Baxi Profile Prima Fault codes & diagnostics

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

Regular Natural Gas 15-29 kW 1997-2005 Discontinued

Replaced by: Potterton Promax

No manual available yet We don't hold the official service manual for this model yet. We're sourcing it — check back soon.

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
6 High 1 Medium 3 Low
Just want the most common Baxi Profile Prima faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 10 documented codes

Tap any card for details

1 red flash

Your boiler has detected that it is getting too hot or the water isn't moving through the system correctly, causing it to shut down for safety.

High DIY-safe £90-180

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the system pressure is at the correct level (usually 1.0 to 1.5 bar)
  3. Check for any visible leaks around the boiler and pipework

Parts commonly replaced

  • Temperature sensor (NTC thermistor)
  • Circulation pump
  • Overheat thermostat

Related codes

Full explanation for 1 red flash
2 red flashes

Your boiler has become too hot and has automatically shut down for safety purposes.

High DIY-safe £100-250

What to check first

  1. Ensure all radiator valves are fully open and there are no obstructions to water flow.
  2. Wait for the boiler to cool down completely.
  3. Locate the manual reset button (usually tucked under the bottom of the boiler) and press it firmly to restart the unit.

Parts commonly replaced

  • Circulation pump
  • Overheat thermostat
  • Pressure relief valve
Full explanation for 2 red flashes
3 green flashes

Your boiler has momentarily lost its flame and is trying to restart itself, which often indicates a minor interruption in the gas supply or a slightly dirty component.

Medium DIY-safe £80-160

What to check first

  1. Monitor the boiler for several minutes to see if the flame stabilizes on its own
  2. Check that other gas appliances in the home are working correctly to rule out a supply issue
  3. Perform a manual reset of the boiler if the fault does not clear automatically
  4. Contact a Gas Safe engineer if the fault progresses to 3 red flashes

Parts commonly replaced

  • Flame sense electrode
  • Gas valve
  • Flame rectification lead

Related codes

Full explanation for 3 green flashes
3 red flashes

Your boiler has tried to light itself several times but cannot establish a flame, meaning your heating and hot water will not work.

High DIY-safe £100-280

What to check first

  1. Check if other gas appliances, like a hob, are working to ensure gas is reaching the property
  2. Check that your gas meter has credit if you use a pre-payment meter
  3. Switch the boiler off and on again at the fused spur switch to attempt a reset

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 3 red flashes
4 green flashes

Your boiler has temporarily lost communication between its internal electronic parts but should automatically try to restart itself shortly.

Low DIY-safe £180-350

What to check first

  1. Wait for the boiler to automatically reset itself
  2. Turn the main power switch to the boiler off and back on again
  3. Ensure any external room thermostats or timers are set correctly

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 4 green flashes
4 red flashes

Your boiler's internal safety system has detected that the fan responsible for clearing exhaust gases is not working correctly, preventing the boiler from starting.

High Engineer only £180-£350

Parts commonly replaced

  • Fan Assembly
  • Air Pressure Switch
  • PCB

Related codes

Full explanation for 4 red flashes
5 green flashes

Your boiler has experienced a brief communication glitch with its internal computer brain, which it should fix by itself automatically.

Low DIY-safe £0-280

What to check first

  1. Wait up to 10 minutes for the boiler to automatically reset itself
  2. Turn the boiler off at the main electrical switch and back on again after 30 seconds
  3. If the fault persists or recurs frequently, contact a Gas Safe engineer to check the electrical connections

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Loom

Related codes

Full explanation for 5 green flashes
5 red flashes

Your boiler's computer has lost its settings or is failing to communicate with its memory chip, causing the system to stop working.

High Engineer only £200-£450

Parts commonly replaced

  • Parameter Storage Unit (PSU)
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 5 red flashes
6 green flashes

Your boiler has encountered a minor temporary glitch and is currently attempting to restart itself automatically.

Low DIY-safe £0-120

What to check first

  1. Wait up to 15 minutes for the boiler to complete its self-reset process
  2. Check that your external controls or thermostat are calling for heat
  3. If the flashing continues, turn the power to the boiler off and back on again at the fused spur switch

Parts commonly replaced

  • None (Software reset)
  • Printed Circuit Board (PCB) if fault persists
Full explanation for 6 green flashes
6 red flashes

Your boiler has detected a general internal fault that is preventing it from firing up safely, often caused by a component failing to communicate properly.

High Engineer only £120-280

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Internal Fuse
  • Gas Valve

Related codes

Full explanation for 6 red flashes
Status & diagnostic codes

1 operating states & engineer diagnostics

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

1 green flash Status Your boiler has reached its set temperature and is temporarily turning off because your home is warm enough.