My house was built 1972 and I've had a series of problems with the actuators on the zone valves in my heating system. In the past heating engineers have replaced the (motor-on motor-off) actuators with Sunvic SM5203s which have only lasted about 5 years before they needed replacing again (Ive just seen suggestions not to tighten the screws so they last longer!)
Now the valve body on the HW circuit has started to seep around the pin - and this has probably led once again to the actuator failing - it continuously clicks. I have for a while suspected that the inside of the valve may not be working properly as the water is getting very hot, even though I believe the HW thermostat was switching off. The valve itself used to make a clunk-clunk as it turned but no longer does this - there was a small resistance to it rotating, but now it rotates freely. Is it possible that the insides of the valve could have failed so that its always open?
Ive attached pictures of the valve, plate and actuator.
I'd be thinking of replacing the valve body as well as the head but the current Sunvic EML3454 valve body appears to be very different from mine - see the attached pictures. You can see that the nuts screw inside the valve body where the EML3454 fits differently and appears to be rather longer - as you can see theres not really any space for a longer valve body. So does anyone recognise my present valve as an old Satchwell product? Is there a service kit to repair its insides and the seal? Is there a replacement valve that would fit without too much alteration to the plumbing? If it helps, the only marking I can see on the valve body is "FC" in the top left corner of the plate
And just to add another complication, I've no idea whether my pipework is 22mm or 3/4".
I have an opportunity coming up for getting the valve repaired or replaced while my central heating is drained to allow my bathroom to be renovated - I'm not a plumber but I could get the bathroom fitter to do this if I can find the right bits.
Now the valve body on the HW circuit has started to seep around the pin - and this has probably led once again to the actuator failing - it continuously clicks. I have for a while suspected that the inside of the valve may not be working properly as the water is getting very hot, even though I believe the HW thermostat was switching off. The valve itself used to make a clunk-clunk as it turned but no longer does this - there was a small resistance to it rotating, but now it rotates freely. Is it possible that the insides of the valve could have failed so that its always open?
Ive attached pictures of the valve, plate and actuator.
I'd be thinking of replacing the valve body as well as the head but the current Sunvic EML3454 valve body appears to be very different from mine - see the attached pictures. You can see that the nuts screw inside the valve body where the EML3454 fits differently and appears to be rather longer - as you can see theres not really any space for a longer valve body. So does anyone recognise my present valve as an old Satchwell product? Is there a service kit to repair its insides and the seal? Is there a replacement valve that would fit without too much alteration to the plumbing? If it helps, the only marking I can see on the valve body is "FC" in the top left corner of the plate
And just to add another complication, I've no idea whether my pipework is 22mm or 3/4".
I have an opportunity coming up for getting the valve repaired or replaced while my central heating is drained to allow my bathroom to be renovated - I'm not a plumber but I could get the bathroom fitter to do this if I can find the right bits.
