Pressure drop (I know...)

[MickyP10]

Hi guys

Have a 5-year-old Firebird oil burner and pressursised system and it's just started losing pressure. This happened a couple of years back and after doing all the above ground things, I found a leak from a pipe under the (laminate floor) and in the screed. (Yep, it was around Christmas time!) Utter bastard of a job. Obviously, with laminate flooring, it's extremely hard to pin-point leaks. Before it gets to floors up, though, a couple of things. Can AAVs lose pressure without physically losing water and can I tighten up the bleed vents for a couple of days to see if things improve? Also, have a couple of AAVs on towel rails. Can they lose pressure, too? Again, cannot see any leaks.

Did initially find the pressure vessel had lost some pressure (down to 15psi), so re-pressurised and now everything's fine when it's hot and pressure's up, but overnight when it cools, the pressure seems to drop. Pressure vessel seems to be holding pressure so I assume that it is fine. Have just bought but not installed a leak sealer. Are these any good? And, assuming it is a connection under the floor, is this going to continually re-occur until I have a coronary?

Edit to say can't see any drips or owt in overflow.

Thanks for any advice you may be able to offer.

Mike

 

[Burnerman]

AAV's and other bleed devices can certainly weep, and sometimes the water can evaporate almost as quick as it leaks...but there will always be a trace of salts deposited.
How much pressure do you lose overnight? Did you replace the pipe that was leaking last time? Not nice having to take floors up.
John

 

[MickyP10]

Ah, well cannot see any signs of weepage from AAVs, and PRV is bone dry. Was thinking of just replacing them and the pressure vessel but TBH think I'm just putting off the inevitable.

Pressure drop, which has slowed since re-pressurising PV, is, maybe, 4-6Ibs a night. But then we've just had a cold snap and that may be influencing things.

Yep, replaced the pipe last time. The worry is, whatever I do now, and clearly if it's removing the flooring and digging up the screed, which I don't want to do, it may well happen again 18 months from now. Which sort of leads me to getting a bod to run new pipework above ground. Wifey's pulling a funny face, of course, but then ripping up the flooring ain't funny either!

Do leak sealers work at all? Or are they a temporary thing? The one I just bought was £22!

 

[Burnerman]

A pressure loss like that is significant....are there any other pipes buried in screed? If they are, its only time before they go the same way - unless they are properly protected, of course.
Personally I wouldn't go for a leak sealer...its maybe ok for a tiny unfindable leak maybe, but not in your case.
Hope the leak isn't too hard to find! Big shame to rip flooring up.
John

 

[MickyP10]

They're wrapped. Well, the leaky one seemed to be wrapped but, even so, it leaked! What would a reasonable quote be to re-pipe it above ground? Last floor-up job was two grand!

Edit to say this is a 5-bed bungalow.