Glow-Worm Boiler F.24 Fault Code
The Glow-Worm fault code F.24 relates to the temperature rising too quickly and here we have Q & A or require an engineer for an emergency boiler repair.
The Glow-Worm Boiler Fault Code F.24 Error Common Q & A
Just below, we have a list of common questions relating to the F.24 fault code on the Glow-Worm Boiler.
- What does the F.24 fault code mean on my Glow-Worm boiler?
- Why does my boiler lock out and display the F.24 fault code?
- What problems lead to the F.24 fault code being displayed?
- What causes a blockage in the central heating pump?
- Can a blocked heating pump be fixed?
- My engineer thinks I need a new pump, how much will this cost?
- How can changing the pump’s speed setting clear the F.24 fault code?
- How can low boiler pressure contribute to the F.24 fault code being displayed on my Glow-Worm boiler?
- What causes low boiler pressure, and how can I fix it?
- What do air locks do in a heating system?
- Should my boiler lose pressure after bleeding radiators and towel rails?
What does the F.24 fault code mean on my Glow-Worm boiler
If you’re seeing the F.24 fault code on the display panel of your Glow-Worm Energy boiler, it means the rise in temperature logged, is too fast.
When a boiler fires up, it should slowly increase in temperature. If there’s a quick rise in temperature, that signals that there’s a problem.
Why does my boiler lock out and display the F.24 fault code
A quick rise in temperature could mean that internal boiler components are being damaged. So, in this instance, the boiler locks out to protect these components. That’s a good thing, as it’s going to mean avoiding expensive repair bills.
What it also means, is that you shouldn’t keep trying to reset your boiler to clear the F.24 fault code. Even if you do manage to trick the boiler into working temporarily, you’ll be causing long-term damage.
Call an emergency boiler repair company. Once they’re able to highlight what the problem is and fix it, they’ll reset your boiler to clear the fault code.
What problems lead to the F.24 fault code being displayed
A quick rise in boiler temperature, doesn’t point the finger at one specific problem. It could be one of a few different problems, or a combination, including:
- A blocked pump
- Wrong speed setting on pump
- Low boiler pressure
- Air locks
What causes a blockage in the central heating pump
The most probable cause of a blockage on a central heating pump, is sludge. Sludge in heating systems is a real killer. It can stop radiators working, as well as the pump from operating.
Sludge is a combination of rust and limescale. This combines to create dirty water in the heating system. Whilst the majority of this is broken down into miniscule particles, some large particles remain. As they travel around the heating system, they can get lodged in parts, including the heating pump.
When there’s a blockage, the pump’s ability to circulate water is going to be restricted. It’s not going to push heated water from the heat exchanger as quickly as it should. Essentially, it’s overheating.
The temperature rises quicker than it should, and the NTC thermistor on the flow pipe recognises this. It feeds back this information to the printed circuit board (PCB), which then locks out the boiler and displays the F.24 fault code that you’re currently seeing.
Can a blocked heating pump be fixed
On many occasions, a blocked heating pump can be fixed. The unit can be removed, ready to be cleaned manually. After refitting the pump, your boiler repair company will then flush out the system, and replenish dirty water, with clean water.
The problem is, heating sludge will return over time. Rust will continue to break off pipework, radiators and towel rails. But, there are preventative measures that can be put into place.
After flushing out the system, your heating engineer will need to add inhibitor to the system. This makes sure all sludge particles are broken down. By then adding a magnetic system filter on the return side of the boiler, these particles can be caught and removed from the heating water, before they reach the boiler; this will prevent blockages occurring again.
For those in hard water areas, another preventive measure can be employed. Hard water leads to limescale build-up, and this can block not only the heating pump, but the heat exchanger. Limescale reducing filters can be fitted to combat this problem.
My engineer thinks I need a new pump, how much will this cost
Not all pumps can be salvaged. There’s little point paying labour costs to recondition a pump, if it’s on its last legs anyway. If you need a replacement, you’ll want a quality one; Grundfos are a well-known brand producing quality central heating pumps.
For a quality pump like Grundfos, expect to pay around £250 including parts and labour.
How can changing the pump’s speed setting clear the F.24 fault code
If the pump isn’t at fault, but the speed setting is incorrect, water flow will be too slow. Water will be staying in the heat exchanger for too long, leading a rapid rise in temperature.
A boiler repair company will be able to test the speed settings on the pump, making sure that the speed setting on your boiler is the correct one for your property.
Most pumps have three different speed settings. The bigger the length of the heating run, and the more radiators you have, the higher the speed setting will need to be, to give the correct flow of heating water.
How can low boiler pressure contribute to the F.24 fault code being displayed on my Glow-Worm boiler
If the pressure on your boiler is too low, the pump won’t be circulating water quick enough. With the pressure higher, it won’t have to struggle to pump, and therefore, it’s going to last a lot longer.
Your boiler should be set at around 1.3 bar of pressure. The gauge to check pressure is usually located on the control panel on the front of the boiler’s casing, or just beneath it.
If the pressure is below 1.3 bar, you’re putting your boiler under unnecessary strain. Once it drops below 0.5 bar, it will lock out completely.
What causes low boiler pressure, and how can I fix it
In most cases, the cause of low boiler pressure is a leak, somewhere in the heating system.
This could be a tiny leak in a towel rail, the boiler pump or a weeping radiator valve. The leak needs to be found and fixed, to stop boiler pressure dropping. Whilst you could just top up the pressure, if a leak isn’t found, the pressure will continue to drop daily. More importantly, if there’s a leak, this could be damaging your property.
Once the leak has been found and fixed, you can then top up the boiler’s pressure. There should be a braided hose with a valve on it, just beneath the boiler casing. This is the filling loop. When you open this valve, water enters the heating system, and the pressure gauge will rise. Keep the filling loop open until the gauge reaches 1.3 bar.
What do air locks do in a heating system
Air locks cause problems, and they shouldn’t be there. You should view air locks, the same as you would a blockage. When air locks are present, they create a virtual blockage, not allowing heating water to flow naturally.
They can occur in radiators, towel rails, and even the heating pump.
On a DIY basis, you can attempt to bleed the radiators of air, using a radiator bleed key. Open the valve, and you’ll hear a hissing noise. Once the hissing stops, that’s a signal that all air from that radiator or towel rail has been removed; move onto the next one.
The pump can also be bled of air. But, as this is a gas appliance, only Gas Safe boiler repair companies are legally allowed to work on one. Call one, and they’ll be able to bleed the pump in a matter of minutes.
Should my boiler lose pressure after bleeding radiators and towel rails
Compressed air takes up physical space in your heating system. So, when you bleed air from the system, there’s a chance that you’ll lose boiler pressure. If this is the case, you’ll need to use the external filling loop to top up your boiler.
Again, you should be aiming for 1.3 bar of pressure.
Other Glow Worm boiler issues
For more boiler issues regarding the Glow Worm then please visit the Glow Worm Boiler Problems And Cures page.