I had the EXACT SAME THERMOSTAT fail on 2 boiler systems. I installed that useless over engineered "Honeywell Home CT87K1004 The Round Heat Only Manual Thermostat". Do you know that is has a 3v BUTTON BATTERY in it?! I put it in my Father-in-Law's house where it is connected to a TACO zone valve. It did not work. I did the same procedure as you and tied the Red and White together to make sure the zone worked, and it did. I then bought the Honeywell round thermostat to my house to test it. My thermostats are connected directly to a TACO Zone Valve Control unit (ZVC403). The thermostat failed on that, too. Well the thermostat didn't fail, IT NEVER WORKED. Honeywell needs to do better. I installed a basic no-name electronic thermostat for my Father-in-Law. (I tore apart that Honeywell to get to the non-serviceable battery to test it and yes, it was OK at 3v DC)
@@HometownHVAC Better to test the wiring lines from the thermostat, especially after seeing that inferior "clothesline" wiring job flapping in the wind.
The second you said they jus got a new tstat, I already knew that was the culprit
I had the EXACT SAME THERMOSTAT fail on 2 boiler systems. I installed that useless over engineered "Honeywell Home CT87K1004 The Round Heat Only Manual Thermostat". Do you know that is has a 3v BUTTON BATTERY in it?! I put it in my Father-in-Law's house where it is connected to a TACO zone valve. It did not work. I did the same procedure as you and tied the Red and White together to make sure the zone worked, and it did. I then bought the Honeywell round thermostat to my house to test it. My thermostats are connected directly to a TACO Zone Valve Control unit (ZVC403). The thermostat failed on that, too. Well the thermostat didn't fail, IT NEVER WORKED. Honeywell needs to do better. I installed a basic no-name electronic thermostat for my Father-in-Law. (I tore apart that Honeywell to get to the non-serviceable battery to test it and yes, it was OK at 3v DC)
When you have 29 volts at TT terminals, you known the thermostat circuit is not closed.
@@john7017 Yeah lol Cant believe I let that go over my head, sometimes we gotta get lost in the weeds to learn.
He checked for voltage at ff first hahaha
Great job. could you have jumped it down stairs to confirm or lead to bad thermostat?
@@petergriffin1546 Yes I could have jumped it out downstairs at the Furnace. Just done it at the thermostat out of habit.
@@HometownHVAC Better to test the wiring lines from the thermostat, especially after seeing that inferior "clothesline" wiring job flapping in the wind.