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5 Common Ferroli Boiler Fault Codes and How to Fix Them

If you’ve found us here, it’s because your Ferroli boiler is malfunctioning. To help you out, this guide will cover the most common Ferroli boiler faults codes (luckily, some Ferroli boiler problems have really easy fixes!).

And if your Ferroli boiler displays an error code we didn’t address, please leave a comment below and we’ll get back to you as soon as possible.

Ferroli Boiler Fault Codes

With any faults involving a boiler’s internal components, it’s important that you always consult a local Gas Safe engineer to fix the problem.

Rather ditch your old Ferroli boiler? We’d recommend heading over to Heatable. They are an online boiler installation company that focuses on technology rather than sales reps.
Meaning, you’ll be able to get a brand new Worcester boiler fitted for a ridiculously low price!

Short On Time? Ferroli Boiler Problems and Fault Codes Summary

If you know which problem or boiler error codes you’re dealing with, go ahead and jump right to your problem below:

  1. Ferroli boiler locking out
  2. Ignition issues with Ferroli boiler — fault codes A01 and A06
  3. Ferroli boiler pressure loss — fault codes A23 and A37
  4. Leaking Ferroli boiler keeps leaking
  5. Boiler switches on and off — Ferroli fault codes A34, A35, A36 and A62
  6. Ferroli combi boiler no hot water

Ferroli Boiler Keeps Locking Out

This is one of the most frustrating Ferroli boiler problems. It’s almost like the boiler wants to fire, then just stops working altogether. On some occasions, it might fire up for a split second and then lock out again.

There are various fail-safes in Ferroli boilers that will stop them from igniting and make them lock out. This is particularly common on the Modena and Optimax boilers.

Typically, this issue relates to a faulty Printed Circuit Board (PCB), which is the heart of the boiler.

Fixing Boiler Lockouts

You’ll have to get a Gas Safe engineer to run an electrical test using a multimeter. They’ll check to see if there are any breaks in the circuit. Hopefully, there is a small break in the circuit that can be easily re-wired, otherwise this fault may get incredibly expensive.

If the wiring is in good condition, you’ll probably need to install a new PCB. And this is rarely good news.

A quick search on Google will show the Ferroli Modena 80e PCB weighing in at over £300, and you can expect to pay £100-200 to have it fitted on top of that.

Like many PCB failures, the best option for an old Ferroli boiler (espcially one out of warranty) is to buy a replacement boiler. The cost of a PCB just isn’t worth the investment for old and unreliable boilers. You can get fixed price boiler quotes on screen (no obligation or personal details are needed) within 2 minutes using this clickable form from Heatable.

Note that boiler lockouts may stem from legitimate safety issues, too — after all a lockout is essentially a “protection activation” measure meant to safeguard you and your property from hazards. For example, a gas valve error can create a dangerous situation, so the boiler’s PCB responds to this threat by locking the boiler out altogether. A Gas Safe engineer will be able to pinpoint the exact issue and recommend a solution.

Ferroli Boiler Ignites, Then Turns Straight Off

Possible fault codes: A01 and A06

Ferroli boiler problemsThis Ferroli boiler fault is extremely common in the older Sigma models, such as the Sigma 50 and Sigma 60. After locking out, the boiler usually displays an A01 or A06 fault code.

If your boiler ignites for a second or two, or if it makes a blowing sound and then turns off, there is likely to be an issue with the flue.

Malfunctioning burner ignition can boil down to parts degrading over time, or blockages that cause your boiler to not vent gases correctly.

Ferroli A01 Fix 

If you’re in luck, the Ferroli A01 fix may end up being fast and simple. Start by checking that the flue is not being blocked; it’s not uncommon for leaves or debris to get blown into a flue, and this would stop it for venting correctly. Once you remove the debris, your boiler should ignite and work without further issues.

However, if the flue is clear of debris, it’s possible that your flue has corroded over time. In this case, a Gas Engineer will need to come and replace the flue and wall clamps. The cost of fixing this boiler fault can vary. The main difference in cost will come down to the type of flue you have.

For example, a horizontal flue will cost £30-50. A vertical flue will cost somewhere in the region of £90-120. If you need extensions, they are usually priced at £20-30 each. And then of course, there is the cost of labour.

All in all, an average flue replacement can set you back £140-200.

Ferroli Boiler Pressure Loss

Possible fault codes: A23 and A37

Some Ferroli boilers will lockout if the pressure gets too low. Topping up the boiler is a quick fix, but it certainly doesn’t solve the problem. To clear the Ferroli boiler fault codes A23 and A37, which relate to water pressure loss, you’ll need a permanent fix.

Leaks are the most common cause of any boiler losing system water pressure. Most of the time the leak will occur on radiator valves, or valves on towel rails.

However, the leak can sometimes come from the auto air vent in the boiler, or expansion vessel.

If the water pressure loss is not caused by a leak, air build-up in the radiators may be the culprit.

Fixing Water Pressure Loss and Lockouts

The easiest way to start is by checking for visible leaks. If the leak comes from a valve or stop tap, try tightening it slightly.

If there are no leaks, move onto the air in the radiators. You can use a radiator bleed key to remove the air. Close the vent when air stops coming out and water starts.

If neither of these issues solve the problem, there’s possibly a lack of pressure in the expansion vessel.

A Gas Engineer will come out and top up the pressure on the expansion vessel and ensure there are no other faults with your heating system. In this scenario, it’s worth considering a replacement expansion vessel.

