Ideal FH fault code on boiler

Your Ideal boiler’s display screen may be showing an alternating F or H. This is an indication that something has gone wrong internally and it must be fixed before it can start working again.

Although you may be able to solve the problem at home, legal work on the boiler must be done by an engineer registered with Gas Safe.

This guide will explain the Ideal FH error code to get your hot water and central heating back up and running. If you have an old boiler, however, say over 10 years old, it may be time to invest in a new boiler as issues can start to mount up.

What does the FH Error code mean?

Ideal describes the code’s simplified meaning as “Flame detection error”. This indicates that your boiler cannot confirm whether it has lit the required flame to produce heat.

The boiler’s control unit contains a printed circuit board (PCB), which acts as a hub for all the components.

If the PCB cannot verify that every step of the process to produce heat took place, it will cause short circuits, which will stop the boiler from operating.

FH fault on the boiler display is a safety precaution to prevent gas from escaping without a flame being lit. This could cause a dangerous explosion or leakage. All fault codes are there for your protection and to help diagnostics.

What causes the FH Error code?

Ideal suggests that either the flame detection electrode, or the PCB is likely to be the cause of the FH error. This is a relatively common fault, however, there are other possible causes.

You may be able to solve the flame detection error yourself in some cases, but most likely an engineer is required.

The Boiler’s Flame Detection Electrode is Dirty

This is the boiler’s component that detects if a flame has been lit. It may also be called its flame sensor.

This electrode can block over time from prolonged exposure to open flame.

The most common cause is carbon deposits, but dust and other particles could also cause sensor failure. It may also rust due to small amounts of water vapour in the boiler.

What to do if the Boiler’s Flame Detection Electrode is Dirty

An engineer can remove the electrode and clean it with emery cloth.

If the electrode is in good condition after cleaning, the boiler will return to normal operation and they won’t need to replace it.

This should be part of your boiler’s regular maintenance.

The Boiler’s Flame Detection Electrode is Damaged

It is possible for the electrode to have been scratched if it has been previously cleaned with too abrasive material such as sandpaper.

The electrode is more vulnerable to failure if it has been scratched.

The electrode is typically insulated with porcelain. Over time, this can crack or break.

What to do if the boiler’s flame detection electrode is damaged

If an engineer can see damage to the electrode or casing, they will replace it. It is possible that the engineer may not need to replace the part if it is not clear. The boilers that use this error code require flame detection electrodes. They cost between £25 to £35

Faulty PCB (Printed circuit board)

If the flame sensing electrode works, it could be that the PCB’s corresponding terminal is not working correctly.

All processes pass through the PCB. Any failure will affect the boiler’s operation in turn.

How to fix a faulty PCB

After the electrode is serviced, any damage to the PCB or wiring will be checked.

It’s the most costly part of Ideal boilers, so a new PCB can run up to £300. However, engineers often are able to order them at a lower price.

The Boiler Isn’t Receiving Enough Fuel

This code can appear if there’s a flame, but it is not being detected. However, it can also appear if something is stopping the flame from reaching the required strength for the sensor.

If your gas supply is cut off or your pre-paid gas meters aren’t charged up, this is likely to happen.

You could also find that your gas has been connected but the pressure reaching the boiler is too low to allow it to run.

The Boiler Isn’t Receiving Enough Fuel

An engineer can assist you if the interruption in gas supply is not due to a payment problem. If you’ve checked the valves and they appear to have been turned on, or you are unable locate them, then an engineer can help.

They will be able service both the mains supply valves and those controlling the flow into the boiler.

Low gas pressure can lead to a variety of solutions, depending on the reason. Insulating an outdoor gas meter is one solution. This would help in cases where cold weather has caused it frost and produced incorrect readings.

Frozen Condensate Pipe

This is not directly related to the flame sensing electro, but it is a common problem that causes boiler error codes, especially in winter.

Therefore, it makes sense to account the problem if the fault code appears during cold weather. This is a relatively simple problem to fix.

Condensing technology is required for all boilers in the UK installed after 2005. This increases energy efficiency.

This ensures that harmful exhaust gases generated during heating are not lost as the unit extracts the water vapour from them and re-uses them to heat more water.

This process produces acidic wastewater that must be safely removed from your home. The “condensate pipeline”, made of plastic, runs from your boiler to your exterior.

It’s open to the air at its exit point so it can get blocked by ice in cold weather.

Your boiler’s safe operation is dependent on the efficient removal of wastewater. If it senses that it has blocked this path, it will stop working.

Can I fix my own Ideal boiler with the FH Error code?

This code will likely indicate a problem within the boiler unit. In most cases, you’ll need to contact a Gas Safe registered engineer.

You can take a few steps before you do so. These are not necessary to interfere with your boiler’s internal processes.

Boiler not receiving enough gas

  • Your pre-paid gas meter can be topped up
  • To confirm that your gas supply is not being cut due to non-payment, or local works, contact your gas supplier
    Make sure the valve that controls the mains gas supply is in the same plane as the pipe. If the valve is perpendicular, it means that the gas supply has been cut off.
  • If you see the valve controlling the gas supply to your boiler from outside, make sure it is parallel to the pipe.
  • Verify that other gas-fuelled appliances work.

Condensate Pipe Frozen

  • Locate the exit point for the pipe from your property’s exterior. These pipes are often installed in a sharp diagonal angle to drains.
  • If the pipe feels extremely cold, then it may have icy blockages.
  • Warm water can be used to warm the pipe or a hot water bottle to reduce spillage and keep it safe
  • Use boiling water to avoid causing damage to the pipe’s plastic.

When do I need to call an engineer for the FH Error code?

A Gas Safe engineer will be required to diagnose and fix the problem in the following situations.

This service may be available if your boiler is still under warranty. If not, you might need to pay additional labour costs for the replacement of parts.

Which Ideal Models Use the FH Error code?

Ideal’s newer models are less likely not to use this code. If the fault is occurring, it is likely that your boiler was installed in the early or mid 2000s.

These are just a few examples of models that might display the FH error code.

  • Ideal Icos HE12
  • Ideal Icos HE15
  • Ideal Icos HE18
  • Ideal Icos HE24
  • Ideal Isar HE24
  • Ideal Isar HE30
  • Ideal Isar HE35
  • Ideal Istor HE260
  • Ideal Istor HE325
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