High
FAIL POINT K on Worcester Bosch 24/28CDi II RSF

Your boiler has encountered a general electrical failure, likely caused by moisture or damage to the internal brain of the unit.

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

Other faults not covered by above - Light indication during fault not covered by above details. Control board is likely to be wet or damaged or malfunctioning.

From this model's manual
Verified against the Worcester Bosch 24 28cdi Ii Rsf installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler's internal computer experiences a critical communication failure or hardware malfunction. The most common reason is moisture ingress from a small leak or heavy condensation getting onto the electrical circuits, though the components can also simply fail over time due to heat stress.

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.

Find a Gas Safe engineer
Search the official register →

Avoid the next call-out bill

A cover plan would handle faults like FAIL POINT K: no call-out fees, no surprise bills.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related guides you might find useful