Silly Question ? i novice no clue

[wossie6]

I have a ariston microgen.23 combi boiler,(fitted new) i have all instructions etc,but there is no reference to the thing at the back (round contraption with a air valve on top,same as car tyres )what is this called ?
also i have depressed the valve and air escaped,what is the p[urpose of this ,and should there be air in it,if so does it need to be a certain pressure.

daft ques i know but its curiosisty.(its been on the wall five years now)

 

[silverback]

It's an expansion vessel, it should have air in it, it's purpose is to absorb the water expansion as it heats, the pressure will normally be about 0.5 bar, but do not try and take a reading with the system pressurised, this will give a false reading, the system needs to be empty to get an accurate pressure reading of the expansion vessel

 

[chrishutt]

i have depressed the valve and air escaped

You what?

Now your going to have to have the expansion vessel repressurised! This involves reducing boiler pressure to zero, attaching bicycle pump to air (schrader) valve, pumping up the pressure, attaching pressure gauge to schrader valve to check, repeating this until about 1.0 bar achieved. Then refill boiler and pressurise to 1 bar or a little above on the system pressure gauge.

Anything else you plan to fiddle with on the boiler?

 

[kevplumb]

i have depressed the valve

have to ask WHY ???

 

[wossie6]

lol
i depressed the valve for a micro second around 4 years ago.It was only reading through the plumbing section that got me curious.

but while your here how do i balance the heating,and how do i know whether or not trv`s are working.

got old looking valves(temtrol) with numbers written on but i dont know if they work. they turn but no resitance when turning.no markers for knowing what number valve is at .is there a quick and not so messy way of changing the trv`s without draining system ?

 

[Paul Barker]

Reminds me on the self important diy repair guy for a local static caravan site. Rang my mate up to complain about all the crap boilers (worcester) he'd fitted. When he got there man said, I've been round and bled them all, and now they keep leaking out of that pipe and need topping up all the time!

Wasn't you was it?

If the radiators get warm trv's probably working, if not, they need a good clout until they work.

Balancing is complexed there is a web page on it somewhere do a google search.