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Comfort Specialist
Comfort Specialist, HVAC Technician
Category: HVAC
Satisfied Customers: 1368
Experience:  Master Lic. holder for HVAC & Gas, Contractor, Estimator, Designer, Air Balance Certified, LG Master Commissioner, UNC Cert. holder for Industrial Ventilation
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Had a builder grade electric thermostat that went bad. The

This answer was rated:

Had a builder grade electric thermostat that went bad.
The system uses Red wire RH RH and RC jumpered
Green Yellow White all marked as such and connected to same
Then there is a left over wire marked C
Was told not to use blue "C" wire
AC does not turn on

Unit controls a two zone system

This is the unit I am installing

Honeywell 5-2 Day Programmable Thermostat with Backlight
Model # XXXXX

Wvfan79 :

Hello there! I'm Norman but you can call me Norm. Let's see what I can do to get you some answers today. I'm ready to get started whenever you are.

Wvfan79 :

Hope you are doing well today.

Wvfan79 :

First off, make sure the old C wire is capped off and not able to bump anything in the wall or on the thermostat.

Wvfan79 :

Did you turn off the main power to the system at the electrical panel before you disconnected any wires or reconnected the new thermostat?

Customer:

it is

Wvfan79 :

Ok, it's capped. Did you kill power before you began?

Customer:

yep

Wvfan79 :

So you shut off two breakers in the panel. One for AHU and one for Outdoor unit?

Wvfan79 :

I say AHU, should have said furnace and outdoor unit.

Customer:

yes i shut both units off

Wvfan79 :

With the thermostat mounted do you get a blower running with the fan switch set to ON?

Customer:

yep

Wvfan79 :

Good deal.

Customer:

bad unit?

Wvfan79 :

Ok press and hold the up button and the fan button together until the screen changes.

Wvfan79 :

On the left you should see a function #1, what does the number on the right of the screen say?

Customer:

loose wire all good.

Wvfan79 :

Lets verify your thermostat setup too. This is a common missed step.

Customer:

ok

Wvfan79 :

This is where we choose the system type and manual/auto changeover

Wvfan79 :

Press both up and fan and hold them both until the screen changes.

Customer:

ok

Wvfan79 :

Make sure Function #1 is set to 0 on the right

Wvfan79 :

Press next until you get to function #12

Customer:

0

Wvfan79 :

Would you like your thermostat to change over from heating to cooling on it's own based on your setpoints or would you like to have to manually change the thermostat from heat to cool?

Customer:

does not go to 12

Customer:

manual

Wvfan79 :

Ah, you have the D model. Not a feature on this one. You've got it set-up right. It will be manual change over as it is now.

Wvfan79 :

Have you tried both A/C and HEAT?

Wvfan79 :

If not, press DONE and try them while I stand by.

Customer:

yep

Wvfan79 :

Make sure the furnace doors are on if not already so.

Customer:

done

Wvfan79 :

That's great. Did you have any other questions for me today?

Customer:

nope

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