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Ideal Isar HE30 Fault Codes – Error Code Guide

The Isar range of combi boilers was created by Ideal Heating in order to meet demand for the UK government’s Warm Front Scheme, which ran between 2000 and 2013.

If your Ideal Isar HE30 has begun to display fault codes you may be due for repairs or replacing with a more reliable model, which legally must be undertaken by a registered Gas Safe engineer.

The codes will alternate on your display, meaning that what Ideal calls L-F will show as a flashing ‘L’ then a flashing ‘F’.

This means it could also be read as F-L. We have followed Ideal’s lead in this guide, so if you can’t find the code you’re seeing, try reversing the letters.

This guide will help you to determine what your next steps are, depending on the error code your boiler is displaying.

 

L-F Fault Code

What it means

Flame detection error or failure to ignite. This is commonly caused by gas supply issues, dirty components such as the spark electrode, ionisation probe, or a frozen condensate pipe.

What you can try at home

  • Hold down the button marked “reset” for two seconds, which will cause the boiler to attempt to reignite.
  • Ensure that your gas meter is topped up
  • Check that your gas supply is switched on and other appliances connected to it are working
  • Ensure that the condensate pipe is not frozen where it exits your home, gently pour hot but not boiling water over the area to defrost

When you’ll need to call an engineer

  • Resetting doesn’t work, or it does but the fault continues intermittently
  • Any of the internal components need cleaning or replacing

L-E / H-E Fault Code

What it means

PCB Error. PCB stands for Printed Circuit Board, which is part of your boiler where all electrical components meet. Any issue with the PCB prevents the boiler from running through each of the steps needed to produce heat.

What you can try at home

  • Hold down the button marked “reset” for two seconds
  • Turn the boiler off at the plug, then turn back on again and attempt to reset

When you’ll need to call an engineer

  • Resetting at the boiler or electricity supply doesn’t work
  • The PCB needs to be replaced
  • A fault with another part of the boiler is affecting the PCB

L-A Fault Code

What it means

Overheat error. This can be caused by water pressure issues, a faulty overheat thermostat, or problems with the system pump that lead to a leak.

What you can try at home

  • Check the boiler’s water pressure gauge has not dropped below 1 bar. If your boiler has a filling loop attached, you can open this to repressurise the boiler until the gauge shows reaches between 1 and 2 bar. 1.2-1.5 is recommended
  • Bleed any radiators that require it, which will usually be the case if the bottom half heats up but the top remains cold
  • Hold down the button marked “reset” for two seconds

When you’ll need to call an engineer

  • Your boiler doesn’t have a filling loop attached, so you are unable to repressurise it yourself
  • The pressure continues to drop despite repressurising
  • There is a leak, which could come from the pipe leading to the outside, or it may be elsewhere in your central heating

L-8 Fault Code

What it means

Fan error. The fan in your boiler pushes harmful gases that are produced in the heating process away from your home. The unit itself can become faulty, but the error can also be caused by PCB issues or blockages to the airflow. Most of these issues can only be diagnosed by an engineer as they are inside the unit.

What you can try at home

  • Hold down the button marked “reset” for two seconds

When you’ll need to call an engineer

  • Resetting doesn’t work, or it does but the fault continues intermittently
  • The fan’s speed needs to be adjusted
  • An electrical issue such as damaged connections or a faulty PCB needs to be fixed
  • The condensate pipe or flue need to be unblocked
  • The fan unit needs to be totally replaced, which may be the case if your boiler is over 5 years old

H-1, H-2, or H-3 Fault Code

What it means

These three codes are related to problems with the boiler’s external thermistors. Each code refers to a different thermistor, and indicates the pipe where the part is located:

  • H-1: Flow thermistor error
  • H-2: Return thermistor error
  • H-3: DHW (Domestic Hot Water) thermistor error

The thermistor is an electrical component which helps to control the temperature in your boiler, forming part of the circuit between the temperature control dial and the internal printed circuit board (PCB).

These faults can be caused by a degraded part, damage to wiring, or a faulty PCB. 

What you can try at home

  • Hold down the button marked “reset” for two seconds

When you’ll need to call an engineer

  • Any thermistor part needs to be replaced
  • Rewiring is needed between the thermistor and PCB
  • The PCB needs to be replaced

H-4 Fault Code

What it means

Dry fire thermistor error. A thermistor (thermal/resistor) is an electrical component which helps to control the temperature in your boiler, forming part of the circuit between the temperature control dial and the internal printed circuit board (PCB).

The dry fire thermistor is located within the unit, rather than on the external pipes. Common causes of this fault code are damage to the internal wiring, the part itself, or its corresponding terminal on the PCB.

What you can try at home

  • Turn the boiler off at the plug or mains supply, then turn back on again

When you’ll need to call an engineer

  • Resetting at the electricity supply doesn’t work
  • The dry fire thermistor or PCB need to be replaced
  • Internal wiring needs to be checked and/or replaced

H-F Fault Code

What it means

Flame detection error. This can be caused by a fault with the electrode which detects whether a flame is present, or its corresponding terminal on the PCB.

If the PCB is unable to confirm that a flame has been lit, it will shut down the system in order to avoid dangers such as gas leaks.

What you can try at home

  • Turn the boiler off at the plug or mains supply, then turn back on again. Resetting at the boiler alone is unlikely to work in this instance

When you’ll need to call an engineer

  • The flame detection electrode needs to be replaced
  • The PCB terminal is faulty, requiring a replacement of the PCB

H-n Fault Code

What it means

Phase reversal error. This appears when live and neutral wiring has not been linked up correctly, either at the boiler itself or somewhere else in the house’s electricity supply. While a boiler may have worked up to this point, it can be dangerous to have incorrectly wired appliances in your home, so it must be fixed once this error is identified.

What you can try at home

  • Note if you have had other issues with your electricity recently, or had any work done in the house. If that’s the case, you could contact the people who carried out the work first in case they have caused an electrical fault elsewhere

When you’ll need to call an engineer

  • The wiring to the boiler needs to be inspected for a reversal of live and neutral wires
  • The system needs to be rewired, which may require an electrician depending on where the wiring fault has occurred

H9 or L9 Fault Code

Heat exchanger overheat. The heat exchanger is the part which allows heat to travel between the water and gas in your boiler, without the two mixing. The part can become blocked or damaged, leading to this fault. It can also be caused by water pressure issues, problems with the dry fire thermistor, or a faulty system pump.

What you can try at home

  • Check the boiler’s water pressure gauge has not dropped below 1 bar. If your boiler has a filling loop attached, you can open this to repressurise the boiler until the gauge shows reaches between 1 and 2 bar. 1.2-1.5 is recommended
  • Bleed any radiators that require it, which will usually be the case if the bottom half heats up but the top remains cold
  • Hold down the button marked “reset” for two seconds

When you’ll need to call an engineer

  • Your boiler doesn’t have a filling loop attached, so you are unable to repressurise it yourself
  • The pressure continues to drop despite repressurising
  • The heat exchanger has become blocked or damaged, and requires cleaning or replacement
  • The dry fire thermistor needs to be replaced

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