Radiators not working? Here’s how to check your boiler pressure

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If your radiators aren’t heating up when they’re supposed to, there are quite a few reasons why it could be. But, if you’ve got a combi boiler, then the most common culprit is often a low water pressure.

Your boiler should usually be operating with a water pressure between 1 and 1.5 bars, but can work just fine if the pressure is a bit lower than that. However, if it drops below 0.5, it will stop working, and your radiators won’t heat up.

 How to check your boiler pressure

It’s usually quite straightforward to check your boiler’s water pressure – there should be a dial on the front that shows it.

On newer boilers, this might be the digital display that also shows the water temperature. If the number 0.5 or below is flashing on the screen, then it’s indicating that your pressure has fallen below the point where your boiler will operate.

Older boilers will have a manual dial that typically goes from zero to three. If the needle’s closer to 0 than 1, then the pressure’s your problem.


Can’t find your pressure gauge?

The pressure indicator can be frustratingly well-hidden on some models. If it’s not in an obvious point on or near the main control panel, check your boiler’s manual for more information.

Lost your manual? Well, you might be able to find it online – Manuals Online is a useful resource for getting a free digital copy of all of those long-lost instruction booklets.

If you’re still struggling, give us a call – we’ll be able to help.


How to fix your boiler pressure

If you’ve got your manual to hand, it should have a guide to re-pressurising your boiler. If not, most models will require you to follow the same steps.

  1. Turn your boiler off, and let the system cool down.
  2. Find your filling loop – it’s a short grey hose that will usually be curved round in a U shape with a valve at either end, and it’ll be found either directly under your boiler, or close by.
  3. Keep an eye on your pressure gauge, and open both of the valves. You should be able to do this by hand, but on older models you might need to use a screwdriver.
  4. You’ll hear a hiss as water fills the system. Once the pressure gauge reaches between 1 and 1.5, close both of the valves one by one.
  5. Switch your boiler back on, and see if your radiators heat up.

It really is that simple! If you can’t find your filling loop then, once again, give us a call and we’ll be able to help out.


What to do if your boiler keeps losing pressure

A common cause is bleeding your radiators – which releases pressure from the system, and can cause your boiler to drop below its limit. If you’ve done this recently, then your loss of pressure is likely just a one-off issue.

If your boiler is losing pressure regularly, on the other hand, then you might have a leak – whether in your pipes, radiators, or the boilers themselves.

You may be able to find and fix the leak yourself if it’s a simple case of tightening up a pipe or radiator. If you can’t find a leak, it doesn’t necessarily mean you don’t have one – it could be in a place where you’re unable to reach it.

However, a leak isn’t the only cause of low pressure – a faulty pressure valve could also be the culprit, or it could just be that your boiler is giving up the ghost.

If your boiler keeps losing pressure and you can’t identify the cause, it’s best to have it checked by a professional – they may be able to find and fix the problem straight away, or advise you on the best course of action to take.

If you do need a new boiler, then don’t delay – have a new one fitted before January and February bring the coldest temperatures of the year along with them. You can get a free quote from WYGS online today just by filling out a few details – click here to find out more