Potterton Housewarmer Fault codes & diagnostics

3 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

RegularSystem Natural Gas 8.8 kW 1994-2003 Discontinued
GC Numbers 44-590-1844-590-19
Download the Potterton Housewarmer manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Just want the most common Potterton Housewarmer faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 3 documented codes

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Lockout (Red LED)

Your boiler has stopped trying to light itself because the small starter flame failed to ignite within the safety time limit.

High DIY-safe £80-160

What to check first

  1. Locate the reset button or turn the control knob to the 'Reset' position.
  2. Hold for 5 seconds and release.
  3. If the fault persists after three attempts, contact a Gas Safe engineer to clear air from the gas line.

Parts commonly replaced

  • Ignition Electrode
  • Thermocouple
  • Gas Valve
Full explanation for Lockout (Red LED)
Overheat (Red LED)

Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage.

High Engineer only £120-250

Parts commonly replaced

  • Overheat thermostat
  • Pump
  • PCB
Full explanation for Overheat (Red LED)
Red LED (Overheat)

Your boiler has switched itself off because it has gotten too hot, likely due to a circulation problem or a temporary blockage.

High DIY-safe £100-250

What to check first

  1. Ensure all radiator valves are fully open and there is no air in the system.
  2. Allow the boiler to cool down completely for at least 20 minutes.
  3. Locate the manual reset button (usually behind the front flap or underneath) and press it firmly to clear the red light.

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • Thermistor
Full explanation for Red LED (Overheat)