Dimplex System 30 Fault codes & diagnostics

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

System Natural Gas 30 kW 2008 onwards Discontinued
GC Number 41-149-01
Download the Dimplex System 30 manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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Severity at a glance

Each cell = one fault code. Hover to identify.
22 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
41-149-01 System 30 2008–present
Just want the most common Dimplex System 30 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 22 documented codes

Tap any card for details

(No display)

Your boiler appears to have no power and is completely unresponsive, meaning it cannot provide heating or hot water.

High DIY-safe £90-280

What to check first

  1. Check if other appliances in the house are working to rule out a general power cut
  2. Check your home's main electrical consumer unit (fuse box) to see if a circuit has tripped
  3. Ensure the boiler's isolation switch (usually a fused spur near the boiler) is turned on
  4. Replace the fuse in the boiler's external fused spur switch with a 3-amp fuse

Parts commonly replaced

  • Internal PCB (Printed Circuit Board)
  • Glass fuse
  • Wiring harness

Related codes

Full explanation for (No display)
1

Your boiler has shut down because the water inside the unit has become too hot, likely due to a circulation problem or a blockage.

High DIY-safe £120-350

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the boiler pressure is between 1.0 and 1.5 bar
  3. Switch the boiler off and back on to attempt a reset once the system has cooled down

Parts commonly replaced

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

Related codes

Full explanation for 1
4

Your boiler is failing to light the gas, meaning it cannot create the heat needed for your heating or hot water.

High DIY-safe £120-350

What to check first

  1. Check that your gas emergency control valve is in the open position
  2. If you have a prepay meter, check that you have credit available
  3. Press the reset button to see if the system restarts normally

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Spark generator
  • Flame sensing probe

Related codes

Full explanation for 4
5

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

High DIY-safe £100-350

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, like a hob, are working correctly
  3. Press the reset button to see if the boiler restarts

Parts commonly replaced

  • Flame sensing electrode
  • Gas valve
  • Ignition lead

Related codes

Full explanation for 5
6

Your boiler has shut down because the internal water temperature has become too hot.

High DIY-safe £100-£350

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the boiler pressure is between 1 and 1.5 bar
  3. Press the reset button and wait for the boiler to restart

Parts commonly replaced

  • Circulating pump
  • NTC thermistor
  • Main heat exchanger

Related codes

Full explanation for 6
7

Your boiler has sensed that the exhaust gases are too hot and has shut down as a safety precaution to prevent heat damage.

High Engineer only £120-350

Parts commonly replaced

  • Flue thermistor
  • Main heat exchanger (cleaning or replacement)
  • Gas valve (calibration)

Related codes

Full explanation for 7
11

Your boiler thinks it sees a flame even though the gas should be turned off, which is a safety conflict that prevents it from starting.

High Engineer only £120-£350

Parts commonly replaced

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

Related codes

Full explanation for 11
12

Your boiler has stopped working because it cannot detect the correct temperature of the water leaving the unit, preventing it from firing up.

High Engineer only £120-£200

Parts commonly replaced

  • CH Flow Thermistor (NTC sensor)
  • Wiring Harness

Related codes

Full explanation for 12
13

Your boiler has failed to ignite a flame because it detected a problem with the sensor that monitors exhaust gases.

High Engineer only £120-220

Parts commonly replaced

  • Flue thermistor
  • Thermistors wiring loom
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 13
16

Your boiler has stopped heating because one of its internal temperature sensors is providing an incorrect reading or has failed completely.

High Engineer only £120-£190

Parts commonly replaced

  • CH Return thermistor (NTC sensor)
  • Wiring harness connector

Related codes

Full explanation for 16
Showing 11–20 of 22
20

Your boiler is failing to light a flame because the internal gas valve is not operating correctly, meaning your heating and hot water will not work.

High Engineer only £250-£450

Parts commonly replaced

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

Related codes

Full explanation for 20
24

Your boiler has detected a communication problem with its internal fan, causing the system to get stuck in a safety cycle and preventing the burner from lighting.

High Engineer only £180-320

Parts commonly replaced

  • Extraction Fan
  • Main PCB
  • Wiring Loom

Related codes

Full explanation for 24
32

Your boiler has failed to ignite, which is likely due to an electrical supply issue or a problem with the gas delivery.

High DIY-safe £100-350

What to check first

  1. Check that your gas meter has credit and the isolation valve is open
  2. Ensure other gas appliances in your home are working
  3. Try resetting the boiler using the control panel
  4. Check your home's fuse box/consumer unit to ensure the boiler circuit hasn't tripped

Parts commonly replaced

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

Related codes

Full explanation for 32
34

Your boiler has failed to light because its internal computer chip has an error and is not communicating correctly with the main control board.

High Engineer only £180-350

Parts commonly replaced

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

Related codes

Full explanation for 34
35

Your boiler has lost its connection with its internal control chip or cannot detect a flame, causing the system to shut down for safety.

High Engineer only £120-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main Control Board (PCB)
  • Flame Sensing Electrode

Related codes

Full explanation for 35
36

Your boiler has failed to ignite because of a communication fault within its internal control chip.

High Engineer only £140-£260

Parts commonly replaced

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

Related codes

Full explanation for 36
37

Your boiler's internal computer chips are not communicating correctly or don't match, preventing the appliance from firing up.

High Engineer only £180-350

Parts commonly replaced

  • BCC (Boiler Chip Card)
  • PCB (Main Control Board)

Related codes

Full explanation for 37
38

Your boiler's internal computer chip is not communicating correctly with the main control board, preventing the burner from lighting.

High Engineer only £120-350

Parts commonly replaced

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

Related codes

Full explanation for 38
39

Your boiler's main control chip is either missing, faulty, or has failed to communicate with the system, meaning the boiler cannot ignite for safety reasons.

High Engineer only £120-280

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 and 1.5 bar.
  2. If the pressure is low, use the external filling loop to top it up to the correct level.
  3. Ensure all radiator valves and isolation valves under the boiler are fully open.

Parts commonly replaced

  • Circulation pump
  • Flow/Return thermistors
  • Pressure sensor

Related codes

Full explanation for 41
Showing 21–22 of 22
42

Your boiler has detected that there is not enough water flowing through the system or the pressure is too low to work safely.

High DIY-safe £100-£250

What to check first

  1. Check the pressure gauge on the front of the boiler; it should ideally be between 1 and 1.5 bar.
  2. If the pressure is low, use the filling loop valves to top up the system until the needle reaches the 1.5 bar mark.
  3. Ensure all radiator valves are open and not stuck shut.
  4. Press the reset button to see if the boiler restarts.

Parts commonly replaced

  • Circulation pump
  • Water pressure switch
  • Expansion vessel

Related codes

Full explanation for 42
50

Your boiler has lost communication with its internal control chip or has failed to light the burner, meaning your heating and hot water will not work.

High Engineer only £150-£350

Parts commonly replaced

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

Related codes

Full explanation for 50