Hi folks, I have been trying to suss my system fault: I have inherited a conventional old-school vented gas system with 2 zone valves, on for CH one for HW, a thermostat for each service and an old-school programmer.
If I only switch the CH on, and the HW off at the programmer, the CH rads heat up as normal.
If I simultaneously, or later on; switch on the HW at the programmer, (leaving the CH on), the CH rads all go cold. They stay cold even if I then switch the HW off again at the programmer, or turn the tank stat down.
Both CH and HW zone valves are working and moving in response to the programmer and thermostat settings.
So if the HW is or has been on at all, the CH rads do not heat up - even 2 hours after I have reverted to CH only.
After extensive testing, including checking all the wiring and confirming with a multimeter, and viewing the zone valve heads moving, I am a bit stumped. (I am an engineer, so I understand how the system works and what each component does).
Could this be a duff HW valve internally - i.e. not the electric motor head, (which I can see working), but the actual valve element inside the brass housing failing and allowing water to leak past?
Thanks in advance.
If I only switch the CH on, and the HW off at the programmer, the CH rads heat up as normal.
If I simultaneously, or later on; switch on the HW at the programmer, (leaving the CH on), the CH rads all go cold. They stay cold even if I then switch the HW off again at the programmer, or turn the tank stat down.
Both CH and HW zone valves are working and moving in response to the programmer and thermostat settings.
So if the HW is or has been on at all, the CH rads do not heat up - even 2 hours after I have reverted to CH only.
After extensive testing, including checking all the wiring and confirming with a multimeter, and viewing the zone valve heads moving, I am a bit stumped. (I am an engineer, so I understand how the system works and what each component does).
Could this be a duff HW valve internally - i.e. not the electric motor head, (which I can see working), but the actual valve element inside the brass housing failing and allowing water to leak past?
Thanks in advance.