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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have Hunter 44260 thermostats in a house with hot water

Customer Question

I have Hunter 44260 thermostats in a house with hot water heat running 3 zones. I have this thermostat in all locations. The problem is the thermostat will engage the boiler at the low set point but will not shut off once the desired temperature is reached. This is a 2-wire system with Red (+24V) and White (Common).
Submitted: 1 year ago.
Category: HVAC
Expert:  Rick replied 1 year ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

What do you have for a boiler? brand and model please? Do you have zone valves (brand?)? or a pump for each zone?

Customer: replied 1 year ago.
Weil-McLain Gold CGa-4 Boiler, standing pilot with Honeywell gas valve. Single circulation pump at return side of boiler with Honeywell zone valves.
Expert:  Rick replied 1 year ago.

OK, turn down all the thermostats wait 5 minutes then go to each zone valve and push the lever on the end of the valve head/operator to the right. Note if you feel any resistance in the lever and note which one(s) has the resistance. Then tell me what you found

Customer: replied 1 year ago.
No resistance. All 3 move freely from Auto to Manual position
Expert:  Rick replied 1 year ago.

And all your thermostats are turned down?! No resistance at all? If so disconnect the wiring from each thermostat, 1 at a time, then check each valve in turn as before.

Customer: replied 1 year ago.
when I disconnect the wiring I get resistance at each zone valve.
Expert:  Rick replied 1 year ago.

So that's telling me the problem is with the thermostats but all 3 failing at the same time is really unusual. Did something happen? a power surge? static discharge at the stats?