Dimplex Combi 38 Fault codes & diagnostics

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

Combi Natural Gas 38 kW 2008 onwards Discontinued
GC Number 47-149-01
Download the Dimplex Combi 38 manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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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.
23 High
Versions & GC numbers

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
47-149-01 Combi 38 2008–present
Just want the most common Dimplex Combi 38 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 23 documented codes

Tap any card for details

(No display)

Your boiler has no power and the screen is blank, meaning it cannot operate at all to provide heating or hot water.

High DIY-safe £80-250

What to check first

  1. Check if the boiler's power switch is turned on
  2. Check your home's main fuse box (RCD) to see if a circuit has tripped
  3. Check the fuse in the boiler's fused spur switch (the wall switch near the boiler)

Parts commonly replaced

  • Internal Glass Fuse
  • Printed Circuit Board (PCB)
  • Transformer

Related codes

Full explanation for (No display)
1

Your boiler has shut down because it has reached a dangerously high temperature to prevent damage to the internal components.

High Engineer only £120-£350

Parts commonly replaced

  • Circulation pump
  • Overheat thermostat
  • Diverter valve
  • Heat exchanger

Related codes

Full explanation for 1
4

Your boiler is trying to start up but cannot light the gas flame needed to provide heat and hot water.

High DIY-safe £120-350

What to check first

  1. Check if other gas appliances, like a cooker, are working to ensure gas is reaching the property
  2. Verify that your gas cupboard valves are open or that you have credit on your meter
  3. Press the Reset button on the boiler control panel once to see if the system restarts

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Flame Sensing Probe

Related codes

Full explanation for 4
5

Your boiler has started to heat up but the flame has unexpectedly gone out, causing the system to shut down for safety.

High DIY-safe £120-350

What to check first

  1. Check that your gas emergency control valve is open and you have credit on your gas meter
  2. Check if other gas appliances in your home, such as a hob, are working correctly
  3. Reset the boiler by following the instructions in your user manual

Parts commonly replaced

  • Flame sensing electrode
  • Gas valve
  • Ignition lead

Related codes

Full explanation for 5
6

Your boiler has shut down to protect itself because the water inside has become far too hot.

High Engineer only £120-350

Parts commonly replaced

  • Circulation pump
  • Overheat thermostat
  • Heat exchanger
  • Thermistor

Related codes

Full explanation for 6
7

Your boiler has shut down because the exhaust fumes have reached an unsafe temperature, triggered to prevent damage to the internal components.

High Engineer only £150-350

Parts commonly replaced

  • Secondary heat exchanger
  • Main heat exchanger (descale/flush)
  • Flue NTC sensor

Related codes

Full explanation for 7
11

Your boiler thinks it sees a flame even though it hasn't turned the gas on yet, which is a safety conflict that stops it from starting.

High Engineer only £120-300

Parts commonly replaced

  • Flame sense electrode
  • Gas valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 11
12

Your boiler has stopped providing heating and hot water because a internal heat sensor has failed, preventing the system from starting up.

High Engineer only £120-190

Parts commonly replaced

  • Central Heating (CH) Flow NTC Thermistor
  • Wiring harness

Related codes

Full explanation for 12
13

Your boiler has shut down because a temperature sensor in the exhaust pipe has detected a fault or the system is unable to safely verify that a flame has been established.

High Engineer only £120-220

Parts commonly replaced

  • Flue Thermistor (NTC)
  • Ignition Electrode
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 13
16

Your boiler has stopped working because a sensor that monitors the temperature of the water returning from your radiators has developed a fault.

High Engineer only £90-160

Parts commonly replaced

  • CH Return NTC Thermistor
  • Connecting wiring harness

Related codes

Full explanation for 16
Showing 11–20 of 23
20

Your boiler is failing to light because gas isn't reaching the burner properly, meaning you will have no heating or hot water.

High Engineer only £180-£350

Parts commonly replaced

  • Gas Valve
  • Ignition Lead
  • Main PCB

Related codes

Full explanation for 20
24

Your boiler has identified a communication problem with the internal fan, causing the system to shut down for safety while the fan runs continuously.

High Engineer only £180-£350

Parts commonly replaced

  • Fan assembly
  • Fan wiring harness
  • Main circuit board (PCB)

Related codes

Full explanation for 24
32

Your boiler has stopped working because it cannot detect a flame or has lost its electrical connection, meaning you currently have no heating or hot water.

High DIY-safe £120-350

What to check first

  1. Check if other gas appliances, like a hob, are working to ensure gas supply is active
  2. Ensure the boiler is plugged in and the fused spur switch is turned on
  3. Check your consumer unit/fuse box for any tripped switches
  4. Press the Reset button on the boiler control panel

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 32
34

Your boiler's main control board has encountered a memory error or is using the wrong configuration chip, preventing the unit from lighting a flame.

High Engineer only £180-350

Parts commonly replaced

  • Main PCB
  • Boiler Chip Card (BCC)

Related codes

Full explanation for 34
35

Your boiler has a communication issue with its electronic brain, usually meaning a specific security chip is missing or faulty.

High Engineer only £150-320

Parts commonly replaced

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

Related codes

Full explanation for 35
36

Your boiler has stopped working because its internal computer chip is faulty or communication with the control board has failed.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main PCB

Related codes

Full explanation for 36
37

Your boiler's computer control chip is missing or not communicating correctly with the main circuit board, preventing the system from firing up.

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 main control board has been replaced or reset but doesn't recognize the specific identity chip required to operate your model.

High Engineer only £100-250

Parts commonly replaced

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

Related codes

Full explanation for 38
39

Your boiler's main control board is having trouble communicating with its identity chip, often occurring after recent repair work.

High Engineer only £120-350

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 it to shut down shortly after it lights.

High DIY-safe £80-250

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 to top it up.
  3. Ensure all radiator valves and external isolation valves are fully open.

Parts commonly replaced

  • Circulation pump
  • Flow temperature sensor
  • Return temperature sensor

Related codes

Full explanation for 41
Showing 21–23 of 23
42

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

High DIY-safe £80-250

What to check first

  1. Check the pressure gauge on the front of the boiler; it should ideally be between 1.0 and 1.5 bar.
  2. If the pressure is below 1.0, use the external filling loop to top up the system with water until the gauge reaches 1.2 bar.
  3. Ensure all radiator valves are open and that the pump is not making loud grinding noises.
  4. Reset the boiler to clear the fault code once the pressure is restored.

Parts commonly replaced

  • Filling loop
  • Circulating pump
  • Water pressure switch
  • External expansion vessel

Related codes

Full explanation for 42
50

Your boiler has failed to recognize its internal software chip or has failed to ignite, causing the system to shut down for safety.

High Engineer only £120-350

Parts commonly replaced

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

Related codes

Full explanation for 50
No light display when tap on

Your boiler is not detecting when you turn on the hot tap, so it isn't firing up to heat the water.

High Engineer only £120-£200

Parts commonly replaced

  • DHW Flow Switch
  • Hot Water Thermistor (NTC Sensor)

Related codes

Full explanation for No light display when tap on