E30 High
Your boiler has sensed that the water is not moving through the system fast enough, causing it to heat up too quickly and shut down for safety.
Technical description: Difference between flow and return temperatures too high – check circulation.
Typical repair cost: £100-350 (including labour)
DIY fix possible
Check that your radiator valves are open, particularly any with thermostatic heads.Ensure the boiler pressure gauge is between 1 and 1.5 bar, topping up if necessary.Listen for air in the system and bleed your radiators to remove any trapped pockets.
Protect yourself from future repair bills
A boiler cover plan would cover faults like E30 — no call-out fees, no surprises.
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Parts commonly replaced
- Central heating pump
- Flow/Return thermistors
- Main heat exchanger (flushing)
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