Hello,

I purchased a Honeywell RTH230B programmable thermostat to replace an old round style Honeywell model. My problem is that after installing the unit only the heat works and not the AC. The wires that were hooked up to the old thermostat are as follows:

1. Green
2. Yellow
3. White
4. Red
5. Orange
NOTE: There are also a blue and black wire that are present but never attached to the old thermostat.

So... I placed the proper colors to their proper areas in the new Honeywell RTH230B model. However, the instructions say there should be two red wires so I placed the orange wire in the RED-C slot and the red wire in the RED-H slot. Again, the heat works fine but no AC. Should I place the blue or black wire in the RED-C slot instead? I'm totally confused as to why this is not working. Any advice would be great appreciated.

Thank you.

Remove orange wire and jump RH and RC. See if that corrects the problem. Your manual for the thermostat is below.
Is your system a gas fired furnace with A/C? It would be nice to know since different types of units will be wired differently.


http://customer.honeywell.com/techlit/pdf/69-0000s/69-1800.pdf

Remove orange wire and jump RH and RC. See if that corrects the problem. Your manual for the thermostat is below.
Is your system a gas fired furnace with A/C? It would be nice to know since different types of units will be wired differently.


http://customer.honeywell.com/techlit/pdf/69-0000s/69-1800.pdf


The system is a gas furnace. I have an A/C unit outside which connects into the furnace and then blows cool air throughout the house. The Honeywell manual says not to use the RH and RC jumper for 2 or 5 wire installations. Please advise if you still recommend removing the orange wire from the RC slot and then placing the jumper in the slot connecting to the RH slot.

Thank you.

The system is a gas furnace. I have an A/C unit outside which connects into the furnance and then blows cool air throughout the house. The Honeywell manual says not to use the RH and RC jumper for 2 or 5 wire installations. Please advise if you still recommend removing the orange wire from the RC slot and then placing the jumper in the slot connecting to the RH slot.

Thank you.


I read the Honeywell manual.
You did not tell me where the wires were placed on the old thermostat so I have no idea what orange is actually used for.
The color code is not always followed and without the knowledge of where the wires were connected to the old thermostat makes being accurate impossible.
I need to know what the orange wire was connected to on the old thermostat or you will need to track down the orange wire and see where it lands on the equipment.

The main difference is weather or not your system is using two transformers or if it is a standard system that uses only one transformer. So if the outside A/C unit has its own transformer then you would have a two transformer system. In that case you would use another wire to power the cooling side of the thermostat. I have no idea if the orange wire you have is for that purpose or not since once again you did not tell me where the orange wire was landed on the original thermostat.
Below you will see in the file that the orange wire is usually used in a heat pump system for the reversing valve.

I read the Honeywell manual.
You did not tell me where the wires were placed on the old thermostat so I have no idea what orange is actually used for.
The color code is not always followed and without the knowledge of where the wires were connected to the old thermostat makes being accurate impossible.
I need to know what the orange wire was connected to on the old thermostat or you will need to track down the orange wire and see where it lands on the equipment.

The main difference is weather or not your system is using two transformers or if it is a standard system that uses only one transformer. So if the outside A/C unit has its own transformer then you would have a two transformer system. In that case you would use another wire to power the cooling side of the thermostat. I have no idea if the orange wire you have is for that purpose or not since once again you did not tell me where the orange wire was landed on the original thermostat.
Below you will see in the file that the orange wire is usually used in a heat pump system for the reversing valve.

Excellent question... the orange wire was connected to the "O" screw on the old thermostat. As I follow the metal layout on the old thermostat it ends up on "cool" where the lever would be switched to put the AC on. I hope this is of some help to you. Is there any information on the furnace itself that I can supply you with that might be of assistance? Thank you again for all of the time you've spent working on my problem.

I hope you still have the old thermostat. Please post the complete model number from the old thermostat and the sub base it was mounted on. I will need to look it up in my old Honeywell books to see exactly what you started with.

I hope you still have the old thermostat. Please post the complete model number from the old thermostat and the sub base it was mounted on. I will need to look it up in my old Honeywell books to see exactly what you started with.

I do have the original themostat, but there does not appear to be a model number. Where would this be placed? There are two number on the inside of the wall mounted unit where the wires connect. THe numbers are: Q539A1014 and 9643. I hope this is of some help to you. Thank you.

The 9643 looks like a date code: Mfr's in the 43'rd week of 1996.

Sounds like you have a dual fuel system (heatpump with gas furnace back up). Your problem may not be the thermostat inside, it may be the thermostat out side on the heat pump that tells the system when to lock the heat pump out and use the furnace. The switch may be stuck open keeping the heat pump from working in heat or A/C. You will need a jumper wire from RH to RC at the thermostat.

Here is a copy of the subbase diagram.

http://customer.honeywell.com/techlit/pdf/PackedLit/69-0537.pdf

As mentioned before by T-Top you may have a heat pump. And as I said before try to jump RH and RC together and see if it works.

I seen the mentioning of the heat pump and RC,Rh jumper, just trying to agree with that part. I did not see the part if that person has a dual fuel system that the outside thermostat may have it locked out.

Hey T-Top have you ever noticed that some posters use different names trying to give info or play some type of a game. It took me awhile to figure out on this board how to get the I.P address of the posters. A persons I.P. address on the computer they use stays the same no matter what name a supposed new member signs in on to post. Some posters have 3 or more names they post under. I find that kind of funny.

I suppose that only Experts can obtain IP addreses of posters. I could be wrong because some boards post it or post part of it and some just say "ip logged".

An IP address that the board sees generally changes periodically for people using DSL or cable modems. How often, it depends on a the service provider.

Over my head I'm a hvac tech not a PC tech. I hate to think I was trying to help some one only to find out it's a joke. It's the ASK ME help site and the people in need that get hurt not the techs trying to help.

Over my head I'm a hvac tech not a pc tech. I hate to think I was trying to help some one only to find out its a joke. Its the ASK ME help site and the people in need that get hurt not the techs trying to help.

I agree but I am sure you have read some of the posts and wonder what credentials the supposed helper has. I guess it is a very imperfect world we live in.LOL