BoilerFaultCodesTechnical description
Communication fault: Solar control module or extension module
What causes this fault?
This fault occurs when the boiler's main computer loses its digital connection with the supplementary units that manage your solar thermal panels or extra heating zones. It is usually caused by a loose wiring connection or an internal electronic failure within the expansion module itself, meaning the boiler can no longer send or receive instructions from those parts of your system.
DIY fix possible
Locate the power switch (fused spur) for the boiler.Turn the power off, wait for 30 seconds, and turn it back on to see if the connection resets.Check if any external solar controllers or expansion boxes have lost power or been unplugged.
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