Expansion vessel question....

[Gunslinger]

ok, checked it this afternoon.....

1. First thing i noticed is the gauge was practically at zero on the front checked outside, and the pressure relief valve has blown open at some point overnight/today.... bugger
2. Checked the valve as instructed, no water, but also hardly any air, like less than when you open a coke bottle
3. Pumped up the vessel, about 6 strokes of a car tyre pump, no water on removal of the valve, didn't lose much air, and the gauge on the boiler moved up - looks like the hose is ok
4. checked pressure - 6psi - let a little out to check for water ... nothing
5. Pumped up the vessel to 10 psi - as said by someone, took about another 7-8 stokes, so 15 was a good guess
6. Pressure gauge came up accordingly to the added pressure in the system
7. Opened the fill valve to increase cold static pressure to 1 bar
8. waited a few minutes, and pressure is holding.
9. Turned everything back on (except heating controller) and pressure jumped up 1/4 bar initially, when everything settled down it was back to just above 1 bar.


so, it looks like the vessel was ok, just the air had depleted to virtually nothing over the last 14 years since it was fitted (don't know if it's ever been checked) i've put the heating back on and we'll have to wait and see if all is well now, will keep an eye on it and see, main thing that worries me is that if the PRV has opened, will it seal closed properly or is it going to constantly sweep now ? i have a bucket outside under the outlet pipe, so i should see if it dumps any noticeable amount out of there.

 

[petit_pablo]

Happy days

The pressure will drop again if the PRV is letting by and usually its a quite noticable amount of water thats drips out. Fingers crossed on that one as the PRv is an arse to remove on these

 

[Gunslinger]

yeah, i just had a look at it wondering about that, and your right, the whole boiler design looks horrible from every view point i looked at from electrical to pipe routing ... not good

pressure seems to be holding, i have a bucket outside so i'll keep an eye on that (bricks were noticeably wet earlier, and no it hadn't rained !) ... but i did forget to put a cover on the bucket ... doh!

all i can do is monitor the gauge as the boiler gets used more, at the moment unless i kick it in manually its not needed to heat the rads yet, and to get the temp and pressure up high, i'd need to run off a lot of water, but yes as you said, fingers crossed and happy days


Thanks for the help guys

 

[Gunslinger]

Update

Lost half the pressure in the boiler over night
Dont know if it's the PRV or not, it ****ed down here last night, i knew i should have tied a carrier bag to the pipe outside ! (although finding one without holes these days is almost impossible!)
I'll turn the top on the PRV a couple of times and see if i can get it to re-seat properly (assuming that is the issue)
Going to recheck the pressure vessel today too, just in case, and, knowing my luck, i better take a walk around the loft and make sure i havent got any wet patches !

Nothings ever easy is it

 

[doitall]

You need to check the vessel with the system charged to 1 bar ish.

Put a balloon over the outside pipe to check for drips.

 

[Gunslinger]

yup, did that yesterday while i was re-pressuring the vessel, didnt get any water out of it then so i kind of assumed that if it was knackered then it would have leaked water immediately out of the valve .... but i will check again today

balloon... great idea

 

[Agile]

It will only leak when the CH cycles.

Top up to 1.5 Bar with rads cold and it should only increase to about 1.8 Bar when hot.

If you dont have a baloon then you can use a condom.

Tony

 

[doitall]

It will only leak when the CH cycles.

Top up to 1.5 Bar with rads cold and it should only increase to about 1.8 Bar when hot.

If you dont have a baloon then you can use a condom.

Tony

Good idea Tony, waste not want not, always keen to recycle.

The pressure will rise according to the system size in relation to the vessel size.

 

[Gunslinger]

right, span the top on the pressure relief valve a couple of times, and it seems to be getting stuck, resulting in water peeing out even after it's clicked back, ended up with a lot of air getting into the system too at this point, and i could hear the water draining out of the system from the rads above.

i did not seem to lose any more pressure from the system before i did this, but it's been switched off. I'm now wondering if i didnt have enough expansion space behind the expansion vessel when i re-charged it giving me a false reading, thus making it useless with the system warm and the pump running.

i'm done messing with this piece of rubbish now, it can stay off until my plumber gets back and can sort it, if it needs a new PRV, vesssel and hose then fine, i'm fed up with freezing my ass off, or not trusting the thing to do the job it was built for ... and it has done nothing to improve my views of combi boilers whatsoever