Viessmann boiler error 4B
The error code 4B is caused by a lack of electrical power from the circuit board. You can try to remove the power cable and then put it back in. Please refer to the user manual for instructions.
4B error code is often caused by a lack of electrical power from the circuit board. One way to deal with this is to unplug your boiler for about 5 minutes and plug it back in afterward. You can also try opening up the circuit breaker panel and checking if you have any loose wiring or blown fuses that could be causing problems with your boiler.
An error code 4B in a viessmann boiler can mean low water pressure or too much pressure in the pipes leading into or out of the boiler. This can be caused by a clogged water line or valves that are not fully open. There are also other causes for this error, but these usually don’t happen as often and typically affect newer viessmann boilers only.
A quick fix for this problem can be to turn off the power at your home’s breaker box, wait 10 minutes, then turn it back on again. If that doesn’t work, you should contact a plumber specializing in commercial plumbing systems as soon as possible.
Error 4B is a fault code that indicates that the indoor temperature is too high.
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