S-Plan central heating - bypass microswitch?

[PedroKTFC]

I have Drayton motorised valves for my central Heating and hot water in an S Plan configuration. However, I have had several failures of the microswitches in these valve where they've not switched off and so left the pump and boiler running. This leads to the boiler over heating and so tripping and needing to be reset (imagine if it didn't trip??!!).

So I was wondering of I could bypass these and switch on the pump and boiler directly when the timer/thermostat call for heat? I really don't see any benefit in going via these microswitches.

 

[mainline]

I have Drayton motorised valves for my central Heating and hot water in an S Plan configuration. However, I have had several failures of the microswitches in these valve where they've not switched off and so left the pump and boiler running. This leads to the boiler over heating and so tripping and needing to be reset (imagine if it didn't trip??!!).

So I was wondering of I could bypass these and switch on the pump and boiler directly when the timer/thermostat call for heat? I really don't see any benefit in going via these microswitches.

What about the situation where the valve fails to open. ?

The boiler shouldn't overheat and cause a trip, it should simply shut down either via room stat, immersion stat or internal boiler stat.

 

[PedroKTFC]

What about the situation where the valve fails to open. ?

The boiler shouldn't overheat and cause a trip, it should simply shut down either via room stat, immersion stat or internal boiler stat.

But what's the difference between that and the valve closing but the microswitch not switching off?

The boiler does overheat: the valve closes but the microswitch fails, meaning the pump and boiler continue to run, water doesn't circulate but the boiler is burning gas until it overheats and trips. At this point the boiler no longer fires and the pump runs forever against a closed valve. Bonkers!