JJ-64 High
Your boiler is not receiving enough electrical power from your home's mains supply to operate safely.
Technical description: Supply voltage is below low limit
Typical repair cost: £90-250 (including labour)
DIY fix possible
Check if there is a power cut or brownout in your local areaEnsure your fuse box / consumer unit has not trippedTurn the boiler off at the fused spur switch, wait 30 seconds, and turn it back on to reset the electronics
Protect yourself from future repair bills
A boiler cover plan would cover faults like JJ-64 — no call-out fees, no surprises.
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Parts commonly replaced
- Printed Circuit Board (PCB)
- External Voltage Regulator
- Electrical Wiring
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