Is it Safe to Keep Resetting my Boiler Pressure?
Pressure loss is a common fault with boilers. Many people know how to bring the pressure up again, but how often is it OK to do this? When is it time to call a boiler engineer or plumber for boiler pressure issues?
This article will explain the most common causes of this problem and things you can look out for yourself before calling out a heating specialist.
What is Boiler Pressure?
Boiler pressure is a critical element that affects the performance, efficiency, and safety of a boiler. Boiler pressure refers to the pressure of the steam generated inside the boiler by heating water, which is then circulated through pipes to the hot water and central heating system.
As more heat is added to the water, the pressure inside the boiler increases. The pressure is measured in pounds per square inch (psi) or bar. The higher the pressure, the higher the temperature of the steam.
Boiler pressure affects the efficiency of the boiler. The higher the pressure, the more energy is required to produce the steam. This can affect the overall efficiency of the boiler and increase fuel consumption.
To prevent the pressure from becoming dangerously high, boilers are equipped with safety devices that regulate the pressure and prevent it from exceeding a safe level.
Most boilers come equipped with a pressure gauge, which is generally located on the front of the unit. This gauge provides real-time information about the current pressure of the system. By monitoring the pressure gauge, it is possible to identify when the boiler pressure is low and take the necessary steps to address the issue. Maintaining the proper boiler pressure is important for ensuring that the system is functioning efficiently and effectively.
What Should my Boiler Pressure be?
Boiler pressure should be between 1 – 1.2 bar when cold. This will fluctuate when the heating is on and when the heating is off. This will range between 1 bar when cold and approximately 2 bar of pressure when the heating is on. Most boilers will have some kind of display showing the current pressure. In older boilers, this is likely to be a dial with a pointer. More modern boilers usually have digital displays. You may have to scroll through a menu on these, to find what you’re looking for.
If the boiler pressure gauge is reaching 3 bar or above when the central heating is on, this will indicate a fault inside the boiler. This could be a faulty expansion vessel or even a blockage. In rare cases, it could be that an additional expansion vessel is required across the system.
When the pressure gauge reaches 3-3.5 bar, the pressure relief valve will release the pressure of water and safely terminate through the pressure relief valve and pipe. This is one of the most common reasons why the boiler can lose pressure.
How Often Should a Boiler Lose Pressure?
It is quite normal for the pressure in a boiler to drop or vary occasionally. If your boiler’s pressure decreases between one to two times per year, there is usually nothing to be too worried about. However, if the pressure in your boiler drops frequently, it could indicate a problem, and you should contact a qualified gas engineer for assistance.
What causes Boiler Pressure Loss?
Boiler pressure loss is generally caused by a leak or a fault in the system. One of the most common places to find a leak is on a radiator valve so it’s a good idea to check them all for any signs of a leak. If there is a leak in this area, you may find rust on the pipe or stains on the carpet around the pipe.
Low Boiler Pressure Caused by a Leak Elsewhere in the Heating System
The most common cause of boiler pressure loss is a leak in the system. Imagine your entire heating system as a closed, water-filled loop. Much the same as a puncture in a car tyre, the very smallest hole anywhere in the system will leak, causing the pressure to drop.
Identifying the leak is the tricky part. The water-filled loop that is a heating system has many areas that could leak –
• The boiler itself
• Pipes
• Joints
• Valves
• Radiators
We regularly find leaks in all of the above, but in our experience, most leaks come from joints. Weaker than the rest of the pipework they are more prone to bursting. Occasionally it’s just the case that the joint wasn’t tightened enough.
Annoyingly, leaks can be in places that aren’t so easy to identify. Much of your pipework is hidden, so look out for damp patches on walls, floors or ceilings. Other signs such as mould or peeling paintwork can also indicate a leak.
Can a boiler lose pressure without a leak?
Yes, a gas boiler can lose pressure without a leak. Loss of pressure can be caused by a variety of factors, including normal usage, bleeding radiators, or a faulty pressure relief valve. If you notice that your boiler’s pressure is dropping regularly, it’s a good idea to consult a qualified heating engineer to diagnose and fix the issue.
Low Pressure Caused by Boiler Fault
Boiler component faults can be another reason for pressure loss. The usual suspects are –
• Expansion vessel failure
• Relief valve problem
• Pump malfunction
Expansion vessel failure is a fairly routine problem. The role of the expansion vessel is to accommodate the difference in pressure between hot and cold water in your system. The flexible diaphragm inside the sealed tank does have a limited lifespan and will need replacing if it fails.
Less common issues with pumps, relief valves or any other component of the boiler can also be the cause of pressure loss and should always be investigated by a qualified boiler engineer.
Do All Makes of Boilers Lose Pressure Over Time?
Yes, it is normal for there to be occasional pressure loss, whatever the make of boiler, including all the top manufacturers:
• Baxi
• Vaillant
• Ideal
Do I Need Expert Help When My Boiler Keeps Losing Pressure?
If you have recently repressurised your boiler system but notice that the pressure has dropped again or if you are consistently having to increase the pressure, it is recommended to contact a Gas-Safe registered engineer for a thorough inspection. This could indicate a potential leak elsewhere in the system that may have gone unnoticed or could be a sign of an issue with your boiler.
By consulting with a qualified engineer, you can receive expert advice on how to address the problem and potentially avoid further complications. The engineer will be able to identify the root cause of the issue and provide appropriate solutions to fix the problem. It is important to address these issues promptly in order to maintain the safety and efficiency of your boiler system.
Found a leak?
Then it’s time to call a plumber or central heating specialist. Fixing these leaks shouldn’t take too long and should solve the pressure loss problem.
Do I Need a New Boiler?
In the absence of any obvious leaks, it is well worth getting a boiler engineer to check your system for faults. The engineer will run some tests and find out what’s going on. Many faults can be inexpensively repaired, but sometimes it’s the case that it’s time for a new boiler.
Unfortunately, no boiler lasts forever. If your boiler is frequently showing low-pressure readings, is more than 10 years old, and is no longer functioning at its best, it is probably time to invest in a new boiler.
So, if you’re finding you have to constantly adjust the pressure on your boiler, it’s time to take action. Why not give us a call on 020 313 77749 for some friendly, expert advice?
WaterGuys will pinpoint the problem and advise on the best solution.
Article revised March 2023