Is low boiler pressure dangerous?

The majority of modern boilers often don’t need much more attention than their annual service and the occasional look at the boiler pressure gauge to inform you of the water pressure circulating in the heating system. Keeping your boiler at the right pressure is extremely important as if the pressure is too low, the system won’t work as efficiently. In this article, we’ll be answering whether having low boiler pressure is dangerous and how it can be fixed.

What should your boiler pressure be?

Normal boiler pressure should sit somewhere between 1 and 2 bars. The right boiler pressure is typically marked as a range in green on the pressure gauge, with red being the low and high boiler pressure zones. Your boiler might keep working if the pressure is in the red zone but if it’s shutting itself down or won’t turn on, then you’ve got a problem.

Even when your boiler is working as it should be, it’s advised to occasionally check the pressure. As well as this you should know how to use your boiler pressure relief valve to release boiler pressure when it’s too high and how to increase the pressure when it’s too low.

Is low pressure in your boiler dangerous?

You will be able to tell when your boiler pressure is too low if:

There isn’t any heating or hot water
Your radiators aren’t heating up properly
The dial on your pressure gauge has dropped

The good news is that low boiler pressure isn’t a danger. Sometimes, central heating systems can develop small leaks, similar to a tyre having a slow puncture. You might not notice any water escaping, but over time the pressure in the system keeps falling until it is too low.

If you have recently bled your radiators, you might notice the boiler pressure falling. Bleeding the radiators gets rid of any air within the system, which can lead to changes in the boiler pressure. Despite there not being a danger, you could be wasting a lot of money on your energy bills if your boiler pressure is too low, so it is important to address it.

How to increase your boiler pressure when it’s too low

Fortunately, you can usually increase your boiler pressure yourself without having to spend money on an engineer. If you have already done some research into this, you might have seen it referred to as ‘re-pressurising’ your boiler. Following the below steps can help you top up your boiler pressure:

First turn off the boiler
Look for an external filling loop underneath the boiler – it is normally a short length of braided hose connecting two water piper with levers at both ends to operate valves.
If you can’t locate a filling loop, your boiler might have a keyed filling loop or a keyless internal filling loop instead, you should check your boiler’s instruction manual if you can’t find it.
Turn both valves so that the levers are in line with the direction of the braided hose. You should hear water running and see the boiler pressure gauge increasing.
At around 1.2 bar, turn off both valves.
As long as the pressure stays up and there aren’t any obvious indications of leaking water, it is safe to turn the boiler back on.
After the boiler has been on and had the time to cool down again, check that there hasn’t been any significant pressure drops.

Normally, you should not need to increase your boiler pressure very often. However, if it is dropping more than once or twice a year, you should look at all visible pipes for any signs of water leaks. You might also see green deposits close to joins in copper pipework or stains on the skirting boards or ceilings. If you see a leak or your boiler pressure continues to drop, it probably requires further investigation by an engineer.

Summary

Even though low boiler pressure isn’t dangerous, it’s still important to get the pressure back to normal as soon as possible. If you need affordable boiler parts to fix a problem with your boiler NBS can help. We offer a wide range of boiler spare parts that will not only help you get your boiler back up and running effectively quickly, but also save you a lot of money on buying parts too. Contact us today if you have any questions or need help finding the right part for your boiler.