How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Phil Your Own Question
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
Type Your HVAC Question Here...
Phil is online now
A new question is answered every 9 seconds

I have a hot water heat system with four zones. One zone has

Customer Question

I have a hot water heat system with four zones. One zone has started to malfunction by coming on but not shutting off. I have installed a new thermostat and a new zone control valve but it still keeps heating. Why?
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: Yes, I can turn the thermostat control to off and it indicates no heat, but the zone valve does not turn off unless I turn the manual control on the valve itself.
JA: Do you plan on doing the work yourself?
Customer: Yes
JA: Anything else we should know to help you best?
Customer: Since this is a hot water system there are no filters. All the zone valves are interconnected so I was wondering if the thermostat control sends the on signal to turn the valve on but somehow does not get the signal to turn off?
Submitted: 9 months ago.
Category: HVAC
Expert:  Paul the Plumber replied 9 months ago.


My name is***** should be able to help on your boiler zone. Does your system have swing checks in it? They can sometimes get stuck open and leak heat by when you don't want it. That is where I would look first.

Customer: replied 9 months ago.
I installed the original system and do not believe it has swing checks. I am now looking at the possibility of the 24V switch relay failing?
Expert:  Paul the Plumber replied 9 months ago.

Sorry it has been a bit to answer. When you say you changed the zone valve are you saying that you changed the whole thing or just the head?

Expert:  Paul the Plumber replied 9 months ago.

What kind of zone valves are they