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Ferroli Boiler Keeps Leaking

A lot of old Ferroli boiler faults come from malfunctioning shut valves in the boiler. A typical symptom is water pooling below the boiler’s casing.

There are other issues that may cause the boiler leak, though. We’ve fixed a Modena 80e in the past that had a loose pump; the pump started leaking and damaged many other internal parts.

Fixing a Leaky Boiler

If the problem is isolated to the shut valves on your Ferroli boiler, replacements will be in order — there’s rarely a way to fix shut valves without directly replacing them.

And if the fault relates to the pump, try tightening it to its housing. This usually fixes the issue. The only problem here is the seal may have experienced excess strain. If the pump is still functional, you can replace just the seal.

Ferroli Boiler Switches On/Off Without Warning

Possible fault codes: A34, A35, A36 and A62

It’s not just boilers that develop faults. A lot of the times when customers think it’s the boiler playing up, it’s the controls that are malfunctioning.

Before going through any expensive fixes, it’s a good idea to have a heating engineer check that all the controls are operational.

Ferroli boiler fault codes that relate to problems with electrical components include A34, A35, A36 and A62.

Fixing Problem Boilers

The most obvious fix here is the to replace the mechanical timer and thermostat.

Bear in mind, there are other reasons a boiler can behave in this manner. For example, there are various pressure and flame sensors in a boiler; if they become clogged with debris, they are no longer able to do their job. This could explain the erratic behaviour.

Ferroli Combi Boiler No Hot Water

Possible fault code: D1

Another one of the common Ferroli boiler problems is when your central heating works fine, but there’s no hot water in your taps. In most cases, this fault is caused by a diverter valve error — an important part that switches the boiler’s modes between heating system water circulation and domestic hot water. The Ferroli boiler D1 fault code typically means a problem with the diverter valve.

Fixing Ferroli Boiler Problems with No Hot Water

You may be lucky, and the diverter valve has simply seized in the central heating mode. In this case, a Gas Safe engineer shouldn’t take long to free the valve and get it working once again and clear the D1 error code.

However, if the diverter valve is old and worn out, you may need to get a replacement; expect this to cost around £350.

Other Ferroli Boiler Error Codes

Here are a few other Ferroli boiler error codes (and meanings) you should be aware of:

  • A02: flame signal present with burner off — an issue with the PCB or electrodes.
  • A05: fan error — fan may be damaged or out of balance or no 230V power supply.
  • A24: card parameter error — possible PCB issue.
  • F41: activation of maximum DELTA T protection — the heating sensor is damaged, return sensor is damaged, no water circulation in the system, or air in the system.
  • F10: delivery senor error — damaged sensor or wiring.
  • F11: return sensor fault — damaged sensor or wiring.

If you’re seeing any of these, please get a Gas Safe engineer or your boiler cover company to investigate the issue further.

Still Having Ferroli Boiler Problems?

If the recommended fixes about didn’t help and your old Ferroli boiler is beyond repair, it may be time to consider a replacement. We suggest you start by geting quotes for a new boiler online from Heatable. It’s fast, easy, and you’ll get the most competitive boiler installation prices on the market — backed by a generous 10-year warranty.

Ferroli Boiler Fault Codes: CONCLUSION

We hope that our guide to Ferroli boiler fault codes has helped you diagnose and fix the problem you’re experiencing. If your boiler shows an error code that we didn’t cover above, or you have any other questions, please leave a comment and we’ll get back to you as soon as possible.

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  1. Anthony Davis says:

    Ferroli f30 no pilot light

    1. heatingforce says:

      Hi Anthony,

      Any fault codes being displayed? Any other details?


      Try that, as without further details, it’s quite difficult to help out.


  2. karolis says:

    heello my ferroli boiler shows f 37 and no heating coming what should i do

    1. heatingforce says:

      What’s the pressure on the boiler? Is both heating/hot water no working, or just heating?

  3. Amanda Hall says:

    Hi, no fault showing on boiler, heating/water working. Woke up with water dripping from beneath the boiler, large puddle on floor.
    Pressure 1.

    1. heatingforce says:

      Hi Amanda,

      Get an engineer out, as only Gas Safe engineers should be removing boiler cases.

      It’s probably pump seals or a cracked heat exchanger.

  4. Jenny Nicholson says:

    Ferroli optimax HE plus 25s
    No fault showing ,boiler fires for 10 mins the shuts off,all disply showing just no flame
    Pressure bar fine
    ? Help with the problem
    Regards jen

    1. heatingforce says:

      Do the rads heat up?

      Has this always happened? If it has where is your thermostat located?

      Have the thermistors/pump been tested? Has the system every been flushed? Does it have a mag filter/scale reducer fitted?

  5. Angie Kenning says:

    My feroli central heating boiler makes terrible noises when first switched on and when switched off and sometimes in the middle of the night. My neighbours call it JAWS. What is the problem and can it be easily fixed. I.e won’t cost the earth.

    Hope you can help

    Thanks. Angie

    1. heatingforce says:

      Hey Angie. A quick write-up here on noisy boilers…https://heatingforce.co.uk/blog/noisy-boiler/

  6. Sarah green says:

    Hi my boiler is showing f5. I have replaced the air pressure switch but my hot water only runs hot for about a minute before going cold. Any ideas

    1. heatingforce says:

      The F5 fault varies depending on the Ferroli you have. Do you know what model it is? On most, it’s a fan/fan related fault. Get a boiler engineer to come and check the fan, as well as wiring/connections to/from the PCB.

  7. Unknown says:

    My boiler turns on itself even when centre heat not on .. it turns on for few seconds and turns off itself .

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