Loss Of Pressure On Your Boiler?

A loss of pressure in a boiler system is one of the most common problems that arise with household boilers. There are several reasons why this could be happening and some of them you will be able to rectify yourself before you call out a plumber. However, if it is happening quite regularly then it is likely you have a more serious problem and should contact a plumber.



Once your boiler drops below a certain level, generally around 0.5 bar it will knock off your boiler and you will lose hot water and central heating, which is not ideal at the best of times. When your boiler is not on and is cold, the pressure needs to be around 1 bar and 1.5 bar when running. Anything close to that is fine.



The first thing to do to get you out of trouble is to top up your boiler through your filling loop. This is basically a link from your cold water to your central heating and allows you to fill it up with water. They come in all different shapes and sizes so make sure you are confident in what you are doing as doing this incorrectly can lead to other problems. By turning both levers, you are can top up the boiler pressure, keep an eye on your gauge until it reaches 1-1.5 bar. Once you hit that point turn off both levers. Topping it up too high is going to cause problems so avoid that!


Why is your boiler losing pressure?

Identifying the problem


1. Leaks on your central heating



A common cause is a leak on your central heating, and it is more than likely coming from a radiator valve. So, go round all your radiators and make sure none of them are seeping water. If one is and you are confident, give it a tighten with a spanner. It may also be possible that there is a leak on your pipework under your floorboards, have a look for damp patches on your ceiling. If this is the case, call a plumber as they will have to locate it and repair before it causes anymore damage!

2. Pressure relief valve



The Pressure relief valve is a safety feature on your boiler. If your boiler has too much pressure in the central heating system, it will discharge out of the red levered valve to the outside of your building. Sometimes, the valve passes water and will slowly drip while your system is running. Over time it will drop in pressure and your boiler will fault, losing your hot water and central heating. To check this, go to the back of the boiler on the outside wall and look for a copper pipe that turns back on itself. If there is a slow drip the likelihood is that you need a new pressure relief valve and will have to call a gas safe registered engineer.

3. Expansion vessel



Your expansion vessel is a component that may be situated either internally or externally on your boiler depending on what type of system you have. In short, the vessel is essentially a balloon which inflates and deflates with the expansion of hot water in your central heating system. The vessel should be checked annually when you have your boiler serviced and should be at a pressure of 1 bar when cold. Over time the balloon inside the vessel can perish and in turn loses that room for expansion in your system. While you have your central heating running the pressure will rise too high and it will discharge again out of the pressure relief valve. It is a common part to develop a fault and you will need a gas safe registered engineer to replace.

4. Main Heat exchanger


The last and most unlikely cause would be your main heat exchanger. If your heat exchanger has split and is leaking, then it can be a disaster. It is always worth checking to see if your boiler is under warranty as this is the most expensive part on the boiler to replace. If your boiler is old, then it might be worth considering getting a new one. Contact a gas engineer to put you in the right direction. Repairs are not always the most cost effect over time.


Key Notes

● Your boiler is just like your car and should be serviced every year to avoid faults occurring.

● When you notice something, deal with it sooner rather than later as it can lead to other faults in your boiler.

● Your central heating system should always be topped up with inhibitor to avoid rust. If it is not, this can lead to the water in your system turning black which can lead to cold patches in your radiator.

Anybody working on your boiler should be gas safe registered, call Pulse Plumbing & heating ltd anytime. We are here to advice and put you in the right direction.

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