BoilerFaultCodesTechnical description
Maximum load test program error
What causes this fault?
This fault occurs when the boiler's internal diagnostic program fails to complete its high-performance test correctly. It is usually triggered manually by an engineer during a service or installation, and the error suggests that the system couldn't maintain the required heat output to finish the check. The most common reason is a sensor reading an unexpected temperature or the test being interrupted before the sequence was finished.
DIY fix possible
Turn the boiler power off at the wall or fused spurWait 60 secondsTurn the power back on and press the 'Reset' button (indicated by a flame with a line through it)
Find a Gas Safe engineer
Search the official register →