If you want to make sure that your boiler keeps working well, you will have to ensure that your Glow-worm boiler pressure doesn’t drop too low. If your boiler pressure drops below a certain point, you will not have hot water or heating. 

The right boiler pressure is between 1 to 1.5 bar on the gauge when the radiators are cold. 

If you are having boiler issues due to glow worm boiler pressure, you are at the right place. Here, you are going to find out the best information about boiler pressure problems. You are going to get the best information about maintaining the right boiler pressure. 

What is the right boiler pressure?

If you notice that your boiler pressure has fallen under 1 bar, consider increasing your boiler pressure. 

In a cold system, if your boiler pressure is over 1.5 bar, you should decrease the boiler pressure. 

Right Glow-worm boiler pressure while heating 

You must be wondering, what should the glow-worm boiler pressure be when the system is turned on and hot.

The pressure can cross 2 bar when the system is turned on and working. You don’t have to worry about this level of pressure because this is pretty normal. Water, when heated, expands inside the boiler and therefore such pressure is normal. 

How to check the pressure on the Glow-worm boiler?

The right way to check the boiler pressure on a glow worm is to check the Glow-worm pressure sensor. The pressure sensor tells the right pressure. This is the only way you should measure the pressure because the sensors are designed for this specific task. 

Increase Pressure on Glow Work Boiler 

Here are the steps to increase the pressure on a glow-worm boiler. 

You have to open two valves at both ends of the boiler to ensure that some water gets into the boiler. 

Remember that you don’t open both filling loop valves right away since the water pressure may be too high for the boiler. 

Glow -Worm Boiler Pressure Too High 

If you want to fix high glow worm boiler pressure, go through this section. 

Naturally, you may be wondering why your Glow-Worm boiler pressure is so high.

The pressure may rise due to several reasons. Most of them are listed below. 

Reduce glow worm pressure through these methods 

Most of the time, the glow worm boiler pressure can be reduced by letting some air or water out of the system. 

Here are some ways to reduce Glow-worm boiler pressure in case it is too high 

Once the air has bled out of the radiators, you can bleed some water out of one radiator. You have to bleed the water until the pressure comes between 1 to 1.5 bar. 

You can collect the water in a bucket and put some towels on the floor to make sure the water does not spread around. 

Drain water from the drain off valve 

You will find a drain-off valve in almost all central heating systems. Drain-off valves are used to drain water out of your heating system. Drain-off valves can be found on radiator valves, pipes and at the bottom of the boilers. 

You can always use a hose to drain the water through the drain-off valve. The hose can be used to take the water from the drain-off valve to a drain or a sink. Once the hose is connected, you can open the square nut slowly until the water drains. 

You have to check the pressure gauge till it has reached a reading between 1 – 1.5 bar. 

Relieve Pressure through the pressure relief valve

You will find this pressure-relieving system on every central heating system that is pressurised. There is mostly a turning mechanism or a level that allows you to reduce the pressure immediately. 

Most find it to be the simplest and most convenient way to reduce the pressure without needing to bleed radiators. However, you should be careful about one thing. There is only one issue with this method. Sometimes, the pressure relief valve may not close properly. It may happen only if your system is dirty. It is not common but you should know that it can happen. If you feel that the valve isn’t shutting down completely, you may need to get it replaced. 

Reduce pressure by cracking a nut 

This is an easy, but messy way to reduce pressure in the Glow-worm boiler. You can crack a nut to relieve pressure. You won’t need to bleed the radiators if your boiler pressure gets very high. Even if this is messy, it is a good way to get the task done. You need to put a few towels on the floor and a bucket under the nut so that the water doesn’t spill around. 

You just need to crack the nut slowly until you see the water coming out. You need to monitor the pressure gauge to see that the desired pressure is achieved. 

Reduce boiler pressure through the magnetic filter

You should know that you can also reduce your boiler pressure through the central heating magnetic filter. Make sure you keep a towel and bucket under the filter. If there’s a nut on the bottom of the system, open it slowly. Otherwise, you can slowly open the bleed valve with a key. 

.You will see water coming into the bucket. Keep an eye on the pressure gauge and aim for a pressure of 1 to 1.5 bar on a cold system. 

What if the Glow-worm boiler pressure gets too low?

Most boiler systems stop working when the pressure gets too low. Low boiler pressure is one of the most common issues that you can face. However, the solution is also pretty simple. In case your glow-worm pressure is too low, you can repressurise it to fix it. 

Why is my Glow-worm boiler losing pressure?

There may be many reasons why your Glow-worm boiler is losing pressure. Some of the main reasons are:


Your Glow-worm boiler pressure should stay between an optimum range to function perfectly. If your glow-worm boiler pressure is too high or too low, then you need to fix it. 

If the pressure is too high, you just have to reduce it. 

If the pressure is too low, you have to repressurize it. 

If you understand how it works, you won’t have to call a plumber and pay them every time you face this issue. 

However, in case you are losing pressure too frequently, you should get professional help and get this problem fixed. 

We hope that you found this information helpful. Feel free to reach out to us if you have any questions related to Glow-worm boiler pressure. We will be glad to help you out. 

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