Questions tagged [thermostat]

Mechanical or electrical device used to control a heating, ventilation, and air conditioning (HVAC) system, or other temperature reliant system.

Filter by
Sorted by
Tagged with
2
votes
1answer
345 views

1 nest to control all vales on UFH manifold?

We are having an extension done and intend on having all underfloor heating in the new area. Currently we have a valiant combi boiler supplying the main house which has been T'd off with a valve for ...
1
vote
1answer
723 views

Need help adding a C wire for a wifi thermostat

With the increasing popularity of wifi thermostats I know this question has been asked many times, however I'll ask it again fr my specific situation. How do I add a "C" wire to my existing air ...
1
vote
1answer
245 views

How to wire programmable thermostat that doesn't have an E termimal

I am trying to replace a manual with programmable thermostat that is missing emergency heat (E) terminal. There are bits and pieces of information I have gathered but am still not clear. Can I leave ...
0
votes
1answer
434 views

How to simply turn heating on/off with VRT 340f thermostat?

I've just moved into a new house and it has a Valiant boiler with a VRT 340f thermostat and I have to say it is completely perplexing even after having read the manual several times! It seems ...
3
votes
1answer
622 views

New Thermostat Ecobee3 to Old Galaxy GG-75 boiler - Needs common wire

I would like to replace my old thermostat with a new Ecobee3 thermostat. HVAC system is a Slantfin Galaxy GG75 boiler - single zone. (No air conditioner.) Current set-up has only a red and white ...
1
vote
0answers
7k views

My furnace has a C - common wire but air conditioner uses it - how to hook up smart thermostat?

I bought an ecobee3 smart thermostat which requires the C wire. At my furnace there is no circuit board but there was a diagram and I was able to locate the C - common wire, but it seems to be used ...
0
votes
2answers
1k views

How can I know if my boiler is supported by Nest 3rd Gen thermostat?

Here are the pics How do I know if my hot water boiler is compatible with Nests domestic hot water control
1
vote
3answers
13k views

Thermostat is completely blank. How to troubleshoot

I have a thermostat that is completely blank (no display). I'd like to troubleshoot it myself even if I do ultimately hire a pro! We're in sunny southern california, so it's possible it's had no ...
-1
votes
1answer
74 views

Thermostat/electrical

I have a Honeywell RTH2510 series thermostat that I want to install in a condo with baseboard heating. I took off the very old thermostat that was previously installed and there are only two very ...
0
votes
2answers
347 views

Rented Property: Install Nest

I have a Worcester boiler (Greenstar HE?), with a TR2 thermostat. I was looking at replacing the thermostat with a Nest (or equivalent). To complicate matters, I'm in a rented property, so I cannot ...
1
vote
2answers
217 views

Electric baseboard wiring

I have a 240v 1500w 6.5a electric baseboard heater with a wall mounted thermostat. What I found out is that the the thermostat and all the outlets in the room are on the same 20a breaker with this ...
0
votes
2answers
2k views

Can I shorten my in floor heating cable?

Just wiring up an in floor heating thermostat. I have two separate two wires going into my flooring as well as another coming from the panel. I am wondering about the two wires going down to the ...
2
votes
1answer
162 views

0v at DC thermostat terminal in furnace

I have an old (mid 80s) Rheem gas furnace I hope will last me through at least one more California winter. It's been known to go down into the upper fifties, so it has its work cut out for it. In any ...
0
votes
1answer
583 views

Can I share “C” wire on two thermostats?

I am wiring a second thermostat right next to the original one. The new needs a C wire. Can I share it from the old one? Old: 8 wires, used to run heat pump (w/ heating and AC) and backup oil. Now ...
1
vote
3answers
35k views

Correct Wiring for Furnace Blower Motor

After getting my furnace blower motor replaced, it now runs only in the following scenarios: 1. Mode "Cool" Fan "Auto" 2. Mode "Cool" Fan "On" 3. Mode "Heat" Fan "On" In other words it will not run ...
3
votes
3answers
55k views

Hvac Fan only blows in 'fan on' mode while heating

Our HVAC Fan only blows in 'fan on' mode while heating. In other words the fan will not blow in heat mode if switched to "fan auto". Both fan on and fan auto modes work when cooling. See image below, ...
1
vote
1answer
122 views

electrical range - oven temperature not set

I have a pretty old electrical range GeneralElectric RCBS536DN2WW. The problem is that I can't use the oven: whenever I set the temperature with a temperature knob, it raises up rapidly and everything ...
1
vote
1answer
150 views

Find the model for an unknown (non-Häger) wall thermostat?

I recently bought a house, after years in a flat. Many things are novel to me, especially the heating system. The digital thermostat is of an unknown brand, the former owner could not tell me (I ...
-1
votes
1answer
715 views

Can I use a ground instead of a dedicated C wire for a thermostat

My new wi-fi thermostat requires a common wire coming from the 24 volt transformer. Rather than running an additional wire can I ground the common side of the transformer to the building steel ( this ...
0
votes
1answer
77 views

How does my Boiler work with my Baseboard and thermostat

In the apartment I am at I am just wondering how the boiler system works between all the units. Apparently its one water pipe going the whole perimeter of the floor but each apartment has it's own ...
2
votes
1answer
554 views

New Thermostat installed but compressor comes on immediately

I have a new Insteon Thermostat that I'm using to replace my prior Honeywell t-stat. This is installed to a relatively new HVAC system (both AC and Heat) that DOES have a "c" wire. I've attached the ...
0
votes
3answers
13k views

Thermostat wiring splice

I need to relocate a thermostat and have the additional wire needed but I am not sure of the ideal way to "join" the cable sections. Will using wire nuts and zip tie be good enough?
1
vote
0answers
47 views

How to connect 4 fan coils with one wall control thermostat?

I have 4 fan coils (Sabiana sk-22)and I want to connect them with one wall control thermostat. How can I do?
0
votes
2answers
245 views

Is the Thermostat Wiring Correct

When I moved in to the house the first thing I changed was the old mercury style T-stat to a digital one, I went wire for wire, and it has works (knocks on wood) so far. Now that I have been reading ...
0
votes
1answer
1k views

Where do attach C wire on my boiler?

I need to add a C wire to use my wifi thermostat. I have a 2 wire thermostat now. There is a third wire in the wall which runs to the basement where it is cut off. I can easily extend it to the boiler....
0
votes
1answer
3k views

Furnace reaches temp, shuts off but wont come back on

I have an American Standard furnace (natural gas)with a manufacture date of 2004. The thing won't come on unless I power it off (have a switch right beside it that serves this purpose), let the fan ...
0
votes
1answer
1k views

central A/C Turns back on 30 seconds after shutting off

First of all, the a/c system is probably 30 yrs old. The outside unit stays running when the inside unit shuts off. After about 30 seconds, the inside unit turns back on again, and will sometimes only ...
1
vote
1answer
414 views

When running AC, Heat turns on once thermostat reaches desired temperature

I just recently installed a new wifi thermostat for my system. I went from a Trane to a Honeywell. I followed the instructions and put the wires in the right terminals (i believe) Everything is ...
0
votes
1answer
727 views

Help installing new thermostat

disclaimer, this is my first attempt at doing any type of electrical work, so apologies in advance for any wrong terminology :) I attempted to install a new Honeywell programmable thermostat. When I ...
1
vote
2answers
17k views

trouble shoot air conditioning thermostat

my compressor outside is not kicking in. Here's the sequence of events: I came home and the thermostat - a Honeywell LCD - was no more numbers and the battery indicator was flashing. replaced the ...
4
votes
3answers
13k views

How can I wire my WIFI thermostat to control my millivolt fireplace?

I have a gas fireplace that has an millivolt on/off switch on my wall (and a remote that includes flame on/off, a countdown timer and a thermostatic flame control). I want to be able to program ...
1
vote
1answer
514 views

switching out a heat/cool only thermostat to one with “auto” feature

I have a Honeywell deluxe programmable thermostat with a sub-base... Sub-base: 32207415-011/0008 Model: T8602D2000 The terminals that are used currently are: R W Y G (RC and O are not used) My ...
1
vote
1answer
194 views

Thermostat broken or central air system?

Thermostat works sometimes, other times I have to shake the switch to get the air conditioner working. Is this a problem with the thermostat or the central air system? Thermostat is about 15 years old,...
3
votes
1answer
197 views

Can't get fan working on thermostat

I recently purchased a new thermostat. My old thermostat worked for heat (no AC either) but the fan wouldn't go on when I turned to "On" (in hopes to move some cool air from the basement up during the ...
1
vote
0answers
60 views

Should I install a doorway fan or dehumidifier?

