Viessmann boiler error 35
The boiler must be shut off for a certain amount of time before restarting.
Viessmann boiler error 35 occurs when the water is not hot enough. The problem can be fixed by increasing the temperature and/or adding more fuel to the fire.
This error code typically corresponds to some reasons:
– water temperature is too low (or might need time to heat up); – burner output is too low due to poor ventilation, clogged chimney, or blocked inlet; – the insufficiently high water level in tank; – boiler standing time is too short (causes a sudden increase in the gas demand).
The error 35 means a clogged condensate drain. A blockage in the condensate line usually causes this. The user manual suggests:
– Unclogging the condensate drain by removing and cleaning it with hot water, or
– Repointing the drain line to a new location will be easier on the user if there is no access to cleaning.
“Inspections, Installations, Repairs & Maintenance”
