BoilerFaultCodes 8.iii Medium
Your boiler's water circulation system has become clogged with internal sludge or debris, making the pump struggle and create a grinding or rattling noise.
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.
Technical description: Pump noisy - Debris in pump
Typical repair cost £150-300 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 8.iii — no call-out fees, no surprises.
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