any heating engineers on here

[2512pf]

help I have a 8 year old bosch combi boiler and water pressure keeps dropping,but I cant find a leak anywhere ?? so where is the water going to

[Ray]

my heating engineer tells me that 7-8 years is now about the rough manufacturers life for a combi, and sure enough ive had 3 fitted in 18 years, because after that point the manufacturers of the first 2 were refusing to support with spares

 

i have a bosch one now, and its been repaired for that once, which was a cracked joint in the filling loop, the boiler kept loosing pressure, but no leak could be found until one day it flooded out, as the water was evaporating while there was heat being generated

 

ours is a condenser boiler and there is a water tank in the boiler, that aids the speed of which you get hot water, (dont ask me how it all works, i just know its there) we have also had this leak, and aparantly is a common fault as well, again, leaks and evaporates or leaks at the back where you dont see it, till one day you have a flood

[2512pf]

thanks ray I think I will just get a couple of quotes for a new one

[2.1CORTINA]

Hi, the expansion vessel is likely depressurised and may have back filled with water. It works in the same way as the expansion side of your car radiator/water system. When the heating is turned on and the water heats and expands, rather than the pressure rising to the point that the pressure relief valve opens (3bar), the water expands and compresses the air within the expansion vessel.

To recharge the expansion vessel you need to create an open end on the system, i.e. open a drain off or even open a radiator vent/bleed.

Then locate the Schrader valve on the expansion vessel and attach an air pump with a gauge. As long as the pipe that connects the expansion vessel to the heating isn't blocked ( worcestor don't normally have an issue), start pumping and when your air gauge reaches 1 bar and stays there, you know your no longer pumping water out of the expansion vessel.

Remove the air pump and make sure the schrader valve isn't letting by.

Shut the open end on the system.

Repressurise the boiler to 1 bar, run the heating and vent the radiators, re-pressurise if necessary.

It would also be beneficial to check the pressure relief pipe where it terminates. This will be a 15mm pipe that will terminate outside.

 

If you don't want to do it yourself, any decent heating engineer can check/sort this.

 

Do not buy a new boiler. I carry out this work on a daily basis.

[2512pf]

just tried this and all seems to be good top man

[2.1CORTINA]

Great stuff. It will happen again, its the same for all expansion vessels. They're normally good for a couple of years but you won't realise it needs doing until your in that situation where every time you run your heating the pressure drops.

[D-FENS]

Great stuff. It will happen again, its the same for all expansion vessels. They're normally good for a couple of years but you won't realise it needs doing until your in that situation where every time you run your heating the pressure drops.

What part of the country do you cover mate ?

[2.1CORTINA]

I work in cornwall. But not self employed.

[Vista]

help I have a 8 year old bosch combi boiler and water pressure keeps dropping,but I cant find a leak anywhere ?? so where is the water going to

You could try Abbi Plumbing and Heating

[2512pf]

hi thanks but sorted now