Common problems guide

The most common Grant Vortex Eco External Floor Standing problems

The faults most likely to send a Grant Vortex Eco External Floor Standing 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.
18 documented codes
6 most common
2 DIY-safe checks
4 engineer needed

The 6 most common faults

01
Lock-out (light on) High DIY-safe

Your boiler has stopped itself from running as a safety precaution because the fuel failed to ignite properly.

What to try first

Check your external oil tank has enough fuel and the isolation valve is fully openLocate the red reset button on the burner casing or control boxPress and hold the reset button for 3 seconds then release to attempt a restart

Est. cost
£120-250
Parts
Photocell, Ignition electrodes, Oil pump
Full guide for Lock-out (light on)
02
LOW PRESSURE indicator lit High DIY-safe

Your boiler has stopped working because the amount of water in your heating system is too low to run safely.

What to try first

Locate the external filling loop, which is a flexible silver hose connecting your cold water mains to your heating pipes.Open the valves at both ends of the filling loop slowly to let water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves tightly to prevent over-pressurizing the system.

Est. cost
£0-£100
Parts
Pressure Relief Valve, Pressure Gauge, Filling Loop
Full guide for LOW PRESSURE indicator lit
03
BURNER indicator flashing High Engineer

Your boiler's main control computer is experiencing an error, which has caused it to stop the burner from operating to prevent further issues.

Est. cost
£250-450
Parts
Control PCB, Wiring harness
Full guide for BURNER indicator flashing
04
DHW PUMP (FLASHING) High Engineer

Your boiler is struggling to detect the temperature of your hot water supply, which means it will likely stop heating your water until a faulty sensor or internal control board is replaced.

Est. cost
£150-300
Parts
Store thermistor, Printed Circuit Board (PCB)
Full guide for DHW PUMP (FLASHING)
05
BURNER (FLASHING) High Engineer

Your boiler's electronic brain is unable to communicate correctly, which has caused it to lock out to prevent unsafe operation.

Est. cost
£250-450
Parts
Control PCB, Wiring loom
Full guide for BURNER (FLASHING)
06
CH PUMP indicator Fast flash High Engineer

Your boiler's temperature sensor is failing to communicate properly, which is preventing it from heating your water correctly.

Est. cost
£120-200
Parts
CH Flow Thermistor, Wiring harness
Full guide for CH PUMP indicator Fast flash
Parts most often replaced

on the Grant Vortex Eco External Floor Standing

PhotocellIgnition electrodesOil pumpControl boxPressure Relief ValvePressure Gauge

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 18-code list for the Grant Vortex Eco External Floor Standing

Related guides

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