S Plan Help

[BABYCAKES]

Hi there,

I have a system boiler set up as S-Plan, with two 2-port motorised valves.

If I move the lever for the CH motorised valve to the open position, should the boiler fire up even if the programmer has the CH off?

 

[terryplumb]

No

 

[BABYCAKES]

Thanks terryplumb,

If the microswitch was stuck on, would that cause the boiler to fire up?
The reason I ask is that my boiler and CH is on permanently even with the programmer turned off. A few days ago, I noticed that the CH was coming on with the HW, and I suspected the motorised valve was playing up, and now the boiler is on all the time and the radiators are hot.

 

[terryplumb]

Yes ,the microswitches ( when closed by the motor) energise the boiler,and if stuck closed the boiler will fire continuously , irrespective of the timer / programmer settings.

 

[BABYCAKES]

Yes ,the microswitches ( when closed by the motor) energise the boiler,and if stuck closed the boiler will fire continuously , irrespective of the timer / programmer settings.

okay. so last question, do the microswitches only close if the motor opens the valve? Does the manual lever setting on the motorised valve not have the same effect?

 

[terryplumb]

Correct. All the manual lever does is open the mechanical part that allows water to flow through the pipes,it does not fire up the boiler.

 

[BABYCAKES]

thank you.

 

[Johnmdc]

It depends on what make the valve is.
Honeywell and Drayton don't, but Danfoss valves do.

 

[ianmcd]

okay. so last question, do the microswitches only close if the motor opens the valve? Does the manual lever setting on the motorised valve not have the same effect?

The manual lever is for filling the system with water, you dont want the boiler and pump running as you are filling the system with water , hence why the end switch doesnt make when set to manual