I have a Vaillant combi (kitchen) and a danfoss thermo (not n wall, I leave it lying around). Sometimes the boiler does not come on for the heating for a long time (hot water fine).
Eg now it's pretty chilly this morning, the heating is not on. I press up on the Danfoss until it shows 20.5 , and nothing happens. 10 minutes later, still nothing. The Danfoss display still shows 20.5 and has a little flame icon. Pressed up again until it shows 22.5. Nothing happens for about 2 minutes, then it comes on.
It's more noticeable when I come back from a week away on holiday: I can push it to 22.5 and nothing whatsoever happens for at least 24 hours.
Sometimes it's perfectly fine.
Any ideas please?
Eg now it's pretty chilly this morning, the heating is not on. I press up on the Danfoss until it shows 20.5 , and nothing happens. 10 minutes later, still nothing. The Danfoss display still shows 20.5 and has a little flame icon. Pressed up again until it shows 22.5. Nothing happens for about 2 minutes, then it comes on.
It's more noticeable when I come back from a week away on holiday: I can push it to 22.5 and nothing whatsoever happens for at least 24 hours.
Sometimes it's perfectly fine.
Any ideas please?