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Boiler Pressure Keeps Dropping? – Helpful Guide

In our guide to plumbing leaks, we mentioned that if your boiler pressure keeps dropping, it could be a sign of a water leak in your central heating system. As experts in water leak detection we frequently deal with people who have boiler pressure dropping from a water leak, stopping their boiler working.

Sometimes they are having to top-up their boiler regularly to make it work, whereas other times, especially with bad water leaks, the central heating system stops working altogether. Modern pressurised boilers generally require a specific pressure to operate effectively and might have a safety cut-out if the pressure drops too low.

It’s important to say that a one off small drop might be normal, especially if you have not used your boiler for some time (e.g. over summer) or if you have bled your radiators to release trapped air. Check with your manufacturer, installer or boiler engineer if needed on how to re-pressurise the system – it is generally straightforward but, if in doubt get help. However, fast losses in pressure or a boiler losing pressure repeatedly needs looking at and are more likely to be a boiler fault or water leak.

Boiler Pressure Keeps Dropping - Possible Leak, Yorkshire
Boiler Pressure Keeps Dropping – Possible Leak

Quite often, especially on modern boilers, if your boiler pressure keeps dropping that is accompanied by a warning message on the boiler such as an F1 Boiler Error (on some Ideal Heating boilers for example). In fact, taking Ideal boilers as an example, on their website page on boiler fault codes they say that ‘Flashing F AND 1 Low Pressure’ is “Water pressure is too low in the system and will require topping up to between 1 and 1.5 BAR”.

Boiler Pressure Drops
Boiler Pressure Drops from Water Leak

Other manufacturers and different models have different codes, check your manual or their individual website for details. So the question is…

My Boiler Pressure Keeps Dropping – Why?

If you do have a water leak in your central heating system that means your boiler pressure keeps dropping, where is the leak? It could be…

  • A water leak from the boiler itself, such as the PRV
  • A water leak from a radiator on your central heating system
  • A water leak in your central heating pipework
  • A water leak in the connections between the above
  • A combination of the above, where you have more than one leak

The PRV issue mentioned first above, might be seen via the boiler tundish if you have one.

If you have ruled out a problem with the boiler itself (either yourself or via an engineer), then the challenge is to see if and where you have a water leak on your central heating system. As you will no doubt know, the pipework in your central heating system will often be hidden in walls floors and ceilings, making finding leaks harder. They could even be underground under floorboards or a water leak in concrete floors.

Also possibly in underfloor heating leaks if you have that installed. As you might expect, they are generally much harder to find but we are experienced at locating them and have the right tools too.

This is where a leak detection expert such as ourselves comes in, we provide a local, professional leak detection service and trace and access services across the region of York, surrounding areas and the Yorkshire Coast.

If you think you have a leak, act early to find it before the water damage caused gets worse. Over time, water from a leak can cause damage to your property and it is best to catch these things early. Apart from property damage, plumbing leaks can cause other problems such as damp and mould problems. It can also be very inconvenient if you cannot use your heating because of it!

Boiler Pressure Keeps Dropping?

You can see why your boiler pressure keeps dropping, even from a small leak by looking at our article on how much water a leak loses, even from a small drip. The amount soon adds up!

We discuss the subject of when your boiler keeps losing pressure in our article about Christmas water leaks, possibly one of the worst times for your boiler to stop working!

How do you find a Central Heating Leak?

We use state of the art leak detection equipment and processes to help find leaks including:

  • Thermal Imaging Leak Detection (important for heating systems)
  • Moisture Meter & Moisture Mapping Leak Detectors
  • Tracer Gas Leak Detection
  • Acoustic Listening Leak Detection
  • Water Pipe Tracing Leak Detection (to trace heating pipes)
  • Water Flow and Pressure Testing Leak Detection
  • Water Meter Leak Detection
  • Salts Analysis Tests to determine the water source
  • Other miscellaneous leak detection tools and devices
  • All combined into our bespoke tracking and reporting tool

Different types of plumbing leaks leave different signs that our team are experienced at watching out for and monitoring. We use these tell-tale signs to help narrow down and locate a central heating / boiler in your property. This includes water leaks that are not visible to the human eye, even very small leaks.

So if you think you might have a central heating leak, contact us.

What Should Boiler Pressure Be?

When looking at why your boiler pressure keeps dropping, the obvious question is what should it be at? Clearly this will depend on the specific make and model of boiler you have. Check your manual or manufacturers website for more details. However, typically, modern pressurised boilers tend to operate in the 1.0 to 2.0 bar range. This can also vary when the system is operating vs ‘idle’.

Just like boilers have warnings and safety cut-outs when your boiler pressure keeps dropping, they often have safety features around boiler pressure being too high too, although this is a less common issues. Interestingly, if pressure is too high, it can but strain on the central heating system and possibly cause a leak at a weak point for example. Ironically, this can be an initial cause of why your boiler pressure keeps dropping.

Top Tip
If you are having to regularly top up your central heating because your boiler pressure keeps dropping, get it checked asap.”

Leak Detection Team

How Can I check My Boiler Pressure?

Most boilers have either a manual pressure gauge (like the one below) or a digital one. They often have coloured ranges displayed on them, such as green for normal and red for high or low boiler pressure for that specific boiler.

In some instances when your boiler pressure keeps dropping or happens fast, you may be able to actually see the needle on the pressure gauge dropping. The faster this happens, the more likely the leak (if you have one) is to be bigger. In some instances, if the leak is a bad one (such as a completely broken pipe) you may not be able to re-pressurise the system at all.

Boiler Pressure Keeps Dropping - Water Leak Detection, York - Yorkshire.
Boiler Pressure Keeps Dropping – Water Leak Detection

Other Signs of a Possible Central Heating Leak

Other than situations where your boiler pressure keeps dropping, there are other things to watch out for (at the same time) that could be signs of a central heating system water leak:

  • Visible Damp / Waterdamp patches on walls, floors or ceilings (especially near pipes)
  • A Higher Water Bill – indicating that you are unexpectedly using more water
  • Sounds of a Plumbing Leak – unusual noises from drips, trickles or flows of water
  • Structural Damage – cracks in walls or ceilings or ‘soft’ spots in floors etc.
  • Strong Smells – of dampness or unusual ‘musty’ smells in your home
  • New or Increased Mould – plumbing leaks can help cause this
  • Low Water Pressure – lower than normal (or total loss of) water pressure

The second thing on that list about Water Bills is relevant to our article on water meter reading, which can help with spotting leaks and seeing how much water you use. Speaking of useful information, we have a really helpful guide to a fire triangle.

Clearly, if you have a situation where your boiler pressure keeps dropping and you have one or more things on this list, the higher the chances of having a central heating / boiler leak. So if you do, or you just want help or guidance, get in touch with us today and we will be glad to help you.

At Rainbow Restoration – York & Yorkshire Coast we are experts in Leak Detection and Water Damage Restoration, so if you need help finding a water leak or getting your property back to normal after a leak or flood, get in touch with our friendly local team who will be happy to help you with this.

Leak Detection Logo
Leak Detection Logo

Is 2.5 or 3.0 bar too high for a boiler?

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Clearly whether the bar pressure is too high will depend on the type and model of boiler you have in your property. Each will have it’s own optimal range for operating most effectively and, most likely, cut offs for being to high or low pressure. That said, for most domestic central heating boilers, over 2.5 bar would be on the high side. If needed, check with your manufacturer or the instructions for your boiler.

What happens if a boiler pressure is too high?

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If a central heating boiler pressure gets too high then, normally (depending on the age, make and model of your boiler), it will trigger the Pressure Relief Valve which will release water from the system and lower pressure back to acceptable levels. This is a safety feature to protect the boiler, the central heating system pipework (and connections) as well as your property as too high pressure could cause a water leak and water damage. This ironically will drop your pressure too low.

Can boiler pressure keeps dropping be a water leak?

Absolutely, when your boiler pressure keeps dropping, one of the most common causes of this can be a water leak on your central heating system pipes. Because these pipes are often hidden in walls, floors or ceilings leaks can be difficult to locate but a professional leak detection company such as us can help locate your water leak for you.

Can a leaking radiator cause boiler pressure to drop?

Leak Detection Logo - Small

Yes, a leaking radiator can cause boiler pressure to drop in your central heating, as with a leak on any of the connected water pipes. If your boiler pressure keeps dropping, that could be the cause. Many boiler systems are pressurised, ‘closed’ networks within your home or business. The boilers operate at an optimal level in a pressurised system and may stop operating if boiler pressure falls.