re-charging expansion vessel

[aeu99217]

Hi,

I posted earlier about issues i'm having with my combi boiler. I had replaced the pressure relief valve but was then having the pressure increase. I was advised to re-charge the expansion vessel which i did (hoping i had done it correctly) and thought it had fixed it. However, the pressure is still increasing but alot slower than before.

I'm wondering if i maybe did something incorrectly.

firstly i cut all the pipes off and then drained the boiler using the drain cock. Next i attached a pump with gauge to the expansion vessel and pumped. When no more water came out i closed the drain cock and then pumped until the reading sat at 1 barg. Then i unattched the pump, opened up all the pipes and re-pressured the boiler before finally turning it on. This seemed to work as the pressure stayed within range recommended (1-1.5 bar) however over a period of a couple of hours it has inched up to 2.5 bar while the central heating was on.

Did i do something wrong? should i have left all the pipes open? is the improvment in the speed of the pressure increasing suggest that i maybe didnt pump enough into the expansion vessel?

Any help would be greatly appreciated.

Thanks

 

[doitall]

Where did you pump the air, in the Schroeder valve

 

[kevplumb]

When no more water came out i closed the drain cock and then pumped until the reading sat at 1 barg.

leave the drain tap open when you repressurise the ex v

 

[aeu99217]

if the Schroeder valve is the 'car tyre' like valve that sits on top of the expansion vessel, then yeah. Very difficult to get to cause of its location. I bought a wee foot pump with a pressure gauge and each time i 'pumped' into it the gauge would rise before falling down, but the 'baseline' (so to speak) did rise each time.

 

[aeu99217]

the reason i closed it was because it seemed like it was taking forever. the boiler is a vokera 20 - 80 rs flowmatic, if this makes a difference.

I'll try it again tomorrow after work. But this time leave the drain cock open? what about the other pipes (ie return pipe, etc) should i be closing them?

Thanks Again

 

[kevplumb]

yes close flow and return

how to

 

[aeu99217]

excellent, thanks for the help