28 High
Your boiler has detected that there is not enough water pressure or flow to operate safely, which is preventing your heating and hot water from working.
Technical description: Failed low water – pressure switch or pump, possible issue with pump, incorrect system pressure or the low water switch pressure needs replacing
Typical repair cost: £120-280 (including labour)
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.If the pressure is too low, use the external filling loop to top up the system with water.Ensure all radiator valves are open and bleed any air from the radiators.Turn the boiler off and back on again to reset the fault.
Protect yourself from future repair bills
A boiler cover plan would cover faults like 28 — no call-out fees, no surprises.
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Parts commonly replaced
- Low water pressure switch
- Circulation pump
- Expansion vessel
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