Saunier Duval Themaclassic Plus F30E Fault codes & diagnostics

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

CombiSystem Natural Gas 30 kW 1999-2003 Discontinued
GC Numbers 47-920-3641-920-31

Replaced by: ThemaPlus F30 E

Download the Saunier Duval Themaclassic Plus F30E 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.
1 Emergency 21 High 2 Medium
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
41-920-31 Saunier Duval SB30e A 1999–2003
Just want the most common Saunier Duval Themaclassic Plus F30E faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 24 documented codes

Tap any card for details

0.5bar

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

High DIY-safe £80-120

What to check first

  1. Locate the filling loop, which is usually a metal braided hose underneath the boiler.
  2. Open the two valves on the filling loop to allow cold mains water into the system.
  3. Watch the pressure gauge on the front of the boiler until it reaches 1.5 bar, then firmly close both valves.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Expansion vessel
Full explanation for 0.5bar
01

Your boiler is failing to light because it cannot detect a flame or is not receiving a gas supply, causing it to shut down for safety.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)
Full explanation for 01
02

Your boiler has detected an issue with its internal ventilation system, meaning it has safely shut down because it cannot clear exhaust gases properly.

High Engineer only £150-300

Parts commonly replaced

  • Air pressure switch
  • Flue fan
  • Venturi tube

Related codes

Full explanation for 02
2.7bar

Your boiler's internal water pressure is currently too high, which can put unnecessary strain on the system's internal safety components.

High DIY-safe £80-120

What to check first

  1. Locate a radiator in your home that is easily accessible
  2. Use a radiator bleed key to gently open the bleed valve
  3. Release a small amount of water into a cloth or container until the pressure gauge on the boiler drops to between 1.0 and 1.5 bar

Parts commonly replaced

  • Pressure Relief Valve (PRV)
  • Expansion Vessel
Full explanation for 2.7bar
03

Your boiler is struggling to clear exhaust gases or draw in fresh air properly, so it has safely shut itself down to prevent unsafe operation.

High Engineer only £150-350

Parts commonly replaced

  • Air pressure switch
  • Flue fan assembly
  • Venturi
Full explanation for 03
05

Your boiler has detected that it has become too hot and has automatically shut down to prevent damage to its internal systems.

High Engineer only £120-250

Parts commonly replaced

  • NTC Sensor
  • Primary Heat Exchanger
  • Pump
  • Heating Circuit Filter

Related codes

Full explanation for 05
06

Your boiler's temperature sensor is failing to provide accurate readings, which has caused the system to stop heating your home as a safety precaution.

High Engineer only £120-220

Parts commonly replaced

  • NTC Flow Sensor
  • Wiring harness / Connection loom

Related codes

Full explanation for 06
07

Your boiler is struggling to detect the temperature of the water it is trying to heat for your taps and shower, so it has turned off that function to prevent any issues.

Medium Engineer only £120-200

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC Sensor
  • Wiring harness

Related codes

Full explanation for 07
09

Your boiler is struggling to accurately detect the water level inside the system, which is preventing it from safely starting up to provide heating or hot water.

High Engineer only £120-220

Parts commonly replaced

  • Water pressure sensor
  • Wiring harness

Related codes

Full explanation for 09
10

Your boiler is having trouble reading the temperature of the water returning from your radiators, which means it has stopped heating your home to prevent potential overheating.

High Engineer only £120-200

Parts commonly replaced

  • Return NTC thermistor sensor
  • Wiring harness

Related codes

Full explanation for 10
Showing 11–20 of 24
11

Your boiler's main control panel has lost communication with its internal computer, causing the system to stop working to prevent errors.

High Engineer only £150-300

Parts commonly replaced

  • Main printed circuit board (PCB)
  • Communication cable (MMI lead)

Related codes

Full explanation for 11
12

Your boiler is having a communication breakdown with its control panel, meaning it cannot receive your temperature or setting instructions.

Medium Engineer only £150-300

Parts commonly replaced

  • Control board (PCB)
  • Interface display module
  • Connecting wiring harness

Related codes

Full explanation for 12
13

Your boiler's electronic controller has encountered an internal error and has shut down for safety, meaning you currently have no heating or hot water.

High Engineer only £250-450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)

Related codes

Full explanation for 13
14

Your boiler has detected that the water inside the heating system has become too hot and has automatically shut down to prevent damage.

High Engineer only £120-250

Parts commonly replaced

  • NTC secondary sensor
  • Primary flow sensor
  • Heating pump

Related codes

Full explanation for 14
15

Your boiler is currently unable to control the flow of gas needed to ignite the flame, so it has safely shut down to prevent any issues.

High Engineer only £180-300

Parts commonly replaced

  • Stepper motor
  • Gas valve assembly
  • PCB

Related codes

Full explanation for 15
16

Your boiler has detected an issue with the valve that controls the supply of gas, meaning it has safely shut itself down to prevent any risk.

Emergency Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Printed circuit board (PCB)

Related codes

Full explanation for 16
17

Your boiler is struggling because the electricity supply it is receiving is too weak or unstable to run safely.

High Engineer only £120-250

Parts commonly replaced

  • Printed circuit board (PCB)
  • Electrical wiring harness

Related codes

Full explanation for 17
18

Your boiler's electronic control panel is experiencing a communication error, which means it cannot process your settings or send instructions to the heating system.

High Engineer only £150-300

Parts commonly replaced

  • Main PCB
  • User interface display module
  • Wiring harness

Related codes

Full explanation for 18
19

Your boiler has lost its connection to the heat sensor that measures the temperature of the water circulating to your radiators, so it has shut down to prevent overheating.

High Engineer only £120-220

Parts commonly replaced

  • NTC temperature sensor
  • Wiring harness
Full explanation for 19
20

Your boiler's electronic control panel is not communicating correctly with the main internal computer, which is preventing the system from running.

High Engineer only £150-300

Parts commonly replaced

  • User Interface (PCB)
  • Main Control Board (PCB)
  • Communication Wiring Harness

Related codes

Full explanation for 20
Showing 21–24 of 24
F1

Your boiler is failing to light the internal flame needed to produce heat or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Full explanation for F1
F4

Your boiler is trying to start but failing to light the flame, so it has shut down for safety to prevent gas from building up.

High Engineer only £120-250

Parts commonly replaced

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

Related codes

Full explanation for F4
Ignition fault

Your boiler has failed to light the flame needed for heating and hot water, so it has safely shut itself down.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Full explanation for Ignition fault
Water pressure

Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.

High DIY-safe £80-150

What to check first

  1. Locate the filling loop (a flexible metal hose) connected to the pipework underneath your boiler.
  2. Open the valves at both ends of the filling loop slowly to let water enter the system.
  3. Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically between 1.0 and 1.5 bar).
  4. Once the pressure is correct, firmly close both valves and ensure the loop is disconnected if it is a removable type.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure sensor
Full explanation for Water pressure