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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I bought a new digital thermostat to help my furnace/air

Customer Question

I bought a new digital thermostat to help my furnace/air cond. be more efficient. I hooked it up last weekend but I don't think I have it connected right. Right now I have it set at 74 and it's 79 in our house and the air is blowing but it's not super cold like it was before. I have a honeywell thermostat attached right now. Is this something i can use or what should I do?
Submitted: 1 year ago.
Category: HVAC
Expert:  Tim H. replied 1 year ago.

Let me know if you have additional questions. Otherwise, good luck! Thanks for using Just Answer and please don't forget to rate my service as that's how experts get paid (thanks in advance for any bonus left). Otherwise experts work at their own time and expense. Feel free to post back with any more questions. Remember, you can rate question at any point and still ask more questions (related to the same thing) later on. Experts prefer if you rate question at the end of our first chat.

What kind of system do you have? A heat pump or standard central AC?

Customer: replied 1 year ago.
Im guessing heat pump since the air and heat go through the same unit, but I don't know for sure
Expert:  Tim H. replied 1 year ago.

I'd have to know that before I can help you with wiring.

Customer: replied 1 year ago.
Where would I find that info?
Expert:  Tim H. replied 1 year ago.

Whats the make and model of outside unit?

Customer: replied 1 year ago.
It says lennox total comfort system
Expert:  Tim H. replied 1 year ago.

That doesn't help. Need you to find a tag on outside unit and give me full model number.

Customer: replied 1 year ago.
HS29-261-1P
Expert:  Tim H. replied 1 year ago.

Looks like a standard central AC. Your wiring seems to look OK. You don't need the blue on O

Expert:  Tim H. replied 1 year ago.

Your unit could be low on charge.

Customer: replied 1 year ago.
What does that mean? And how do I fix that?
Expert:  Tim H. replied 1 year ago.

When is the last time unit was serviced?

Customer: replied 1 year ago.
Hasn't been since we've owned this house. The only thing is it was working perfectly fine with the old thermostat. I changed it out in the hopes of saving money on efficiency and the old thermostat had mercury in it, which I didn't like the idea of.
Expert:  Tim H. replied 1 year ago.

Your unit could be low on charge (refrigerant). Then it would cool somewhat, but not as good as it once did.

Customer: replied 1 year ago.
Why would it have been working fine before I changed the thermostat though?
Expert:  Tim H. replied 1 year ago.

Is the outside unit running?

Customer: replied 1 year ago.
Not right now, but it had been last week.
Customer: replied 1 year ago.
I am worried that I haven't wired everything correctly and if that was why it wasn't working right.
Expert:  Tim H. replied 1 year ago.

The wiring looks OK. Green to G, red to RC-RH, white to W, and either yellow or blue to Y depending on which color is on Y down at the furnace.

Customer: replied 1 year ago.
I have both the blue and yellow connected to different spots. That would matter would it?
Expert:  Tim H. replied 1 year ago.

You only need one on Y. The "O' doesn't come into play on a standard central AC.

Customer: replied 1 year ago.
Would the blue be for the heat then?
Expert:  Tim H. replied 1 year ago.

Go down to furnace, find where the thermostat wiring comes into the board. See which color is on Y

Expert:  Tim H. replied 1 year ago.

Did you have additional questions on this?