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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Honeywell VisionPro IAQ thermostat won't run AC. I moved

Customer Question

Honeywell VisionPro IAQ thermostat won't run AC. I moved this thermostat from another location in the house because the left side of the touchpad wouldn't respond. I can get the AC to run in "test" mode, but that only lasts about 5 minutes. I have 2 air handlers next to each other, and it looks like they are both being controlled by the same Honeywell panel. The other air handler is operating fine.
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, if half of the thermostat touch pad does not work, the thermostat is most likely bad.

If two thermostats operate the system though one central control box, thats called a two zone system... it can get complex.

If you had an **exact* replacement for that thermostat and program it correctly that would most likely effect the repair... it its not exact there can be complications.

Tell me a lot about your technical skill sets and I can coach for half an hour on the diagnosis and repair.

I will be out to lunch now for 30 minutes or so and pick up your response when I return.

Customer: replied 1 year ago.
I have an MS in chemical engineering, so while not familiar with HVAC systems in detail, I can manage to figure out most things. I know that the original touch pad is faulty and needs to be replaced. I only mentioned it to explain why I'm trying to use other thermostats from around the house. I have 4 other identical thermostats. I'm going to reset the thermostat I'm using to factory settings. I didn't notice any settings on the thermostats that would make any difference to the control panel other than the zone designation, which I've played around with as well. The other thing I'm going to attempt is to kill the power to the control panel to attempt to reboot it. When I switch off the air handlers, the control panel stays powered. Were you able to see the list of things that I've already tried?
Sorry, I'm pretty stressed about this. I have house guests arriving shortly and, of course, this is the zone for the bedrooms!
Customer: replied 1 year ago.
The only other thing I can think to mention is that I replaced the back plate to correspond to the thermostat I'm using. The thermostat is still not operating in the same way, so I'm pretty sure I got the wires secured correctly. The only thing that's strange, though, is that when I switch off the power to the air handler, the thermostat goes blank -- this doesn't happen at the other thermostat locations. Also, there are no error messages showing on the touchpad. When I switch to cooling mode, the thermostat either stays in "wait" mode or goes from "wait" to off (showing no mode).
I'm currently reading the manual for the W8835 EnviraZone Panel, and there is a reboot button. I just want to be certain that it won't clear any settings.
Customer: replied 1 year ago.
I solved it! I reset the thermostat to factory settings and now, finally, it displays "cooling on".
Expert:  Phil replied 1 year ago.

Good work!!

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