'd be surprized what you can get sometimes with a clear and concise argument.
Thanks everyone, my appointment was for 9 this morning, but then got moved to 11, now it is moved to 12:30. Something about taking a wrong turn or something.
I will let you know how it works out.
The conversation might go like this:
Repair Guy: I fixed the wires so your heat will work. Your thermostat can run on batteries so you don't need the C connection for AC power to the stat.
Me: The batteries are back-up, and will go dead much sooner if no AC power is wired. The contract states that you will install any necessary wiring, and you knew which thermostat I have.
Repair Guy: Sorry, they just told me to fix the heat and now it works. Your thermostat will work fine on batteries. The manual says it will.
Me: OK, have a nice day.
This is when I call Sears Customer Service.
They put this thermostat in, so they should know that it uses the battery as a backup. The manual does state
"This thermostat requires 2 AA batteries to maintain the system clock and to provide power for the thermostat if 24 volt AC power is not connected to the terminal block"
I suspect that they will use this as their argument, however; I feel that this is not the best way to install the unit. According to the contract, there are line items for the compressor, coils, fan, and "Installation". When I spoke with the salesperson, he indicated that any wiring would be covered by the "Installation" item.
I would hope that they just agree with me and run the wire without any incident, since they screwed up my install in the first place and took 4 days to do anything about it. It has snowed twice and it gets down to 50 degrees in my house. I have a pregnant wife, but she did not mind the cold temps.
I don't think that the wire run would be that difficult and I would be willing to help the guy. If he doesn't run the wire, I will more than likely get my fish tape out and run it my damn self. I am NOT going to call their customer support since they are s#@t.
It comes down to an OK installation vs. an ideal installation. I don't cut corners so the OK installation is not good enough for me when it just takes a little bit more effort to make it an ideal installation. When I sell the house, I don't want to tell the new buyers "you really have to watch the battery indicator or you will end up in a hot/cold house when you wake up" - that just seems kind of ghetto to me.
The guy coming to repair is the same guy that installed the system, so I may shame him in to doing it right. I have a work order that he signed off on that states that he checked furnace operation successfully twice before he left.
Hopefully this will be me by the end of the day --->
Not uncommon to use a battery operated thermostat.
Not aware of any battery operated thermostat, that is power stealing. Some may be confused on what power stealing is. And using incorrect terminology.
If they simply switch it to battery operated only. Just change the batteries every year.
If you read the manual for the Braeburn 5200, it's true that it doesn't explicitly state that it is using AC power to prolong battery life, but it's strongly implied IMO. The batteries are referred to as "back-up" on the first page.
While not relevant to the OPs problem, the White-Rodgers 1F95-1291 is one battery-powered stat that does use power stealing. The installation instructions for this stat are very clear on this (unlike the Braeburn 5200 instructions which are not).
http://www.white-rodgers.com/wrdhom/.../0037-6914.pdf
This stat actually has 3 modes - battery powered (no 24V connected), hard-wired with battery back-up (24V with C connection), and battery powered with power stealing assist (24V but no C connection, runs an batteries AND 24V from Rh or Rc). The manual clearly states that the power stealing assist mode prolongs battery life.