Question about Goodman GMS90703BXA Heater

1 Answer

Installing a stat to a furnance

Need step by step on installing a thermastat to a two stage heating and cooling unit. I have installed a five wire line, or do i need more lines.

Posted by on

1 Answer

  • Level 1:

    An expert who has achieved level 1.


    An expert that hasĀ over 10 points.


    An expert whose answer gotĀ voted for 2 times.

    Problem Solver:

    An expert who has answered 5 questions.

  • Contributor
  • 15 Answers

You need a 7 conductor minimum, 8 will suffice.

Depending on what type of thermostat you are using, hard wired or battery will make a difference, some model thermostats have a "C" on the terminal strip regardless of the power being supplied to the thermostat. If your Thermostat does NOT have a "C", and the furnace does not require a common, then disregard that terminal.
The Terminal strip on the thermostat and the terminal board on the furnace should be close to this, and let’s assume you have 2 stages of cooling as well. This is a general rule of thumb for the wiring and their correct place.

R - 24VAC
W - Heat
G- Fan
Y - Cooling
W1- Stage 2 Heat
Y1 - Stage 2 Cooling
C - Common

Posted on Dec 02, 2008

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Had new heating installed an got honeywell thermastat .weet to put heating on today for firsf time heating wont come on

If it was changed during the cooling season, the first thing I'd check would be for a jumper between the Rc and Rh terminals on the thermostat sub base. If not there, install a short jumper to power the heat side of the system. If there IS a separate wire on each of the Rc and Rh terminals, you have to check to make sure there are TWO transformers in the circuit, one for heating, one for cooling. Most new systems are NOT set up this way, but there a few dinosaurs out there. If there ARE two transformers, do NOT connect the jumper or one of the transformers will immediately burn out. If there ARE two, proceed to troubleshoot the heat side of the control circuit. Look for a secondary fuse or tiny circuit breaker, loose or broken wire on Rh, W1 on t-stat or in furnace. Then call a service tech....If you are not capable of performing the above, call the tech first.

Aug 10, 2014 | Honeywell Heating & Cooling


Thermostat Wiring and Terminal Designations

Here is a list of each common terminal and what their commonly used for. Also listed is what colors are commonly used. NEVER ASSUME these are what you have. Verify all your wires by following each to each piece of equipment. This will help you to be able to match your equipment with the terminal.

- R, Rc, Rh Red wire, hot side of transformer
- C various color wires Usually the common side of transformer
- Y Yellow wire, Energizes the compressor, cooling or heating and cooling for heat pumps
- W White wire, heating for most units
- G Green wire, energizes the fan or blower relay.
- O Orange wire, energizes cooling on most heat pump units
- B Blue and sometimes Orange wire, energizes heat on most heat pump units
- B or X Blue, Black, or Brown wire, the common side of the transformer when the t-stat needs a common. Some brands use B as the common (York, GE, and Trane)
- E Pink, Gray or Tan wires, Emergency heat relay on heat pumps with auxiliary heat
- T Tan or Gray wires, For units with outdoor anticipator reset control (Trane, American Standard, GE, and Carrier)
- W2 Pink, or Brown wires energizes second stage heating on 2 stage units
- Y2 Blue or Pink wires, energizes second stage cooling on 2 stage units
- L Can be most any color, energizes service indicator lamp on units that are equipped with that.

The wires that always cause the most confusion are the B and X wires.
Check out the B terminal first. The NEMA standard for the B terminal to be the heating changeover valve but with some units it is different.

Trane, GE, York and some other manufactures which includes older Honeywell thermostats often use it for the common side of the transformer.
“X” Usually is the standard for common, but just like “B” some manufactures do use “X” or “X2” as the terminal for the emergency heat relay.

on Dec 12, 2009 | Heating & Cooling

1 Answer

I installed the RTH 7400D thermostat according to wire direction for heat pump. I have wires C,G,Y,O,R,L AND THE L IS JUMPED TO AUX. THE BLOWER COMES ON BUT AFTER THE ROOM GET TO TEMPETURE THE UNIT SHUT...

did you set dip switchs on new stat for ht pump with electric ht back up if that is your type of heat. newer t stats might not have dip switchs but a sequence of programing steps to set up new stat to match your needs ps when set up correctly the fan will run for a few minutes after cycle over to discharge residual heat from unit n ducts .

