Leaking Boiler

Leaking Boiler

Do you've got a leaking boiler?

If you have a boiler that you may think is leaking, but cannot see any form of leak, what do you do?

First we must establish what type of boiler you have, could it be a mix boiler, system boiler or heat only boiler.

With combination and system boilers they work under high pressure, with heat only boilers they are sometimes are pressurised, or work under low pressure.

With all boilers which are pressurised you will see a pressure gauge suited to either the front of the boiler or near by on the pipe work.

A leaking boiler isn't always a leaking boiler, I know that may sound strange, but it's true. Each one of these boilers working under high pressure should have an expansion vessel fitted either internally or externally, this is normally the reason for a leaking boiler.

So how do we resolve the leaking boiler problem?

First you ought to have your boiler serviced each year without fail, in the event that you decide not to have your boiler serviced then at sometime in the foreseeable future you will have an expensive repair bill or even the cost of a fresh boiler.

So why is it important to have your boiler serviced?


The days of not bothering to service your boiler have over, these boilers were very basic and not much went wrong with them, the most common problem was that the thermal coupling had to be changed. These boilers weren't very efficient around 40% of one's fuel bill went of the flue and the other 60% into you're heating system.

Since the introduction of the high efficiency condensing boilers it has been very important to have them serviced every year. These boilers are designed to give the best performance and most of most save you on your own energy bill.

Whenever a boiler service is carried out we are looking first to be sure everything continues to be safe, that there are no combustion or gas leaks, checking on the flue making sure the merchandise of combustion are exiting to the exterior as they should.

We take a combustion reading with a combustion analyser and check that the boiler when running is within the boiler makers parameters, if the reading aren't correct then we perform further investigation to find out why, then reset.

Next we come to the most frequent problem with these boilers.

The expansion vessel, The expansion vessel is really a very important section of your boiler and heating system, if this is not working properly you then will have problems. The most typical problem will be the loss of system pressure, a lot of people describe this as a leaking boiler.

In fact it's not a leaking boiler, it's an expansion vessel problem. The vessel should be checked each year and reset for the boiler to give its best performance, when the vessel it not checked, over time it will stop working.

The Boiler Service

When you call in your neighborhood gas safe registered boiler service engineer to service your boiler, ask him to make sure the expansion vessel is checked over and reset if needed. For some reason when a boiler service is carried out, the expansion vessel is apparently left out rather than checked, not all of that time period but around 80% of the time. When you read the boiler makers instructions on boiler service they state that the expansion should be checked and reset if needed.

So what happens to the expansion vessel?

The simplest way to describe the expansion vessel is, its like a car tyre, as time passes it will eventually go flat. The vessel is the same, it is pumped up with a car pump to a Pressure that is compatible to the sort of heat you have.

If the vessel loses its pressure then it will begin to fill with water internally, once this starts to occur most people begin to think they may have a leaking boiler.

Boiler servicing Colchester  by taking on the expansion of the water since it heats up within you're heat. If the vessel does not have any internal pressure then it will fill up with water, once full, your boiler will then start to discharge water through the pressure relief valve, release a the pressure to avoid pipes bursting.