I have a Vaillant 618 boiler and Unistor cylinder. There are two heating zones, controlled by a VR61, with a VRC470 (installed in October; replaced a VRC430) and a VR81.
Yesterday evening, and also this evening, the boiler has failed to reheat the cylinder after a bath, despite there being a timed demand for DHW.
The boiler status is stuck on S20 ('warmstart demand'), with the fan running and does not progress through to S24 ('burner ignited') as it usually would.
I managed to kick the system out of this status yesterday by doing a factory reset on the VRC470.
This is an entirely new and sudden fault on a system that has been working perfectly. No recent work done.
Any suggestions?
thanks
Jon
Yesterday evening, and also this evening, the boiler has failed to reheat the cylinder after a bath, despite there being a timed demand for DHW.
The boiler status is stuck on S20 ('warmstart demand'), with the fan running and does not progress through to S24 ('burner ignited') as it usually would.
I managed to kick the system out of this status yesterday by doing a factory reset on the VRC470.
This is an entirely new and sudden fault on a system that has been working perfectly. No recent work done.
Any suggestions?
thanks
Jon