Halstead Dimplex System Fault codes & diagnostics

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

System Natural GasLPG 20-30 kW 2005-2010 Discontinued

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17 High
Just want the most common Halstead Dimplex System faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 17 documented codes

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(No display)

Your boiler has lost all power and the control panel is completely blank, meaning the system cannot start or provide any heating.

High DIY-safe £90-280

What to check first

  1. Check if the main boiler power switch or fused spur is turned on.
  2. Inspect your home's main consumer unit (fuse box) to see if a circuit breaker has tripped.
  3. Check the fuse in the boiler's external wall switch; it typically requires a 3-amp fuse.

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal Glass Fuse
  • Transformer
Full explanation for (No display)
12

Your boiler has stopped working because it cannot light the flame and is detecting a fault with one of its internal heat sensors.

High Engineer only £120-£220

Parts commonly replaced

  • CH Flow Thermistor
  • Ignition Lead
  • Electrode Spark Generator
Full explanation for 12
13

Your boiler has stopped working because it cannot detect a flame or a heat sensor in the exhaust pipe has failed.

High Engineer only £140-£260

Parts commonly replaced

  • Flue Thermistor
  • Ignition Electrode
  • Gas Valve
Full explanation for 13
16

Your boiler has stopped working because one of its internal temperature sensors has broken or is sending an incorrect reading, preventing the system from firing up.

High Engineer only £90-£160

Parts commonly replaced

  • CH Return Thermistor (NTC sensor)
  • Wiring harness connector
Full explanation for 16
20

Your boiler is failing to light the fuel needed to create heat, likely due to a problem with the internal gas control system.

High Engineer only £220-380

Parts commonly replaced

  • Gas Valve
  • Ignition Electrode
  • PCB (Control Board)
Full explanation for 20
24

Your boiler has identified a communication problem with the fan, which means it cannot safely start the burner to provide heat or hot water.

High Engineer only £220-450

Parts commonly replaced

  • Fan motor
  • PCB (Printed Circuit Board)
  • Wiring harness
Full explanation for 24
32

Your boiler has failed to light a flame because it isn't receiving the necessary electricity or gas supply to start up.

High DIY-safe £100-280

What to check first

  1. Check if other gas appliances, like your hob, are working to ensure gas is reaching the house.
  2. Check your fuse box or consumer unit to see if a circuit breaker has tripped.
  3. Press the reset button on the boiler control panel once to see if it clears the error.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)
Full explanation for 32
34

Your boiler's internal computer is having a communication error or failing to detect a flame, often caused by an incorrect configuration chip.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main PCB

Related codes

Full explanation for 34
35

Your boiler's internal computer brain cannot communicate with its plug-in configuration chip, meaning the system won't fire up for heating or hot water.

High Engineer only £150-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Printed Circuit Board (PCB)
Full explanation for 35
36

Your boiler is failing to light because it cannot communicate with its internal control chip, usually occurring after a major circuit board repair.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Printed Circuit Board (PCB)
Full explanation for 36
37

Your boiler's internal computer chips are not communicating correctly or are mismatched, preventing the system from firing up.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Printed Circuit Board (PCB)
Full explanation for 37
38

Your boiler's main control board is struggling to communicate with its identity chip, often occurring after a recent repair or part replacement.

High Engineer only £120-280

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 38
39

Your boiler has failed to recognise its internal configuration chip, often because a replacement circuit board was not set up correctly.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 39
41

Your boiler is struggling to circulate water properly or the pressure is too low, causing it to shut down shortly after lighting.

High DIY-safe £100-£280

What to check first

  1. Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.
  2. If the pressure is low, use the filling loop valves to top the system up with water.
  3. Ensure all radiator valves and boiler isolation valves are fully open.
  4. Restart the boiler once the correct pressure is reached.

Parts commonly replaced

  • Water Pressure Sensor
  • Circulation Pump
  • Flow/Return Thermistors

Related codes

Full explanation for 41
42

Your boiler has detected that there is not enough water pressure or flow to operate safely, causing it to shut down shortly after lighting.

High DIY-safe £60-250

What to check first

  1. Check the pressure gauge on the front of the boiler or under the casing.
  2. If the needle is below 1 bar, use the external filling loop valves to top the system up to 1.5 bar.
  3. Ensure all radiator valves and isolation valves under the boiler are fully open.
  4. Reset the boiler once the correct pressure is reached.

Parts commonly replaced

  • External filling loop
  • Circulating pump
  • Water pressure switch
  • Flow thermistor

Related codes

Full explanation for 42
50

Your boiler has failed to ignite and cannot detect its own control chip, meaning it has shut down for safety.

High Engineer only £120-280

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Printed Circuit Board (PCB)
  • Ignition Electrode
Full explanation for 50
No display

Your boiler has lost all power and the control panel is completely blank, meaning it cannot operate at all.

High DIY-safe £90-350

What to check first

  1. Check if your home's main electrical consumer unit (fuse box) has tripped.
  2. Ensure the boiler's isolation switch (usually a red-fused spur near the unit) is turned on.
  3. Check if the fuse inside the boiler's external plug or switch has blown and needs replacing.

Parts commonly replaced

  • External 3-amp fuse
  • Printed Circuit Board (PCB)
  • Display interface cable
Full explanation for No display