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e2fireman 06-28-2008 11:00 AM

thermostat issue?
Hey all...

My digital thermostat was installed in the winter and everything appeared to be working fine until the weather warmed up. The heat side works fine but when set to cool it blows warm air. I would think its a wire in the T stat that needs to be switched, but... I'm not sure where to look for solution.

HvacWiz 06-28-2008 12:12 PM

Is there a jumper on the stat between the R-RC terminals ?

e2fireman 06-28-2008 01:10 PM

hey wiz... thanks for the fast reply!! :)

Yes, there is a jumper

geo fan 06-28-2008 06:16 PM

is it working now
i couldnt tell from your response

e2fireman 06-28-2008 06:35 PM

No I wasn't sure what to do wirh it. I took the jumper out and tried to run the sytem but that made everything quitworking, so I left it until I heard from you again

geo fan 06-28-2008 08:00 PM

if you have oil heat
probubly should be out if not leave it in . what is connected to the y terminal

micromind 06-29-2008 12:28 AM

If it's a split system (condenser unit outside, furnace inside), make sure the outside unit has power to it. Also, check the control wire (usually a thermostat wire) between the inside unit and the outside one.

If these check out OK, let us know, and we'll lead you through a few more steps.


e2fireman 06-29-2008 09:04 AM

Okay, guys, thanks for all the helpful comments and suggestions, and I'm sorry I wasnt more descriptive of the problem. It is an oil furnace with an outside heat pump unit. The heat pump works and will turn on when i set the system to cool and adjust the temp below what the stat reads. The problem is that it is blowing warm air. The system worked fine until I upgraded to a digital stat. Thinking the stat was bad, I replaced it, but the problem persists!

Hope this helps.

geo fan 06-29-2008 10:55 AM

is it a heat pump
a heat pump will have an O terminal this needs to be energized for the heat pump to be in ac mode. sounds like you need a heat pump thermostat with a dual fuel control board at the furnace. a quick fix would be to get the 24 volt wire at the condenser and wire the y and o to the 24 volt incomeing wire this will energize the reversing valve and sould turn on the ac but to stage the equip properly will require a pro and maybe a different thermostat . turn the power off before open the condenser up and post back if it works

8 Ball 06-29-2008 11:33 AM

If the problem existed before you changed the stat, the thermostat may not be the culprit. Your heat pump may need refrigerant, or the changeover solonoid may be defective.

Lets also make sure it truly is a heat pump. Can you post a picture of the outdoor unit? Just seems unusual to have an oil fired furnace/heat pump setup.

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