Hi I have read a lot of similar posts but nothing that quite answers my problem. I have a Vaillant Ecotec Plus 418 it is 6 years old. We keep having had the same/similar problem where the central heating isn’t coming on automatically in the morning and is showing f23 fault. I reset the boiler and it starts up again however the radiators never get properly hot. In contrast the pipes connected to the rads are scalding!! The thermostat is set at 22 but the house never gets above 18. We’ve now tried having the heating is on constant. The boiler keeps coming on for 30 secs-45secs then getting to S7 and stopping.
We have previously had a plumber replace the pump and also the Danfoss automatic switch. But then the same problem comes back. All the rads have been bled. We tested whether it was gunk by taking one off and emptying it. Small amount of black sludge/water. Any ideas?
We have previously had a plumber replace the pump and also the Danfoss automatic switch. But then the same problem comes back. All the rads have been bled. We tested whether it was gunk by taking one off and emptying it. Small amount of black sludge/water. Any ideas?
