Common problems guide

The most common Grant Vortex 15-20 problems

The faults most likely to send a Grant Vortex 15-20 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.
10 documented codes
6 most common
1 DIY-safe checks
5 engineer needed

The 6 most common faults

01
Burner lock-out High DIY-safe

Your boiler has detected a temporary issue with the burner and has safely shut itself down to prevent any damage.

What to try first

Check your oil tank to ensure you have enough fuel and that the supply valve is openWait 60 seconds for the internal control unit to resetGently press the illuminated red reset button located on the burner once

Est. cost
£120-250
Parts
Photocell, Ignition electrodes, Oil nozzle
Full guide for Burner lock-out
Parts most often replaced

on the Grant Vortex 15-20

PhotocellIgnition electrodesOil nozzleControl box

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Grant 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 10-code list for the Grant Vortex 15-20

Related guides

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