Nov 04, 2013 | Heating & Cooling

1 Answer

No Auxiliaty heat with new thermostat

The Vision Pro is a great t-stat and I have installed many of them with great results. I am wondering though if it is set up correctly. Did you go in and make sure that it is set for heat pump and for 2 stage heating? Look on the instructions how to get into the advance installer options. Go through that meanu and make sure that everything ig set correctly for your type of heating system and that it is set for 2 stage heating. From what you have here and I can tell the wiring should be okay that is why I think that it is in the t-stat programming.

Nov 15, 2009 | Honeywell Electronic Programmable...

1 Answer

There is five wires yellow, green, red, white, the problem that we a facing is to connect these wire into the honeywell theromostat RTH3100C1002-0916

yellow is the cool wire, green is the fan wire, white is the heat wire, red is the power wire. these stats should have a 1 letter icon ,r for red on stat y for yellow and so on ,make sure that Rc and RH are jumpered and install batteris if needed

Sep 29, 2009 | Honeywell Electronic Programmable...

1 Answer

Thermastat reads 2 only, and air conditioner is not working

without more info it sounds like one leg on led readout went bad , i hate to say but you need to replace t-stat, in the mean time if you go to breaker panel and shut off power to both the (a/h and cond.)inside and outside unit take t-stat off the wall and disconnect all wires there should be green,red,yellow and white wires.If this is the case take yellow,red & green and twist these 3 together and put a wir nut on them.then turn power on to both units and this will get you a/c the only problem with this is, unit will run constantly until you either diconnect wires or turn power back off. hope this helps

Sep 12, 2009 | Honeywell Electronic Programmable...

1 Answer

I am installing a Honeywell T841 onto existing RGYW wiring. The fan kicks on, but I notice the air conditioner is not running. Were one or more of these supposed to go on the W2 or B terminals? Thanks!

Need to have more numbers in model number to be sure There's about 30 T841 t'stats and some are1, 2, and 3 stage heat pump and some 1, 2, and 3stage AC.
If you have
R to transformer
G to fan relay
Y to contactor in outdoor unit
W to Gas valve
You have the thermostat wired right.
Depending on the T'stat B could be the common side of the transformer or 2nd stage heat.
W2 terminal are for 2nd stage heat
You need to put the thermostat on cool and lower the setting to bring on the cooling. Then go outside and see if you have power to the outdoor unit and 24 volts to the contactor coil.

Sep 06, 2009 | Honeywell Electronic Programmable...

2 Answers

Programmable T stat

your trane heat pump energizes the reversing valve with O - orange y - is to turn on the unit make sure you have your orange wire hooked up and the tstat programming set to heatpump otherwise your reversing valve might be bad

Jun 30, 2009 | Honeywell Electronic Programmable...

1 Answer

Fuse Blows when diagramed wiring is used on GMP125-5

i would check your thermastat wiring if you blow the fuse you have a dead short those fuses are saving you alot of money. remove all wires from terminals for t stat on furnance and jump between r and w if it works your problem is in wiring ..........

Feb 26, 2009 | Goodman GMS90703BXA Heater

1 Answer

My heat wont turn off

Whan your room is up to temp or room is set at 70 and your stat is at 70 do you hear the stat click off .if not its a bad stat. you will have a little flam on your stat that should go off also

Dec 28, 2008 | Honeywell CT87B ROUND HEATING&COOLING...

Not finding what you are looking for?
Goodman GMS90703BXA Heater Logo

Related Topics:

85 people viewed this question

Ask a Question

Usually answered in minutes!

Top Goodman Heating & Cooling Experts

Dan Webster
Dan Webster

Level 3 Expert

8205 Answers


Level 3 Expert

2046 Answers

Brandon Berry
Brandon Berry

Level 2 Expert

407 Answers

Are you a Goodman Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides