sunvic programmer fitting

[wesd]

Hi,

I've got an intermittent problem with my CH where, at the end of a program, the controller seems to close the 2 motorised valves but leaves the pump and boiler running. Normally the boiler, pump and valves all shut off at the same time.

The controller is a sunvic select 207 (12 years old) and , since I'm not a diy'er or electrically qualified, I'm thinking of swapping the controller for a sunvic select 207 xls which I assume is just a newer version.

My question is - will the 207xls physically fit directly onto the existing 207 backplate and do the two controllers use the identical wiring setup?

 

[flameport]

Both of those appear to be standard 2 channel controllers, so to answer the question - yes, it most likely will fit on the same backplate.

However this will not fix the problem.
The fault isn't the programmer, it's one or both of the switches in the motorised valves sticking on.

 

[wesd]

The fault isn't the programmer, it's one or both of the switches in the motorised valves sticking on.

If its the valves that are faulty I would have thought that the boiler and pump would still get switched off at the end of a program?

Of course, I dont know how all the bits fit together and I suppose an intermittent fault seems more likely to be mechanical valves rather than an electronic controller.

 

[ianmcd]

what is the make and model of your boiler it may have a pump over run facility built in

 

[wesd]

It's a baxi barcelona. Hasn't a great reputation but incredibly efficient - heating a 3-bed detached house plus all gas cooking costs £320 a year.

Just noticed tonight that the pipe leaving the HW valve was very hot just after the CH went off even though the HW had been off for almost 2 houirs so maybe the HW valve isn't closing properly? Not as hot as the CH pipe but still a LOT hotter than I would have expected.

The first few times my problem occurred was during the summer when only the HW was running - now it can occur when the CH switches off (the HW being alrady off).

 

[flameport]

If its the valves that are faulty I would have thought that the boiler and pump would still get switched off at the end of a program?

Assuming it has been wired correctly, the programmer only controls the valve motors via the room thermostat or cylinder thermostat.

The actual boiler switching is done via a switch inside the valve, so that the boiler only switches on once the motor has opened the valve.

The switch in the valve has a permanent live, so if the valve sticks open or the switch fails, the boiler will run all the time, even if the programmer and thermostats are off.