BoilerFaultCodes E00
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Warmflow Agentis External Fault codes & diagnostics
15 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
CombiSystemHeat Only Oil 2018-present
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Severity at a glance
Each cell = one fault code. Hover to identify. 1 Emergency
11 High
2 Medium
1 Unrated
Just want the most common Warmflow Agentis External faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 15 documented codes
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E01 Your boiler's burner has shut down because it cannot light the fuel, likely due to an empty oil tank or a blockage in the supply line.
Your boiler's burner has shut down because it cannot light the fuel, likely due to an empty oil tank or a blockage in the supply line.
What to check first
- Check your oil tank level to ensure you have not run out of fuel.
- Inspect the oil supply valves to ensure they are fully open.
- Locate and press the illuminated reset button on the burner unit within the external cabinet.
Parts commonly replaced
- Oil pump
- Photocell
- Oil nozzle
- Fuel filter
Related codes
E02 Your boiler has switched itself off because it has detected that the water inside has become too hot.
Your boiler has switched itself off because it has detected that the water inside has become too hot.
Parts commonly replaced
- Overheat Thermostat
- Circulation Pump
- Thermistor
Related codes
E04 Your boiler has detected that the water pressure is too low for it to operate safely, which often happens after bleeding radiators or if there is a small leak.
Your boiler has detected that the water pressure is too low for it to operate safely, which often happens after bleeding radiators or if there is a small leak.
What to check first
- Locate the filling loop (the flexible silver hose) underneath or near the boiler.
- Slowly open the valve(s) until you hear water flowing and the pressure gauge rises to between 1.0 and 1.5 bar.
- Close the valve(s) tightly and restart the boiler to clear the fault.
Parts commonly replaced
- Expansion vessel
- Pressure relief valve
- Automatic air vent
Related codes
E05 Your boiler has lost connection with a internal temperature sensor, meaning it cannot safely tell how hot the water is and has shut down as a precaution.
Your boiler has lost connection with a internal temperature sensor, meaning it cannot safely tell how hot the water is and has shut down as a precaution.
Parts commonly replaced
- Flow NTC Temperature Sensor
- Sensor Wiring Harness
Related codes
E06 Your boiler has detected a problem with the sensor that monitors the temperature of your hot water, meaning the system cannot safely heat water for your taps.
Your boiler has detected a problem with the sensor that monitors the temperature of your hot water, meaning the system cannot safely heat water for your taps.
Parts commonly replaced
- DHW Flow NTC Sensor
- Wiring harness connector
Related codes
E11 Your boiler's internal temperature sensor has slipped out of its correct position or is sending an unusual reading, meaning the system cannot safely monitor the water tank temperature.
Your boiler's internal temperature sensor has slipped out of its correct position or is sending an unusual reading, meaning the system cannot safely monitor the water tank temperature.
Parts commonly replaced
- NTC Temperature Sensor Probe
- Sensor Retaining clip
Related codes
E12 Your boiler has lost communication with the temperature sensor that monitors your hot water tank, meaning it cannot safely heat your water.
Your boiler has lost communication with the temperature sensor that monitors your hot water tank, meaning it cannot safely heat your water.
Parts commonly replaced
- Tank Control NTC Sensor
- Sensor Wiring Harness
Related codes
E15 Your boiler's internal sensor that monitors the water returning from your radiators has developed a fault or become disconnected.
Your boiler's internal sensor that monitors the water returning from your radiators has developed a fault or become disconnected.
Parts commonly replaced
- CH Return NTC Thermistor
- Sensor Wiring Harness
Related codes
E22 Your boiler's internal computer brain has suffered a memory error and can no longer process instructions safely.
Your boiler's internal computer brain has suffered a memory error and can no longer process instructions safely.
Parts commonly replaced
- Main PCB (Printed Circuit Board)
Related codes
E31 Your boiler has lost its connection to the external control panel, meaning it cannot receive the signals it needs to turn on or off.
Your boiler has lost its connection to the external control panel, meaning it cannot receive the signals it needs to turn on or off.
Parts commonly replaced
- Remote control wiring
- Digital control interface
- Main PCB
Related codes
E32 Your boiler's main control panel is having trouble communicating with the internal computer, likely due to a wiring issue or a faulty circuit board.
Your boiler's main control panel is having trouble communicating with the internal computer, likely due to a wiring issue or a faulty circuit board.
Parts commonly replaced
- Main Control PCB
- MMI Display Unit
- Communication Cable
Related codes
E46 Your boiler has lost its connection to the sensor that monitors water pressure, meaning it cannot confirm if it is safe to operate.
Your boiler has lost its connection to the sensor that monitors water pressure, meaning it cannot confirm if it is safe to operate.
Parts commonly replaced
- Water pressure sensor
- Wiring harness
- Main PCB
Related codes
E48 Your boiler has detected too much water pressure in the system, which can cause the safety valve to leak if left unaddressed.
Your boiler has detected too much water pressure in the system, which can cause the safety valve to leak if left unaddressed.
What to check first
- Check that the silver braided filling loop valves are tightly closed.
- Locate a radiator and use a bleed key to release water into a cloth until the pressure gauge drops to 1.5 bar.
- Reset the boiler to clear the fault code.
Parts commonly replaced
- Filling loop valve
- Expansion vessel
- Pressure relief valve
Related codes
E62 Your boiler's main internal computer and the display panel are having trouble communicating, which has caused the system to stop working for safety.
Your boiler's main internal computer and the display panel are having trouble communicating, which has caused the system to stop working for safety.
Parts commonly replaced
- Main Control PCB
- MMI Display Board
- PCB Wiring Harness
Related codes
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