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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I replaced a 2-zone control board within my house.

Customer Question

I replaced a 2-zone control board within my house. I have a carrier heat pump from the mid -90's. a thermostat upstairs and downstairs. When I rehooked the board, the downstairs only turns on the heat. The upstairs only turns on AC. I took photos of the wiring in the thermostats as well as the control board. Is there a way to upload these?
Submitted: 2 years ago.
Category: HVAC
Expert:  Phil replied 2 years ago.
Welcome! Your question will be answered in detail. UP to 48 hours step by step coaching on diagnosis & repairs $38 additional.
Use the 'attach files' link at the bottom left of your reply box.
Sorting things like this out can take hours. I will submit an 'additional services' offer if I am not able to coach you to a solution in 30 minutes.
We can go from there if you wish.
Customer: replied 2 years ago.
thanks. the thermostat photos are showing 2 different thermostats.
Expert:  Phil replied 2 years ago.
Hello again, its a real long shot from here without a wiring diagram, there may be one under the zone controllers main section...I need the full model number of the zone controller 48s did not search in my files.
IF you find that, and get me some close up photo's that are well focused enough to read the letters on the terminal blocks, and if you are somewhat skilled with a multi meter, I can stay with you on this.
Let me know what you can find, we can go from there.
Customer: replied 2 years ago.
Thanks for taking a look, Phil. It took me a while to get back. hopefully you can see the wiring with these pics. One thermostat just does heat. The other will only do cold. Neither will do auto. They both will shut the unit off when the correct temp is reached, however. I thought I put all the wires back correctly on the zone board, but I think this is where the mixup is. I never switched any wires on the thermostats.
Expert:  Phil replied 2 years ago.
Thanks for the photos,
This is going to take a very much experience zone controls tech (generally working for a well established company) to come the the job site with test equipment and sort it out that way.
I will opt so that others here can see your question, however it is a one a hundred long shot that anyone will volunteer to get involved.
Customer: replied 2 years ago.
Thanks for the reply.

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