Potterton Osprey CF 125 Fault codes & diagnostics

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

Regular Natural Gas 36.6 kW 1994-2005 Discontinued
GC Numbers 41-589-3341-589-4441-589-4541-589-6241-590-78
Download the Potterton Osprey CF 125 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 Osprey CF 125 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 3 documented codes

Tap any card for details

Boiler Safety Overheat neon

Your boiler has switched itself off because it has become too hot to operate safely.

High DIY-safe £100-280

What to check first

  1. Turn the boiler off and allow it to cool down for at least 30 minutes.
  2. Ensure all radiator valves are open and there is no air trapped in the system.
  3. Unscrew the small black cap on the front control panel and press the reset button firmly.

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • System Thermistor
Full explanation for Boiler Safety Overheat neon
Flame Failure neon

Your boiler has lost its flame while it was supposed to be running, causing the system to shut down for safety.

High DIY-safe £120-350

What to check first

  1. Check if other gas appliances, like a hob, are working to ensure gas is reaching the property
  2. Check if your gas meter has credit (if applicable)
  3. Press the reset button once to see if the boiler restarts

Parts commonly replaced

  • Flame sensing electrode
  • Gas valve
  • Ignition lead
  • PCB
Full explanation for Flame Failure neon
Overheat condition

Your boiler has become too hot and has automatically turned its pilot light off as a safety measure to prevent damage.

High Engineer only £120-250

Parts commonly replaced

  • Overheat thermostat
  • Pump
  • Diverter valve
  • PCB
Full explanation for Overheat condition
Status & diagnostic codes

6 operating states & engineer diagnostics

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

125 Status Your boiler has detected a lack of water flow or a circulation issue, meaning it has shut down to prevent internal damage. 150 Status Your boiler is failing to light because it has detected an issue with the air supply or exhaust ventilation system. 180 Status Your boiler has detected an issue with its internal communication or electronic control system and has shut down to prevent damage. 220 Status Your boiler has detected an issue with the air supply or exhaust fumes, meaning it has safely shut down to prevent the risk of harmful gases building up in your home. Burner On Neon Status Your boiler is operating normally and is currently heating your home or water. Power On Neon Status This light simply shows that your boiler is receiving electrical power and is switched on.