High
b18 on Ideal Imax W

Your boiler is temporarily pausing because it is struggling to move water through the system, often due to a blocked filter or a trapped air pocket.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Blocking code (appears alternating with 9)

From this model's manual
Verified against the Ideal/Ideal Imax W installation & service manual, page 50.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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All 42 fault codes on the Imax W

Seeing a different code? Every code this model can display, in one place.

36b 19b 24b 25b 26b 30b 33b 38b 61b 65E 00E 02E 03E 04E 05E 06E 07E 08E 11E 12E 13E 14E 15E 16E 17E 19E 25E 28E 29E 30E 31E 32E 33E 37E 38E 44E 60E 61E 65E18E36

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