Baxi PLATINUM COMPACT 25 COMBI Fault codes & diagnostics

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

Combi Gas 2023-present
GC Number 47-077-71
Download the Baxi PLATINUM COMPACT 25 COMBI manualThe official installation and service manual (PDF), the document these fault codes were read from. PDF

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Severity at a glance

Each cell = one fault code. Hover to identify.
12 High 4 Medium 1 Low

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
47-077-71 PLATINUM COMPACT 25 COMBI 2023–present

Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.

All 17 documented codes

Tap any card for details

09

Your boiler has lost reliable communication with its internal electronic brain, causing it to lock out for safety.

High Engineer only £150-300

Parts commonly replaced

  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

15

Your boiler has lost proper communication between its internal electronic brain and its wiring connections.

High Engineer only £100-250

Parts commonly replaced

  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

20

Your boiler is displaying a flashing error code, which usually indicates a temporary internal glitch or safety lock out that needs to be reset.

Medium DIY-safe £90-200

What to check first

  1. Turn the boiler's main power switch off and on again after a few seconds.
  2. Locate the reset button on your Baxi boiler control panel and hold it for about 5 seconds.
  3. Check that your home has a stable power supply and the boiler is securely plugged in.

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Control Panel

Related codes

28

Your boiler has detected an ignition failure or flame detection problem and has safely locked itself out to prevent gas from building up.

High Engineer only £150-300

Parts commonly replaced

  • Ignition lead
  • Electrodes
  • Gas valve
  • Printed Circuit Board (PCB)

Related codes

40

Your boiler is displaying a general flashing error indicator, which means the system has detected a temporary operational fault and locked out for safety.

High Engineer only £90-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Temperature Sensor

Related codes

109

Your boiler has detected that the burner has successfully lit, but this informational status code may indicate a temporary cycle monitoring check or require professional attention if it persists and locks out the system.

Low Engineer only

Parts commonly replaced

  • Flame Sensor
  • Gas Valve
  • PCB

Related codes

110

Your boiler has stopped working because a safety sensor has detected that it is running too hot.

High Engineer only £150-300

Parts commonly replaced

  • NTC Thermistor
  • Heat Exchanger
  • Automatic Bypass Valve
  • Circulating Pump

Related codes

118

Your boiler has detected an issue with water pressure inside the system, causing it to flash an error and temporarily stop working.

High DIY-safe

What to check first

  1. Locate the filling loop underneath your boiler.
  2. Open the valves slowly to top up the system pressure until the gauge reads between 1 and 1.5 bar.
  3. Close the valves tightly and reset the boiler.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
  • Expansion vessel

Related codes

125

Your boiler manages to start up, but the flame keeps going out after about a minute, leaving you without reliable heating or hot water.

High Engineer only £150-300

Parts commonly replaced

  • Flame sensor
  • Gas valve
  • PCB
  • Air pressure switch or fan

Related codes

128

Your boiler is lighting up briefly, but the flame keeps going out after just a few seconds.

High Engineer only £150-300

Parts commonly replaced

  • Electrodes
  • Gas Valve
  • PCB

Related codes

130

Your boiler's flame is unexpectedly going out while it is trying to run, which will leave you without heating or hot water.

High Engineer only £150-300

Parts commonly replaced

  • Flame electrode
  • Gas valve
  • Condensate trap
  • PCB

Related codes

133

Your boiler is trying to light up but is failing to detect a flame after a few attempts, so it has safely shut itself down.

High Engineer only £150-350

Parts commonly replaced

  • Ignition lead
  • Electrodes
  • Gas valve
  • PCB

Related codes

134

Your boiler has detected an internal communication or flashing error and has stopped working for safety.

High Engineer only £150-300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

135

Your boiler has experienced a general internal electronic glitch or communication error that is causing the display to flash.

Medium DIY-safe £100-250

What to check first

  1. Turn off the boiler at the main power switch or wall isolator.
  2. Wait for approximately 60 seconds to allow the internal system to fully reset.
  3. Turn the power back on and check if the flashing error clears.

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness

Related codes

160

Your boiler's internal fan is continuing to run longer than expected, which usually points to a sensor or circuit board communication issue rather than an immediate safety hazard.

Medium Engineer only £150-300

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)

Related codes

321

Your boiler is displaying a general flashing error indicator, which usually means the system needs to be reset or has detected a temporary operational hiccup.

Medium DIY-safe £80-£150

What to check first

  1. Check the system pressure gauge to ensure it is between 1 and 1.5 bar.
  2. Locate the reset button or turn the mode dial to the reset position for a few seconds.
  3. Wait to see if the boiler fires up normally after the reset.

Parts commonly replaced

  • Printed Circuit Board
  • User Interface Panel

Related codes

384

Your boiler has temporarily stopped working because it has detected an internal communication or electrical connection problem.

High Engineer only £150-300

Parts commonly replaced

  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

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