Go turn off the boiler manually ,when target temp is satisfied at 20 degrees.Then time how long the stat stays at that temp before it starts to drop ,and report back.
Your last post indicated that when boiler is switched off manually ,thermometers stayed at 20 degrees for several hours , does the thermostat stay at 20 as well ?
Winston I, have said numerous times that if I turn the boiler of completely the temprature remains steady for a long time. Maybe 7 hours on three thermometers.
Your either looking at the wrong display ,or the stat is kaput .
Or the boiler is getting a demand from elsewhere ,can't be bothered to re read all your posts ,is it a combi boiler ?
It would keep firing up every so often even if it's at 18 degrees what ever temp I set it at once it reaches that temp it stays steady for hours. Even if I turn boiler off. So there for when on, it does not need to fire up all the time but it does.
Ok, so there's no hysteresis adjustment or anti-cycling feature on that, which is a bit rubbish. Is the Modulating Control set to on or off? Is the outdoor sensor function definitely disabled?
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