D.70 Low
Your boiler is currently stuck in a diagnostic test mode that overrides its normal settings, which usually happens during a service or repair.
Technical description: Set diverter valve position
Typical repair cost: £0-90 (including labour)
DIY fix possible
Locate the display panel on the front of the boilerPress the 'Reset' button (marked with a flame or cross symbol) for one secondWait for the boiler to restart and check if the 'D.70' code has disappeared
Protect yourself from future repair bills
A boiler cover plan would cover faults like D.70 — no call-out fees, no surprises.
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Parts commonly replaced
- None (Software reset)
- PCB (only if code persists after reset)
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