Halstead Dimplex Combi Fault codes & diagnostics

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

Combi Natural Gas 24-28 kW 2000-2003 Discontinued

Replaced by: Halstead Eden VB

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
17 High
Just want the most common Halstead Dimplex Combi faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 17 documented codes

Tap any card for details

(No display)

Your boiler has no power and the screen is completely blank, meaning it cannot provide any heating or hot water until electrical flow is restored.

High DIY-safe £100-£350

What to check first

  1. Check if other appliances or lights in your home are working to rule out a general power cut.
  2. Inspect your home's main consumer unit (fuse box) to see if a circuit breaker has tripped.
  3. Check the fused spur switch located next to your boiler; ensure it is turned on and try replacing the 3-amp fuse inside.

Parts commonly replaced

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

Your boiler has stopped working because a sensor that monitors water temperature has failed, preventing the system from firing up.

High Engineer only £90-160

Parts commonly replaced

  • Central Heating Flow Thermistor (NTC sensor)
  • Wiring harness
Full explanation for 12
13

Your boiler has stopped working because its internal safety sensors can no longer monitor the temperature of the exhaust gases.

High Engineer only £120-£200

Parts commonly replaced

  • Flue Thermistor (NTC sensor)
  • Wiring Harness
Full explanation for 13
16

Your boiler has stopped working because a temperature sensor on the pipework is broken or sends an incorrect signal, preventing the burner from lighting.

High Engineer only £90-160

Parts commonly replaced

  • CH Return Thermistor (NTC Sensor)
  • Wiring harness / Connector
Full explanation for 16
20

Your boiler is not lighting because it is unable to draw the gas it needs to create a flame.

High Engineer only £220-£380

Parts commonly replaced

  • Gas Valve
  • Ignition Lead
  • Printed Circuit Board (PCB)
Full explanation for 20
24

Your boiler has stopped working because the internal computer cannot communicate with the fan that clears exhaust gases.

High Engineer only £180-350

Parts commonly replaced

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

Your boiler has failed to ignite because the internal control board is not receiving or sending the electricity required to create a flame.

High Engineer only £180-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Gas Valve
  • Wiring Loom
Full explanation for 32
34

Your boiler's computer control board has encountered a software data error or is mismatched with the boiler, causing it to stop providing heating and hot water.

High Engineer only £250-£450

Parts commonly replaced

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

Related codes

Full explanation for 34
35

Your boiler's electronic control board is unable to recognize a small coding chip that tells it how to operate correctly.

High Engineer only £180-350

Parts commonly replaced

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

Related codes

Full explanation for 35
36

Your boiler's electronic command chip is failing to communicate with the main control board, preventing the system from firing up safely.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main PCB

Related codes

Full explanation for 36
37

Your boiler's main control board has lost connection with its configuration chip or the chip is incorrect, meaning the system cannot safely confirm if the burner is lit.

High Engineer only £180-350

Parts commonly replaced

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

Related codes

Full explanation for 37
38

Your boiler's electronic control board has a communication error with its security chip or is failing to recognize the ignition signal.

High Engineer only £180-£350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main Control PCB
Full explanation for 38
39

Your boiler's main control board has lost connection with its security chip or has been configured incorrectly following a repair.

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, causing the flame to cut out shortly after it starts to prevent overheating.

High DIY-safe £80-220

What to check first

  1. Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.
  2. If the pressure is too 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.

Parts commonly replaced

  • Circulation pump
  • Flow/Return thermistors
  • Pressure sensor

Related codes

Full explanation for 41
42

Your boiler has detected that there is not enough water flowing through the system or there is a lack of pressure to operate safely.

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 too low, use the filling loop valves under the boiler to top it up.
  3. Check that all radiator valves and boiler isolation valves are fully open.
  4. Ensure all radiators have been bled to remove trapped air.

Parts commonly replaced

  • Circulating pump
  • Water pressure switch
  • Flow thermistor (NTC sensor)

Related codes

Full explanation for 42
50

Your boiler's internal computer chip has lost communication or failed to recognise the burner, causing the system to shut down for safety.

High Engineer only £120-280

Parts commonly replaced

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

Your boiler is not reacting when you turn on the hot tap, leaving you with cold water and a blank display because it cannot sense that water is flowing.

High Engineer only £120-£240

Parts commonly replaced

  • DHW Flow Switch
  • DHW Thermistor (NTC Sensor)
  • Diverter Valve Actuator
Full explanation for No display