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Biasi Boiler FL Fault Code


The Biasi fault code FL relates to the pressur ebeing too high which we include Q & A or require an engineer for an emergency boiler repair.


The Biasi Fault Code FL Error Common Q & A


Just below, we have a list of common questions relating to the FL fault code on the Biasi Boiler.

Biasi Boiler FL Fault Code Error
  • What does the FL fault code mean on my Biasi boiler?
  • Will resetting my boiler fix the problem causing the FL fault code to be displayed?
  • Is there a quick DIY fix to clear the FL fault code from the display panel?
  • When looking for a leak in a heating system, where should my boiler repair company start?
  • What parts in my Biasi boiler are most likely to leak?
  • Why would the heat exchanger be leaking?
  • If the pump is leaking, what would have been the cause?
  • Can my pump be fixed if it’s leaking?
  • How can heating sludge and limescale be removed from the system?
  • My system is clear, how do I increase the pressure on my boiler?
  • When topping up my boiler’s pressure, what pressure should I be aiming for?
  • My boiler pressure is too high, what can I do to get it back to 1.3 bar?
  • How do I remove water from my radiators?
  • If my system was leaking, what other problems could it have caused?

What does the FL fault code mean on my Biasi boiler


If you’ve noticed your Biasi boiler acting strangely of late, you’ll notice a fault code on the display panel. One of the most common faults we come across, is the FL error code; you’ll notice it flashing every couple of seconds.

If the FL error code is flashing on your Biasi boiler, it’s the boiler suggesting the boiler pressure isn’t high enough.

Will resetting my boiler fix the problem causing the FL fault code to be displayed


The value shown on the pressure gauge is directly linked to how much water is in the system. In order to increase pressure, you’ll need to increase the amount of water.

Therefore, resetting your boiler isn’t going to fix the problem. In fact, resetting the boiler could lead to more costly repairs.

It’s likely that your boiler’s printed circuit board (PCB) has recognised that there’s a problem and locked out the boiler; it won’t work until it’s been repaired and then reset. The lockout in this this case, is designed to protect expensive internal components. Continued operation with a low pressure system could put excess strain on the likes of the central heating pump.

Is there a quick DIY fix to clear the FL fault code from the display panel


The boiler’s pressure can be topped up via the external filling loop. But, before topping up the pressure, you need to ensure that whatever has caused the issue is seen to first.

Typically, we find a drop in heating system pressure, is most likely to be a leak. This leak could be causing damage to your boiler internals, or even flooring, depending on where it is.

If you suspect that the leak is coming from your boiler, you’ll need to call a Gas Safe engineer. It’s only these engineers that are qualified to work on gas appliances.

When looking for a leak in a heating system, where should my boiler repair company start


Your boiler repair company should start with a quick visual inspection of the heating system. Can they see any radiator valves leaking, or weak copper joints? If so, these are going to need to be replaced or repaired.

More importantly, they’ll want to quickly inspect the boiler to ensure there are no leaks. Even if there’s no water pooling below the boiler, there still could be a small internal leak.

What parts in my Biasi boiler are most likely to leak


There are two parts that are liable to leak in your boiler, the heat exchanger, and the pump.

Why would the heat exchanger be leaking


The heat exchanger is an integral part of your boiler, transferring heat energy from the burner, into heat in water. One problem the heat exchanger can suffer from (besides old age), are small blockages. Typically, these blockages come from limescale that’s got into the system; this is common in hard water areas.

Limescale enters the system via water. As it circulates, eventually it starts to settle on heating components such as the heat exchanger. Where limescale settles, the heat exchanger burns hotter. This increased temperature can lead to a weak spot in the heat exchanger, and eventually a crack.

When a heat exchanger develops a crack, it’s going to need to be replaced; expect to pay £450 or more for a heat exchanger replacement.

And of course, the most important problem here, is the leak; a leaking heat exchanger can cause damage to other important components in the boiler, so needs to be fixed as soon as possible.

