Viessmann boiler error fault 99

Viessmann boiler error fault 99 results from a series of different factors. When the condensate pipe is blocked, and the boiler is on, it will lead to this error.

A blocked condensate pipe can be caused by a clog or a restriction in the pipe itself. To avoid Viessmann boiler error fault 99 from occurring, it’s best to keep the condensate pipes clear to work properly without any blockage.

The Viessmann boiler fault 99 occurs when a valve on the pressure relief valve activates. It is not dangerous, although it may cause increased noise and steam.

The error code 99 can be triggered by several different faults. Many small components in the water system interact with each other, and many possible failures lead to an error code 99. These include:

– high-pressure switch malfunctioning or failing to activate

– cross-connection between the incoming water line and low-pressure sideline

– air in the low-pressure sideline

– excessively high flow rate in either the hot or cold water lines

This list is not exhaustive, as this fault code has many possible causes.

Error fault 99 is a warning that displays when the boiler fails to ignite.

The error is generated when there are problems with the heating circuit, a power supply, or a safety system.

The following are some of the causes of Error fault 99:

– Power supply or isolation issue

– High water temperature

– Low water temperature

– Faulty heating circuit

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