Common problems guide

The most common Malvern 20/26 problems

The faults most likely to send a Malvern 20/26 into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.
5 documented codes
5 most common
0 DIY-safe checks
5 engineer needed

The 5 most common faults

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Malvern shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
See the full 5-code list for the Malvern 20/26

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →