Potterton Puma 100e Fault codes & diagnostics

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

Combi Natural Gas 29.3 kW 1997-2005 Discontinued
GC Number 47-590-13

Replaced by: Potterton Puma 80/100 (next gen) / Potterton Promax range

Download the Potterton Puma 100e manualThe official installation and service manual (PDF), the document these fault codes were read from. 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 Puma 100e faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 5 documented codes

Tap any card for details

Lockout

Your boiler has stopped working because it couldn't successfully light the flame after three attempts, often caused by a temporary interruption in the gas supply or air in the lines.

High DIY-safe £100-250

What to check first

  1. Check that your gas supply is turned on at the meter and that other gas appliances are working
  2. Locate the reset button or turn the control knob to the reset position to clear the error
  3. Wait for the boiler to cycle through its ignition process automatically

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
Full explanation for Lockout
Lockout LED

Your boiler has shut itself down as a safety precaution because it has detected an internal fault or an interrupted gas supply.

High DIY-safe £100-350

What to check first

  1. Locate the reset button on the front control panel.
  2. Press and hold the reset button for several seconds.
  3. Check that your gas meter has credit and the isolation valve is open.

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Printed Circuit Board (PCB)
  • Overheat Thermostat
Full explanation for Lockout LED
Lockout light

Your boiler has stopped working because it cannot light its burner or has detected an internal safety problem and shut itself down to prevent damage or risks.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)
  • Overheat thermostat
Full explanation for Lockout light
Low System Pressure light

Your boiler has lost the water pressure it needs to circulate heat, so it has safely shut itself down until the system is topped back up.

High DIY-safe £80-150

What to check first

  1. Locate the filling loop (a silver flexi-hose) beneath the boiler.
  2. Open the valves on the filling loop to allow water into the system until the pressure gauge reads between 1 and 1.5 bar.
  3. Close the valves tightly and turn the boiler off and on again to reset.

Parts commonly replaced

  • Filling Loop
  • Pressure Relief Valve
  • Pressure Gauge
  • Expansion Vessel
Full explanation for Low System Pressure light
Pilot being extinguished

Your boiler's small starter flame has gone out, which has caused the system to shut down for safety because it can no longer safely ignite the main burner.

High Engineer only £120-280

Parts commonly replaced

  • Thermocouple
  • Overheat Thermostat
  • Gas valve
Full explanation for Pilot being extinguished
Status & diagnostic codes

1 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

Mains light Status This light simply shows that your boiler is receiving electrical power and is switched on.