What are boiler filling loops & how to use them?
The Boiler Filling Loop is a temporary connection to mains that allows you to repressurise your heating system and add water.
In this article, we will explain what an external boiler filling loop is used for and why it’s so important. This small, but very useful component will save you a lot of time and headaches and potentially loss of money if you know how to use it rather than calling a Gas Safe registered heating engineer!
What is the purpose of repressurising my boiler & central heating system?
You may need to repressurise the boiler with an external filling loop for a variety of reasons, including:
- The boiler pressure has fallen below 1 bar
- Your radiators have been bled
- There’s a tiny leak
- The boiler is having a problem
It is important to learn as much information as possible about the Boiler Filling loop. If you check the pressure gauge, your boiler’s pressure will be at an acceptable level (around 1.5 bar). However, if this is different or not displaying the proper information, it could cause permanent damage.
It’s even more frustrating when low boiler pressure can be solved by a quick glance at the pressure gauge and repressurising system.
You can use external filling loops to connect to your mains water supply. This is necessary if your boiler or central heating water supply needs to be topped up.
How do you use a boiler filling loop?
Even if you aren’t sure how central heating and boilers work, using a boiler filling loop is an easy task. Some boilers have internal filling loops now but these tend to be on the more modern and better boilers.
If your boiler pressure drops too low, you will need one. Your boiler’s performance will be affected if it drops below half a bar. Your filling loop might be attached with blanking caps if it has just been installed.
To repressurise your boiler you won’t need any other tools. You can simply turn the filling valves with your hands. Before you begin, however, make sure the valves are in the “off” position.
- Use your hands to ensure that the filling loop stays in place.
- One valve should be turned so it aligns with the pipe’s direction
- Slowly turn the other filling valve. The water will begin to flow through the mains into your system.
- The system should allow water to flow through it. Your boiler’s pressure should begin to rise as a result.
- When it reaches 1.4 bar, shut down both valves.
Some people prefer to have the filling loop attached to the boiler. This is against the boiler filling loop regulations. They state that your filling loop must be disconnected from your boiler if it’s not being used. It can cause irreparable damage and even death to your boiler’s filling loop. It can also be dangerous for children living in the home.
Children can knock out the filling loop valves. This could cause water to back up into the system. It would also raise the boiler pressure, which could lead to more problems.
Read our quick guide on how to repressurise a Worcester boiler here
Why are there filling loops that are not connected to the boiler at all times?
This is a simple one. Because water regulations prohibit water from returning to the mains, the connection between the boiler and filling loop is temporary. You can’t use the same water from your radiators as the water coming out of the taps and showers. This is a very dangerous thought.
If you find yourself using the boiler filling loop for repressurising frequently, it could be an indication that there is a problem in your boiler or heating system.
The engineer should make sure that the boiler filling loop is accessible to you when the boiler is being installed. Boiler filling loops can be replaced if this is not the case.
A quick Google search will reveal that most online shops and services charge between £7 to £20 for a filling loop. This component is essential for repressurizing your boiler. It’s worth having on hand!
The boiler’s filling line will contain at least one stop valve to regulate the flow of water. A double check valve helps prevent water from returning to the mains.
What is the purpose of my filling loop and why do I need it?
The filling loop is designed to help you repressurise your boiler when the pressure drops too low and this is not something you should do all the time.
If you feel that your boiler is being topped up too often, usually more than twice per year, then there might be leaks. You could have problems with pipes, radiators or other heating systems like expansion vessels and pressure release valves.
No matter what the reason, your boiler should not be low in pressure all the time. It is important to locate the leak quickly so that your boiler doesn’t suffer further damage.
You will see further corrosion if you need to refill your boiler frequently. The corrosion eventually leads to a buildup of sludge in your pipes and radiators. This will cause your boiler to fail to heat up properly and will also lead to corrosion and component degradation that will create more problems.
If you find yourself using the boiler filling loop to pressurise frequently, it might be worth talking to heating specialists to get some reliable, friendly advice.
