What is the function of terminals R, Rc, O, B, G, W, and Y on a Honeywell CT 87N thermostat?

You did not say what model you had. Here is a page I found for Honeywell. Next time you look up manuals, try typing in pdf instead of the word manual.

http://www.honeywellcleanair.com/air-purifiers/customer-support/owner-manuals/

Where is the thermostat in relation to the return? Is there air flow or is the air stagnant in the area of the thermostat. Have you placed a thermometer in varios locations where the thermostat is located? Try these locations and see if the thermostat needs to be placed in a location better able to reflect room temperature. Also how long have you lived in the house? If it is a newer home I suggest that you contact the builder or the air conditioner/heater installer to see if they have a schematic of the placement of the thermostats.

Hello, this is Ava with Think Crucial.

You may check to make sure that the power cord is correctly connected to the outlet. Test the outlet is functioning properly using another appliance or lamp. Also, check the fuse or circuit breaker. The outlet may be overloaded if other appliances are also in use. Establish and correct the cause of the overload. If none of these works, then there is something wrong with your purifier unit and contact the store where you purchase it or Honeywell for replacement. It is advised not attempt to repair the unit yourself.

You can purchase a wide variety of high-quality Honeywell replacement parts for your Honeywell air purifier direct from Think Crucial with free shipping and an exclusive 10% coupon for Fixya.com readers, use code: FIXYA10

https://www.thinkcrucial.com/search?type=product&q=honeywell

I hope this was helpful.

Ava B.
Think Crucial Customer Care
http://www.thinkcrucial.com/

Might be dust in the thermostat. Filters might be dirty. I would call a service man before the house burns down!

Hello, this is Ava with Think Crucial.

You may check to make sure that the power cord is correctly connected to the outlet. Test the outlet is functioning properly using another appliance or lamp. Also, check the fuse or circuit breaker. The outlet may be overloaded if other appliances are also in use. Establish and correct the cause of the overload. If none of these works, then there is something wrong with your purifier unit and contact the store where you purchase it or Honeywell for replacement. It is advised not attempt to repair the unit yourself.

You can purchase a wide variety of high-quality Honeywell replacement parts for your Honeywell air purifier direct from Think Crucial with free shipping and an exclusive 10% coupon for Fixya.com readers, use code: FIXYA10

https://www.thinkcrucial.com/search?type=product&q=honeywell

I hope this was helpful.

Ava B.
Think Crucial Customer Care
http://www.thinkcrucial.com/

If it was wired to the return air it will have a flag switch to let it know the blower is on, sometimes the flag comes off and it wont operate, sometimes it is wired directly to the computer board on terminals EAC that stands for electronic air cleaner and the board turns the air cleaner on when the blower is running, if you have a meter you can check voltage in both places to see which one is the problem. let me know. thanks wally

HONEYWELL WEBSITE:
Go to honeywell.com
Under red welcome sign
Bottom red highlighted box literature/image search
Type in thermostat model number
Click on arrow to right
Then click on the PDF files owners manual / installation instructions
If you can’t find what you want, the bottom left and bottom of web
Page, they have homeowners assistance and Home products to get the help you need.

Go to honeywell.com
Under red welcome sign
Bottom red highlighted box literature/image search
Type in thermostat model number
Click on arrow to right
Then click on the PDF files owners manual / installation instructions
If you can’t find what you want, the bottom left and bottom of web
Page, they have homeowners assistance and Home products to get the help you need.

Hi, If indeed you do have a heat pump, there wouldn't be any gas involved as a heat pump runs on freon with a reversing valve and heat strips for aux and emerg. heat. For gas electric operation thermostat terminals are rc to rh with factory jumper. Red wire to either.W to W for Heat, Y to Y for cooling G to G for Fan. If you have a blue, you wont need it unless this is a commercial stat useing a common for the Led lights on the stat. The unit will get its 24volts through R terminal in combination with y,w,and,g. Cant be a heat-pump if you have a gas furnace.Wrong t-stat. You need a gas /elect stat. And on a 24volt programmable t-stat, the batterys are used for the program only.If the batterys die, than you will loose the program on most residential stats. On commercial stats with the common in play, when batters die the stat defaults back to the factory settings.If you had a Lennox heat-pump stat on a gas/elect unit, you need to change it. Someone was using what they had on hand. Let me know if this has helped you.I will be here if you need me. Sincerely,
Shastalaker7