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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Ran new tstat wire had lights on board. Turned tstat on

Customer Question

Ran new tstat wire had lights on board. Turned tstat on nothing. Now no lights unhook red wire still nothing tformer still good fuse good
Submitted: 2 years ago.
Category: HVAC
Expert:  BillyHvac replied 2 years ago.
is fuse blown
Customer: replied 2 years ago.
No
Expert:  BillyHvac replied 2 years ago.
Is transformer still ok?
Customer: replied 2 years ago.
Could it be wire to outside unit
Expert:  BillyHvac replied 2 years ago.
That is commonly where the damage is...the outdoor wire or contactor...
Customer: replied 2 years ago.
Transformer bench test ok
Expert:  BillyHvac replied 2 years ago.
If transformer is good and fuse is good but no light on board or thermostat power...it would be a bad board...
Customer: replied 2 years ago.
Unhooked the outside wire. No 24 volt on board
Expert:  BillyHvac replied 2 years ago.
no power R to C?
Customer: replied 2 years ago.
I had lights on board until I turned on tstat. Tstat works other unit in house
Customer: replied 2 years ago.
I'll check
Expert:  BillyHvac replied 2 years ago.
did it blow right away...or after turning to cool
Customer: replied 2 years ago.
Right away. Nothing r to c
Expert:  BillyHvac replied 2 years ago.
if fuse is still good and transformer is good then board is bad
Customer: replied 2 years ago.
OK thanks
Expert:  BillyHvac replied 2 years ago.
let me know if any other info pops up.
Customer: replied 2 years ago.
Ok
Customer: replied 1 year ago.
The same problem with the new board. I do however have 25 volts on the neutral with the door switch open

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