I have central air in a rancher (one floor), and the living room is on one end of the house. That room is on a slab, and has always been noticeably hotter in the summer and colder in the winter than ...
0
votes
1answer
2k views

Honeywell RTH7600 does not responsd

Just installed new Honeywell RTH7600. All wires are correct and the unit displays fine. The issue is that heater and AC do not turn on at all. I even put the fan to ON instead of AUTO and that does ...
0
votes
1answer
2k views

AC continues to run for several minutes after shutting off

When I turn off the AC it continues to blow cold air for several minutes. I realize this may be an energy savings feature, but I'd like to know if it is possible to disable it. In other words, what I'...
1
vote
2answers
6k views

Can I use a WiFi thermostat without a C wire?

I have a very old Honeywell programmable thermostat. I am going to replace it with a White-Rodgers UP500W Emerson Sensi WiFi Thermostat. I just want to know if the WiFi unit will work without a C ...
0
votes
0answers
5k views

AC Compressor outside is not running with new thermostat

my old thermostat stopped working, so I purchased a new one to replace that. The old one was powered by two AA batteries. A green wire connected to G, a white wire connected to W, a blue wire ...
0
votes
1answer
36 views

Issue with Thermostat

I bought and installed a Trueway thermostat before 2 years. It was working well for the past years. But then a twist! the thermostat started to go nuts, the tempeature would race over 60 degree, even ...
1
vote
4answers
5k views

How to override an attic thermostat with a wall switch?

I want to install a fan in my attic. I want the fan to be controlled by a thermostat in the attic, but I want the ability to bypass or override the fan from within my house. Ideally I would like to ...
0
votes
1answer
1k views

Changing Trane Baystat240a to another thermostat

I want to change my current thermostat to a programmable electric one (no batteries). Could someone verify if it does have a common wire and if all wiring could fit modern thermostats? Looking at the ...
1
vote
2answers
27k views

Why “W” (heat contactor) and “E” Aux Heat connected in Thermostat

I'm trying to update my thermostat to one that has a scheduling feature. My plan is to just copy how it was hooked up in an old 129N Thermostat from Armstrong however, I can't figure out why the "W" ...
0
votes
4answers
4k views

G to C trick not working for cooling. Honeywell RTH9080WF

My electric furnace has no c terminal. Furnace is heat & cool both. (Lennox Electric Fan coil Model CBS18-21-3P). I installed Honeywell RTH9080WF. I switched G to C on my thermostat and got the ...
0
votes
1answer
495 views

Where is my Common Wire? [duplicate]

I purchased a wifi thermostat and cannot located the common wire. My unit is old and is a Coleman 70 with no terminals inside labeling the wires. As you can see in the second image, there is a blue ...
1
vote
1answer
875 views

How can I tell if I have a C wire?

Below is a photo of my current thermostat's wiring. I have a few questions: Why is the RC and RH are bridged with a black wire? I have an unused blue wire. Is there a way to find its function? Could ...
1
vote
1answer
3k views

Can I connect two wires to a single screw terminal in my HVAC system?

I am installing a new honeywell WiFi thermostat but the old battery operated thermostat had batteries and no "C" wire. I look at both the thermostat and the air handler and found an extra un-used blue ...
2
votes
1answer
394 views

How to Change Chinese HVAC Thermostat

I am looking to put Nest thermostats in the house, I have now found out my entire house (one in each room, 6 of them) has been wired with HVAC Chinese U12A UNIVERSAL A/C CONTROL SYSTEM urrgh – they ...
1
vote
2answers
5k views

Smart Thermostat - No C-Wire - No Controller Board

This one seems to be a little different from previous questions on the subject. Here is the dilemma, I don't see a transformer. I have included a few pics. There are Three wire bundles. For ease we ...
1
vote
1answer
425 views

How can I disable cooling with a White Rodgers thermostat?

1F56W-444 White Rodgers Thermostat I am fairly sure this is the thermostat that I have. How do I disconnect the cooler/air-conditioner as to avoid my penguin visiting relative waking me to 55°F ...