If the pump is leaking, what would have been the cause


Like the heat exchanger, the pump can start leaking due to old age. However, it’s much more likely that there’s been a catalyst that’s caused the heat exchanger to start leaking, well before it should.

Blockages are a major killer of boiler parts, including the heating pump. Rather than limescale being the issue, it’s likely that the problem here is heating sludge; rust that’s made its way into the heating water.

Can my pump be fixed if it’s leaking


There’s a good chance your boiler repair company can find seals to recondition your pump. However, if the pump’s overall condition isn’t good, a replacement is likely to be the best option.

Expect to pay around £250 for a replacement pump from a quality brand such as Grundfos.

How can heating sludge and limescale be removed from the system


The first thing to do, is to clear major blockages manually. After this, using a specifically designed heating system cleaning chemical is going to remove most of the heating sludge and limescale from your system, this is known as a central heating power flush.

Long term, it’s likely that the limescale and heating sludge will continue to build-up in the system, so you’ll need something to combat that. For those in hard water areas, we suggest adding a limescale filter. And for those struggling with heating sludge, we’d suggest adding a magnetic system filter. Each of these filters will catch debris and can be cleaned out with each boiler service.

My system is clear, how do I increase the pressure on my boiler


Once your central heating system is clear, you’ll need to top up the boiler’s pressure. Do this, you’ll need to find the braided hose with a valve on it (external filling loop). Opening this valve will allow water into your heating system, and therefore pressure.

Be careful and open the valve slowly. Overfilling your boiler is going to put excess pressure on boiler components (as we mentioned with the boiler pump above), and that’s going to mean spending time draining water/pressure from the system.

When topping up my boiler’s pressure, what pressure should I be aiming for


Typically, most modern boilers will work best at around 1.3 bar (please check your owner’s manual for exact pressure). However, anything between 1-1.5 bar will be fine, if the pressure isn’t dropping any further.

When topping up your boiler, be sure to keep an eye on the pressure gauge. Due to it being directly linked to the pressure in the system, the gauge will move around a lot until you shut off the valve. It’s worth opening the valve for a small amount of time, then shutting off the valve to determine the exact pressure of the boiler.

My boiler pressure is too high, what can I do to get it back to 1.3 bar


If your boiler pressure is too high, you’ll need to remove some water from the heating system in order to keep your appliance from locking out. The easiest way to do this is to find the drain cock, connect it to a hose and open it, allowing water to escape outside.

However, if you can’t find the drain cock, an alternative is to drain water from a radiator.

If you can’t find the drain cock, you’ll need to drain water via the radiators.

How do I remove water from my radiators


You’ll need to locate the bleed value (usually at the top on one side of the radiator). It would be useful to buy a specifically designed radiator key; however, some newer valves have a space to use a screwdriver.

When you open the valve, you’ll notice a hissing noise; this is air being removed from the radiator. You’ll need to remove air from all radiators, before topping up the boiler. Air being lost will reduce the pressure, and therefore, you might not have to drain water from the system.

After bleeding all radiators of air, check the pressure gauge. You’ll notice it will have dropped. If it’s dropping to below 1.3 bar, you’ll need to top it up.

If it’s still too high, find one radiator, and bleed it again. But this time, instead of letting air escape, let water drain into a container (you’ll need to protect walls and floors). Have someone monitor the pressure gauge where possible.

If my system was leaking, what other problems could it have caused


The problem with leaks, is it’s not just the leaking part that needs to be fixed. If the leak was inside the boiler, anything from the gas valve to the PCB could have been damaged.

You’ll want to get your boiler engineer to check all the internal electrical components to check they haven’t been damaged. On some occasions, we’ve found that the internal damage caused by a leak across multiple components, means a replacement boiler is the most cost effective option.

But this will depend on the condition of your boiler, it’s age and if there’s any warranty left. New boilers will come with up to 10 years warranty, so things like a heat exchanger would have been fixed free of charge.

Other Biasi boiler issues


For more boiler issues regarding the Biasi Boiler then please visit the Biasi Boiler Problems And Cures page.