The F22 Code is probably one of the most common faults you will see, although depending on the model of Glow Worm boiler, you have this specific fault might have a different code.

There are few things quite so disconcerting as coming home or waking up to a malfunctioning boiler. A cold house, no hot water and an unhappy spouse and children are not something any of us would wish to experience. The good news with most modern boilers is that they will try to give you a clue as to what the problem or issue is in the form of a code displayed on the boiler. The bad news is at the time when the pressure is on, who knows where the boiler instruction manual is stored? 


This article aims to guide you through the process of identifying what the problem is and giving you some advice as to how to resolve that issue.

The F22 Code relates to a loss of pressure in your boiler, which is something that needs to be dealt with as a matter of priority. Some of the other codes you might see on Glow Worm boiler displays that also relate to a drop in pressure include

  • Code F9
  • Code F24
  • Code F32
  • Code F73
  • Code F74

Glow Worm Boilers

Glow-worm is one of the oldest boiler manufacturers in the United Kingdom. They have been making boilers since 1935 at the Derwent Foundry in Derbyshire. Their commitment and focus has always been on delivering highly efficient, reliable and cost-effective products. Glow-Worm was purchased by Valliant in 2001 but continues to operate under the Glow-Worm brand name

Why Is Low Pressure In A Central Heating System Such A Problem?

Every pressurised central heating system works by circulating water around your home. In much the same way as the human body works, the boiler is the key to the system, heating the water, and sending it on its journey around the radiators before the water returns to the boiler to be heated up once again. The process is then repeated ad-infinitum. Without sufficient pressure in the system, everything rapidly comes to a grinding halt, which is why the boiler will immediately stop working when it detects a drop in pressure. 

What Causes A Drop in Pressure In Your Central Heating System?

There are two main reasons why a central heating system would lose some pressure – one is not an issue, the other has the potential to be very serious. If you have owned your own property for any length of time, you will know that over time excess air can get into the system. This air will always rise to the top of the radiators, preventing the water from being able to fill your radiators properly. This will detract from your system’s efficiency and reliability, so the solution is to bleed the radiators. When you bleed the radiators, which is a simple DIY job, you are essentially doing the same thing as opening a bottle of carbonated water. Any excess air is released as soon as you open the bottle, as is any subsequent pressure buildup. As soon as you bleed the radiators in your home, it releases the excess air and a little water, causing the overall pressure in the system to drop. This is absolutely nothing to worry about, and you can easily increase the pressure again by releasing some more water into the system. 


If, however, you have noticed a drop in the system pressure and added more water, only to find the pressure dropping again in a relatively short period of time, then the reality is that you may well have a leak in your central heating system. 

Most people think not unreasonably that any leak will be apparent, with puddles of water or damp patches appearing, but unfortunately, this is not always the case. In many situations, your pipework may be hidden behind walls or under floorboards, which is a serious issue. If you have a leak but cannot find its source, it could and probably will be causing irreversible damage to your home. The key is to find the source of the leak and repair it as soon as you possibly can. 

This is a specialised job that requires knowledge, expertise, experience, and specialist equipment that a traditional plumber will not have. ADI Leak Detection are the original specialist leak detection company in the United Kingdom. We have a reputation for finding leaks where other companies have failed. Our team of specialists has many years of experience in the industry and can think outside the box, which is why they are so successful. If you are struggling to find the reason behind a sudden and sustained drop in boiler pressure, call ADI Leak Detection today. We will ensure that the pressure in your central heating system is restored and the pressure you are feeling is relieved, typically within one visit. ADI Leak Detection is the specialist company that delivers results time after time.