Contact Us 24/7 for Fast and Reliable Plumbing Services

Ask John Boiler Pressure Loss Main Image
Ask John Boiler Pressure Loss Main Image

Why Is My Boiler Losing Pressure?

John Turpin is our resident home service repair expert here at Service Direct. He’s got the knowledge and experience to help homeowners like you make sense of most home repair issues. And with Service Direct, we connect you with top-tier service professionals to help with any repairs needed.

Boiler Losing Pressure? Find Out Why Here!

The encouraging aspect is the fact that there is often just one problem that contributes to low boiler pressure. The disappointing part is that placing water in the equation without also correcting the problem won’t solve anything. You have come to the right spot, nonetheless, as you will be able to learn how to resolve low pressure in your boiler and restore the proper pressure reading.

The pressure within a contemporary boiler will continue to drop owing to leaks 99 times out of 100. These leaks may occur anywhere in the heating system, including the boiler itself.

Having to repair a boiler because the pressure inside has dropped is one of the most typical types of boiler problems. Here, you will learn of the most typical factors that contribute to a boiler’s consistent loss of pressure.

Ask John Boiler Leaking Pressure
A leaky boiler can cause your radiator to fill with air rendering it cold.

Why Does My Boiler Pressure Keep Dropping?

If the pressure in your boiler continues dropping, you are not the only one having this problem. If you find yourself having to depressurize your boiler on a frequent basis, there is likely something wrong with it. Fortunately, the repair process can be straightforward.

The pressure within the boiler being too low signals one of many typical causes of malfunctions that occur with boilers. Because of leakage and other boiler defects, a boiler’s pressure might gradually decrease over time, which can result in a lack of hot water and central heating. Because of this, it is essential for you to have the ability to recognize the signs that a boiler’s pressure has dropped and know how to restore it.

The Pressure Relief Valve of the Boiler Is Broken

The typical operating pressure range for a contemporary boiler is 1.0 to 1.5 bar. However, in the event that there is some kind of issue, such as a leak in the boiler, their pressure may surpass 3 bar.

The pressure release valve detects an abnormal change in the system pressure and then releases the pressure. When the pressure release valve on the boiler ever fails, then the boiler will begin to leak water and will experience pressure loss.

A Flaw in the Heating System’s Auto-Air Vents

It’s possible that your heating system can gather air pockets through time and you can be sure that this will happen when you replenish them. The ideal option is to bleed every radiator in your house or business, although the auto air vent (that is often located within the boiler enclosure on present-day boilers) may also assist to tackle this issue that ends up hurting boilers.

On the other hand, if the car’s air vent is broken, it may have a leak that causes the pressure to drop.

The Towel Rails, Radiators, or Radiator Valves Are Leaking

This is by far the most prevalent factor that contributes to a boiler’s loss of pressure. Even the tiniest cracks in your system’s plumbing might cause the pressure to drop.

Our recommendation is that you do a visual inspection on all towel rails, radiator valves, and radiators. If you find a sign that water is leaking out, then this is most likely the offending item. Even a little leak in a radiator valve may result in a significant loss of pressure in your boiler.

If the connections are particularly loose, carefully tightening these loose connections up should fix the boiler pressure problem. In the event that it does not, the component at fault will have to be fixed or replaced.

Ask John Boiler Pressure Drop
HVAC experts can test your HVAC system for leaks.

The Radiators Are Completely Filled with Air

After having repairs done to the heating system in your house, there is a chance that it has accumulated some air inside the radiators or towel rails in your home. Utilizing a bleed key is the method by which you may relieve the pressure in the system.

In order to bleed radiators or towel rails, you need to gently open the vent using the key. You’re going to hear hissing sounds coming from the trapped air. As soon as the air flow ceases, water will begin to drop and this is your cue to shut the vent off completely.

Repeat this process on each and every radiator or towel rail that is located throughout your home. It is advisable to bring along a small container in which to catch any water that may leak and a towel with which to preserve any carpets. Always note that bleeding the radiators results in a decrease in boiler pressure.

A Low-Quality Expansion Vessel

It’s going to be necessary to repressurize the expansion vessels every once in a while. Should they not be, they have the potential to alter the pressure within your home’s boiler. It’s possible that this is the root cause of the boiler’s loss of pressure in certain instances.

However, a leaky Schraeder valve is a far more plausible explanation for the problem. This corresponds to the valve of the vessel which will seem to be identical to the valve of the inner tube found in your vehicle. Loss of pressure in a boiler might be the result of a defective valve. There is also the potential that the vessel’s diaphragm has deteriorated over the course of time, leading to the loss of boiler pressure at that location.

In the event that repressurizing the expansion vessel does not work, or in the event that the possible culprit is the Schraeder valve, you will have to replace the vessel entirely in order to prevent the boiler from losing pressure.

Our in-house home repair guru, John Turpin, provides an insightful analysis of why your boiler might be experiencing pressure fluctuations. He offers a range of solutions and DIY tips to help you effectively address this issue. Stay tuned for his expert advice and practical guidance on maintaining optimal boiler pressure

The Boiler Is Leaking Through Its Soldered Joints

Obviously, leaks are the main reason why boilers lose air. If the machine is extremely old, there is a strong potential that soldered parts have gotten weak, which might produce a new leak. The pressure within a system may begin to drop with as little as the tiniest of leaks.

If you are able to locate the source of the leak, contact a Gas Safe engineer or submit a service request to the company that takes care of your boiler so that they may re-solder the joint and stop the leak. If you tap into the filling loop to add more water to the boiler, you will notice the pressure climb to where it should be. After that, watch the pressure gauge to make sure there isn’t any more loss of pressure.

Systematic Leak Detection

Detecting leaks in your home’s heating system is a crucial step in maintaining boiler pressure. To systematically search for leaks, start by inspecting visible components like radiators, valves, and pipes for any signs of water. Look for damp spots, rust, or mineral deposits, which can indicate slow leaks. Pay special attention to the areas around radiator valves and pipe joints, as these are common leak sites. 

If there’s no visible leak, consider checking hidden areas such as under floors or behind walls, as leaks here can go unnoticed. It’s also advisable to listen for hissing or dripping sounds, especially when the heating is on, as these can signal a leak. For more elusive leaks, you might need to employ professional methods such as pressure tests or thermal imaging. Regularly checking for leaks, even small ones, can prevent larger issues and maintain your boiler’s efficiency​​​​​​.

Maintenance and Regular Checks

Regular maintenance and checks of your boiler system are vital for its longevity and efficiency. An annual service by a qualified engineer is recommended to ensure all parts of your boiler and heating system are functioning correctly. During these checks, the engineer can identify potential issues such as worn out parts, corrosion, or sediment build-up, which could lead to pressure loss or other malfunctions. 

They can also check and repressurize the expansion vessel, inspect the pressure relief valve, and ensure the system is properly sealed and free from leaks. Regular maintenance can also improve energy efficiency, leading to lower heating bills and reducing the likelihood of unexpected breakdowns.

Between professional checks, keep an eye on the boiler pressure gauge and repressurize the system if needed. Also, bleed your radiators regularly to remove trapped air, as this can affect system pressure and efficiency. These proactive steps can significantly extend the life of your boiler and heating system​.

Ask John Boiler Maintenance
Regular maintenance catches issues early avoiding big repair bills.

Leaky HVAC Boiler FAQs

Is the pressure valve of my boiler faulty?

It’s quite improbable, but the pressure gauge of your boiler might be malfunctioning. This is a serious problem, particularly if the erroneous reading prompts frequent maintenance.

You would definitely detect a leak of that extent if the pressure gauge didn’t react when you topped up the boiler.

Why does my boiler pressure keep getting lower?

One of the following is probably the cause of your boiler’s chronic loss of pressure: Centralized heating system leakage, deflated expansion vessel, water leaking from pressure release valve, or cracked or slightly opened filling loop.

What should I do if it still leaks after being repaired?

If you have addressed the concerns that have been raised above but you are still experiencing low boiler pressure, and the equipment is not covered by a warranty, you will need to seriously consider a replacement of your boiler entirely.

Hire a Local HVAC Expert

The strategies outlined are practical DIY methods for identifying and addressing the causes of low boiler pressure. However, if you find these steps challenging or if the problem persists, it’s advisable to seek assistance from a qualified HVAC pro. For professional support, you can easily get in touch with a local expert by using the contact information provided on this page.

Get a Quote

Let’s connect you to a top-tier local service professional

Contact Us Today for a Quote

or Call (855) 653-0686

Thank You!

Your project has been sent to a top-tier local service provider who’ll be in touch soon to take the next steps.

or Call (855) 653-0686