Ariston Genus HE Fault codes & diagnostics

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

Combi Natural Gas 2007-2013 Discontinued
GC Numbers 47-116-5447-116-5547-116-56
Download the Ariston Genus HE 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.
1 Emergency 27 High 10 Medium 3 Low
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
47-116-54 Genus HE 24 2007–2013
47-116-55 Genus HE 30 2007–2013
47-116-56 Genus HE 38 2007–2013
Just want the most common Ariston Genus HE faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 41 documented codes

Tap any card for details

1 01

Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.

High DIY-safe £100-350

What to check first

  1. Wait for the boiler to cool down for 30 minutes
  2. Press the 'Reset' button on the front panel
  3. Ensure all radiator valves are fully open and the system pressure is between 1 and 1.5 bar

Parts commonly replaced

  • Circulation pump
  • Overheat thermostat
  • Main heat exchanger

Related codes

Full explanation for 1 01
1 02

The boiler's internal computer is receiving incorrect or missing information regarding the system's water pressure, preventing it from running safely.

High Engineer only £140-£240

Parts commonly replaced

  • Water Pressure Sensor
  • Wiring Harness
  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 1 02
1 03

Your boiler has detected that water is heating up too quickly because it isn't circulating through the system properly, causing it to shut down for safety.

High DIY-safe £100-£350

What to check first

  1. Check that your boiler pressure is between 1.0 and 1.5 bar
  2. Ensure all radiator valves (TRVs) are turned to their highest setting
  3. Check that the isolation valves under the boiler are fully open

Parts commonly replaced

  • Central heating pump
  • Main heat exchanger (de-scaling)
  • Flow/Return thermistors

Related codes

Full explanation for 1 03
1 04

Your boiler is heating up too quickly because water isn't moving through the system fast enough, causing it to shut down to prevent overheating.

High DIY-safe £120-£350

What to check first

  1. Check that your boiler pressure is between 1 and 1.5 bar on the gauge
  2. Ensure all radiator valves are fully open
  3. Bleed your radiators to remove trapped air from the system
  4. Reset the boiler using the 'Reset' button

Parts commonly replaced

  • Central heating pump
  • Main heat exchanger
  • Return filter
  • Flow/Return thermistors

Related codes

Full explanation for 1 04
1 05

Your boiler has detected that water is it not moving through the system quickly enough, causing it to overheat and shut down for safety.

High DIY-safe £120-£350

What to check first

  1. Check that at least two or three radiator valves (TRVs) are turned to the maximum setting.
  2. Ensure the boiler pressure gauge is between 1 and 1.5 bar.
  3. Bleed all radiators to remove any trapped air pockets.

Parts commonly replaced

  • Circulation Pump
  • Main Heat Exchanger (Cleaning/Descaling)
  • Flow/Return Temperature Sensors

Related codes

Full explanation for 1 05
1 06

Your boiler has detected that water is returning to the unit hotter than it was sent out, which usually means the water isn't moving through your radiators properly.

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 on the gauge.
  3. Bleed all radiators to remove trapped air which may be blocking flow.

Parts commonly replaced

  • Circulation Pump
  • Return Temperature Sensor (NTC)
  • Main Heat Exchanger (if blocked)

Related codes

Full explanation for 1 06
1 07

Your boiler has sensed that heat is not moving away from the unit quickly enough, causing the temperature to rise too fast and triggering a safety shutdown.

High DIY-safe £120-350

What to check first

  1. Check that at least two or three radiators have their valves turned fully open.
  2. Ensure the central heating system pressure is between 1.0 and 1.5 bar on the gauge.
  3. Bleed all radiators to remove trapped air pockets that might be blocking water flow.

Parts commonly replaced

  • Central heating pump
  • Main heat exchanger (cleaning or replacement)
  • Temperature sensors (NTC thermistors)

Related codes

Full explanation for 1 07
1 08

Your boiler has lost water pressure, which means there isn't enough water inside the system for it to operate safely and effectively.

High DIY-safe £0-160

What to check first

  1. Locate the filling loop (usually a silver flexible hose) underneath the boiler.
  2. Slowly open the small valve(s) until you hear water flowing and watch the pressure gauge.
  3. Close the valves tightly once the pressure gauge reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for 1 08
1 10

Your boiler has detected a problem with the sensor that monitors the temperature of the water leaving the unit, causing it to shut down as a safety precaution.

High Engineer only £90-160

Parts commonly replaced

  • Central Heating Flow NTC Thermistor
  • Connecting wiring harness

Related codes

Full explanation for 1 10
1 12

Your boiler has stopped working because it cannot correctly measure the temperature of the water returning from your radiators.

High Engineer only £90-160

Parts commonly replaced

  • Return NTC thermistor (temperature probe)
  • Wiring harness connector

Related codes

Full explanation for 1 12
Showing 11–20 of 41
1 14

Your boiler has lost connection with the sensor that measures the temperature outside, which may cause your heating to behave unpredictably.

Low Engineer only £90-160

Parts commonly replaced

  • External temperature sensor (Outdoor probe)
  • Wiring harness

Related codes

Full explanation for 1 14
1 16

Your boiler has detected that the safety sensor for your underfloor heating system has tripped to prevent overheating.

Medium Engineer only £90-180

Parts commonly replaced

  • Overheat thermostat
  • Wiring harness
  • Circulation pump

Related codes

Full explanation for 1 16
1 18

Your boiler has detected an issue with the sensor that monitors the temperature of the water being sent to your radiators, which prevents it from heating your home correctly.

High Engineer only £90-160

Parts commonly replaced

  • Flow NTC Temperature Sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for 1 18
1 P1

Your boiler is struggling to move water through the system effectively, which is causing it to stop running to prevent overheating.

High DIY-safe £100-£280

What to check first

  1. Check that your system pressure is between 1 and 1.5 bar on the pressure gauge.
  2. Ensure all radiator valves are fully open to allow water to flow.
  3. Gently bleed your radiators to remove any trapped air pockets.

Parts commonly replaced

  • Circulation Pump
  • Main Heat Exchanger (Descaling)
  • System Filter

Related codes

Full explanation for 1 P1
1 P2

Your boiler is struggling to move water through the system properly, which is causing it to stop running to prevent overheating.

High DIY-safe £100-£350

What to check first

  1. Check that your boiler pressure is between 1 and 1.5 bar on the pressure gauge.
  2. Ensure all radiator valves (TRVs) are fully open to allow water to flow.
  3. Bleed your radiators to remove trapped air that could be blocking circulation.

Parts commonly replaced

  • Central heating pump
  • Main heat exchanger
  • Circulation sensor

Related codes

Full explanation for 1 P2
1 P3

Your boiler is struggling to move water through the system properly, which is preventing it from heating up correctly.

High DIY-safe £120-280

What to check first

  1. Check that the boiler pressure is between 1 and 1.5 bar on the gauge
  2. Ensure all radiator valves and the boiler isolation valves are fully open
  3. Bleed your radiators to remove any trapped air pockets
  4. Reset the boiler to see if the circulation clears

Parts commonly replaced

  • Circulation pump
  • Central heating filter
  • Main heat exchanger

Related codes

Full explanation for 1 P3
2 01

Your boiler's hot water sensor has failed or has a wiring issue, meaning it cannot accurately measure the temperature of the water coming out of your taps.

High Engineer only £90-160

Parts commonly replaced

  • DHW NTC thermistor (temperature probe)
  • Wiring harness connecting to sensor

Related codes

Full explanation for 2 01
2 02

Your boiler's hot water storage tank sensor has developed a fault and can no longer tell how hot the water is.

Medium Engineer only £90-160

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring Harness

Related codes

Full explanation for 2 02
2 04

Your boiler's solar heating sensor is reporting an electrical fault, meaning it cannot properly monitor the temperature of your solar panels.

Low Engineer only £90-160

Parts commonly replaced

  • Solar collector NTC sensor
  • Wiring harness

Related codes

Full explanation for 2 04
2 07

Your solar heating system has become too hot, causing the boiler to stop its solar energy collection to protect the system components.

Medium Engineer only £120-350

Parts commonly replaced

  • Solar circulation pump
  • Solar fluid/antifreeze
  • Temperature sensor (NTC)
  • Expansion vessel

Related codes

Full explanation for 2 07
Showing 21–30 of 41
2 08

Your boiler has detected that the solar collector on your roof is at risk of freezing and is running its protection cycle to prevent damage.

Low DIY-safe £0-120

What to check first

  1. Check that the solar fluid levels are adequate in the system gauge
  2. Ensure the solar pump station is powered on
  3. Monitor the display; this code usually clears automatically once the fluid has circulated or the temperature rises

Parts commonly replaced

  • Solar glycol fluid
  • Solar temperature sensor (NTC)

Related codes

Full explanation for 2 08
3 01

Your boiler's computer memory has developed a communication fault and can no longer process its operating instructions.

High Engineer only £220-450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Display PCB

Related codes

Full explanation for 3 01
3 02

Your boiler's internal components are having trouble speaking to each other or the display screen, causing the system to stop working.

