Hot water thermostat opens/shuts valve, but no pump

[Agile]

Nothing is over riding the clock.

That is just a device to give the boiler a call for heat.

Frost protection would still work if you threw away the timeclock.

Ins integral to the boiler design.

Tony

 

[abenn]

OK, thanks, I suppose you're saying that all UK gas central heating systems work that way, which is what I was asking.

 

[Agile]

Its the traditional way.

But many are wrongly wired or have long term faults!

Tony