How to switch my central heating/ AC unit thermostat from AC to heat?

Question

Okay, we installed a thermostat last winter & it heated the house fine. When the summer came, the AC would not blow cold air, it just blew hot air. I called my friends husband & he said the thermostat only works for heat or AC, either one at a time & that he had to "switch" it from heat to AC. After he came over & spend 5 mins. "switching" it over the AC worked perfectly but the heat wouldn't blow hot air, just cool air.. which was fine b/c it was summer time. Now we are back in the winter weather & I dont know how to "switch" from AC to heat. So my friend isn't married to the guy that came over & "fixed" it last time & Im not sure what to do!?! It is a Honeywell Non-programmable thermostat RTH5100B & I guess it only supports either heat or air, one at a time. I did notice that the guy that "fixed" it last time took the face off the thermostat. Does anyone know how I might can try to switch this from cool air to heat? Its going to be a very cold night tonight & it would be nice to be able to be warm in the morning! Thx!!

Additional Details

Okay, took the "face" off the thermostat & I do not see anything that says heat or AC. I do see wires & I will tell u what color they are & where they are connected.
Red wire connected to Rc
Yellow connected to Y
Orange wire connected to W
Green wire connected to G
The blue wire & white wire are not connected to anything & there are 2 outlets with nothing connected to them & they say R & not used.

Answer 1

Best Answer - Chosen by Voters

The lower right button should switch the unit between cool and heat.
I find it interesting that he had the cover off and it took him "five minutes" to get it to cool. It could be he moved the 24 volt feed from heat to cool {RH to RC on your stat}. There should be a jumper wire connecting RC and RH so that you can operate both modes from your stat. It could also be that someone has it hooked up wrong, I obviously can not be sure with out seeing it.
You may want to bite the bullet and give a HVAC company a call
God Luck.

Source(s):

My 20 plus years of repairing and diagnosing problems like yours.

Answer 2

There is switch on the side of the thermostat that reads "COOL OFF HEAT'
Slide the switch to HEAT and set the temperature to 68 and go to bed.. There are 2 temperature readings one for what it is and one for what you want. The one that you set is the one that moves or has a pointer to the setting.

Source(s):

Had one for years.

Answer 3

Here is a installation manual for your thermostat. You should be able to find what you need.

Source(s):

http://customer.honeywell.com/techlit/PD…

Answer 4

Wow! Ok take the cover off the thermostat, you should see 4 different color wires; green, red, white, and blue or yellow. If you do not see these wires and attached to their corresponding locations then it is not wired up correctly and that guy was pulling your leg by only temporarlly fixing the problem. If that thermostat says heat on one side and cool on the other, then it should do exactly that unless there is a problem with your furnace or not wired correctly.

Source(s):

You're right Paranut I forgot about the jumper wire and they did say it was a newly installed stat. MAKE SURE THERES A JUMPER BETWEEN RC AND RH. good one