Common problems guide

The most common Potterton Suprima HE problems

The faults most likely to send a Potterton Suprima HE 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.
23 documented codes
6 most common
2 DIY-safe checks
4 engineer needed

The 6 most common faults

01
Overheat condition High DIY-safe

Your boiler has switched itself off because it has become too hot and needs a manual reset to restart.

What to try first

Locate the reset button on the control panel at the bottom of the boiler.Press and hold the reset button for at least 2 seconds.Wait for the flashing red light to turn green or stop flashing.Ensure your radiator valves are open and the system is pressurized.

Est. cost
£100-£250
Parts
Circulation pump, Overheat thermostat, Thermistor
Full guide for Overheat condition
02
27 High DIY-safe

Your boiler is struggling to circulate water, most likely because the pressure inside your system has dropped too low to operate safely.

What to try first

Locate the external filling loop, usually two valves with a flexible silver hose between them near the boiler or pipes.Open the valves slowly to allow water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves firmly and check the boiler display to see if the fault clears.

Est. cost
£90-250
Parts
Central heating pump, Pressure relief valve, Expansion vessel
Full guide for 27
03
Ignition LOCKOUT High Engineer

Your boiler has stopped working because it failed to light the flame after several attempts, so it has shut itself down for safety.

Est. cost
£150-350
Parts
Ignition electrode, Gas valve, PCB (Printed Circuit Board)
Full guide for Ignition LOCKOUT
04
Overheat LOCKOUT High Engineer

Your boiler has detected that it has become too hot and has automatically shut itself down to prevent internal damage.

Est. cost
£120-250
Parts
Overheat thermostat, Central heating pump, PCB
Full guide for Overheat LOCKOUT
05
PCB Fault High Engineer

Your boiler's internal computer has stopped working correctly and is no longer able to safely manage the heating system.

Est. cost
£250-400
Parts
Printed Circuit Board (PCB)
Full guide for PCB Fault
06
APS Stuck Fault High Engineer

Your boiler has detected that a safety sensor is stuck in the 'on' position before the fan has even started, so it has stopped working as a precaution.

Est. cost
£150-250
Parts
Air Pressure Switch, Venturi, Fan Assembly
Full guide for APS Stuck Fault
Parts most often replaced

on the Potterton Suprima HE

Circulation pumpOverheat thermostatThermistorCentral heating pumpPressure relief valveExpansion vessel

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 Potterton 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 23-code list for the Potterton Suprima HE

Related guides

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