Medium
9F on Viessmann Vitodens 242-F B2UA

Your boiler has lost communication with the solar heating control unit, meaning your solar panels won't be helping to heat your water right now.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Solar control module fault

From this model's manual
Verified against the Viessmann Vitodens 242 F B2ua installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Turn the boiler power switch off and back on again to attempt a system resetCheck if any electrical breakers for the solar thermal system have tripped in your fuse boxEnsure no external wiring to the solar pump station has been accidentally unplugged or damaged

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