High Engineer only £120-450

Parts commonly replaced

  • Main PCB
  • Display Interface Board
  • Wiring Harness

Related codes

Full explanation for 3 02
3 03

Your boiler's main control board has developed an internal electrical fault, preventing the system from operating correctly.

High Engineer only £250-£450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Internal Wiring Harness

Related codes

Full explanation for 3 03
3 04

Your boiler has been manually reset too many times in a short period, so it has locked itself out to prevent potential damage.

Medium Engineer only £100-200

Parts commonly replaced

  • Main PCB

Related codes

Full explanation for 3 04
3 05

Your boiler's internal computer is experiencing a communication or processing error, preventing the system from operating correctly.

High Engineer only £250-450

Parts commonly replaced

  • Main PCB
  • Wiring harness

Related codes

Full explanation for 3 05
3 06

Your boiler has detected an internal communication error with its main control computer, preventing it from operating safely.

High Engineer only £250-450

Parts commonly replaced

  • Main PCB
  • Wiring harness

Related codes

Full explanation for 3 06
3 07

Your boiler's central control computer is experiencing an internal electronic fault and has stopped working to prevent further damage.

High Engineer only £250-450

Parts commonly replaced

  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for 3 07
4 07

Your boiler is struggling to read the temperature of your home because the connection to your room thermostat has been lost or interrupted.

Medium Engineer only £120-200

Parts commonly replaced

  • Room thermostat
  • External sensor wiring
  • PCB interface module

Related codes

Full explanation for 4 07
5 01

Your boiler is attempting to start, but it cannot detect a flame, meaning your heating and hot water will not work.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Full explanation for 5 01
Showing 31–40 of 41
5 02

Your boiler has detected a flame when it should be turned off, which suggests a potential issue with the internal components that control the gas supply.

Emergency Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Main PCB

Related codes

Full explanation for 5 02
5 04

Your boiler is struggling to keep the flame stable during ignition, causing it to lift away from the burner and cut out for safety.

High Engineer only £150-300

Parts commonly replaced

  • Gas valve
  • Burner assembly
  • Air pressure switch
  • Venturi

Related codes

Full explanation for 5 04
6 04

Your boiler is failing to start because the internal fan that clears out exhaust gases is not spinning fast enough to allow the boiler to operate safely.

High Engineer only £180-350

Parts commonly replaced

  • Flue fan assembly
  • PCB
  • Fan harness wiring

Related codes

Full explanation for 6 04
6 10

Your boiler has detected a safety-related electrical circuit break, likely due to an internal overheating protection device that has tripped to prevent damage.

High Engineer only £150-250

Parts commonly replaced

  • Thermal fuse
  • Wiring harness
  • Main PCB

Related codes

Full explanation for 6 10
7 01

Your boiler is struggling to accurately measure the temperature of the water flowing to your radiators, which may cause your heating system to work incorrectly or turn off.

Medium Engineer only £120-200

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness

Related codes

Full explanation for 7 01
7 02

Your boiler is struggling to accurately read the temperature of the water returning from your radiators, which may stop your heating from working correctly.

Medium Engineer only £120-200

Parts commonly replaced

  • Return temperature sensor (NTC)
  • Wiring harness

Related codes

Full explanation for 7 02
7 03

Your boiler is having trouble reading the temperature for one of your heating zones, which may stop that specific area of your home from heating up correctly.

Medium Engineer only £120-220

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness

Related codes

Full explanation for 7 03
7 04

Your boiler is having trouble reading the temperature in one of your heating zones, which means it may not be heating that specific part of your home correctly.

Medium Engineer only £120-220

Parts commonly replaced

  • NTC temperature sensor
  • Wiring harness

Related codes

Full explanation for 7 04
7 05

Your boiler is struggling to accurately detect the flow of water through its internal system, which is preventing it from heating your home or water reliably.

High Engineer only £150-250

Parts commonly replaced

  • Hydraulic sensor
  • Wiring harness

Related codes

Full explanation for 7 05
7 06

Your boiler has detected that the water temperature in your main heating circuit has climbed too high, causing it to shut down to prevent damage.

High Engineer only £120-250

Parts commonly replaced

  • NTC sensor
  • Primary heat exchanger
  • Circulation pump

Related codes

Full explanation for 7 06
Showing 41–41 of 41
7 07

Your boiler has detected that the water temperature in one of your heating circuits is running too hot, causing the system to shut down for safety.

Medium Engineer only £120-250

Parts commonly replaced

  • NTC temperature sensor
  • Zone valve
  • PCB

Related codes

Full explanation for 7 07