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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> problem with possible leak (help) https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1288880579 Message started by paul n on Nov 4^th, 2010, 2:22pm

Title: problem with possible leak (help)
Post by paul n on Nov 4^th, 2010, 2:22pm

over the last few weeks i have noticed a rather dramatic pressure loss on my boiler system which is a vokera mynute 20e. i have a maintenace type agreement with my utility provider (hydro electric) and have had three visits from them in the last 10 days. of which they replaced a valve and fiddled about

on the last visit the said it must be a leak under my floor (solid wood) which i layed throughout my lower level and stated if there was a leak elsewhere it would have showed. the system pretty much keeps stable whilst powered on and hot water is running but when switched of it drops 1.5 bar every few hours

i did have my garage converted in the last year of which they said it was more than likely that which was the problem as the original radiator was relocated to do this. i have removed the solid floor from both sections which is ruined to find no evidence of the leak and after another visit i am told it must be somewhere else

i did try ferox sealer also to no avail as they recommended this as alternative although i have had to buy this myself and proved fruitless and the insurance company will neither replace floor or locate leak and tbh i am about at breaking point with this

the floor has no depth to check underneath and is pretty much a concrete slab with the radiator pipes clipped onto it foam insulation and two inch batton, chipboard and the wood flooring

i contacted a few companies that specialise in thermal leak detection but they want £500-600 for a 2hr survey which only is 90% successfull and i do not have the money for this

if anyone can throw me any ideas i would gladly appreciate it

thanks in advance for taking the time to read this

Title: Re: problem with possible leak (help)
Post by CWatters on Nov 4^th, 2010, 4:57pm

wrote on Nov 4^th, 2010, 2:22pm:

the system pretty much keeps stable whilst powered on and hot water is running but when switched of it drops 1.5 bar every few hours

Did they check the expansion vessel?

Try this...

Allow system to cool
Repressure to normal setting
Turn on heating and watch what happens to the pressure.

If the pressure rises up to say 3bar and water comes out of the pressure relief valve then the expansion vessel is likely to be the problem. Could be faulty OR simply too small now that the system is bigger after the garage conversion increased the volume.

Edit: The fact that the pressure falls when the system goes off is also a clue that this is the problem. I think it's unlikely t be a leak if the pressure is stable while the heating is on.

Title: Re: problem with possible leak (help)
Post by paul n on Nov 4^th, 2010, 8:18pm

thank you for your reply

if i fill to 1.5bar cold it stays the same does not rise when heating on but runs pretty stable until when turned off when it takes a big drop over short space of time

Title: Re: problem with possible leak (help)
Post by CWatters on Nov 5^th, 2010, 12:14am

Does any water coming out of the PRV or is it allways dry?

Title: Re: problem with possible leak (help)
Post by thescruff on Nov 5^th, 2010, 3:38am

Turn the boiler off, and pressure the system to 2bar, next turn the 2 heating pipe valves under the boiler off.

Leave overnight or for several hours, check the boiler pressure hasn't dropped, and turn the valves back on, if the pressure then drops you know it's the system that has a leak.

Title: Re: problem with possible leak (help)
Post by paul n on Nov 5^th, 2010, 6:51am

the prv is dry pipe is dry

i will try the isolation valve today and see if there is a drop on it

just a question regarding the 2 valves which you say turn off, i have three pipes to boiler gas inlet, heating flow and heating return

do i close both heating flow and heating return after filling to 2bar???

thanks again for your responses

Title: Re: problem with possible leak (help)
Post by paul n on Nov 5^th, 2010, 8:47am

i have closed the valves and it has dropped half a bar in 30 mins

any suggestions please ???

Title: Re: problem with possible leak (help)
Post by CWatters on Nov 5^th, 2010, 1:22pm

Does sound more like a leak.

How about installing valves so you can isolate the upstairs and downstairs from each other. That would help narrow it down and might mean you could have some of the heating on while you locate it.

Title: Re: problem with possible leak (help)
Post by thescruff on Nov 5^th, 2010, 4:27pm

wrote on Nov 5^th, 2010, 8:47am:

i have closed the valves and it has dropped half a bar in 30 mins

any suggestions please ???

I assume you mean it dropped with the valves shut, if that is the case you have a leak in the boiler.

Check the condensate pipe to see if it is dripping/running with the boiler off.

Title: Re: problem with possible leak (help)
Post by paul n on Nov 6^th, 2010, 9:18am

yes it dropped with the valves closed

had a visit from hydro engineer and he simply discarding the valves as possibly letting the water run through still, despite me explaining the valves were fully closed

i did timings and the system runs from 2bar to 0 in 3hrs with both the valves open and closed

no evidence of water leak from inside boiler and the insulation pad are bone dry etc and cannot see any other signs of water loss

any other ideas please ???

Title: Re: problem with possible leak (help)
Post by thescruff on Nov 7^th, 2010, 12:05am

If the boiler is dry inside then the valves can't be fully closed, unless the PRV is leaking.

Tie a plastic bag over the copper pipe that sticks through the wall to outside.

Title: Re: problem with possible leak (help)
Post by paul n on Nov 7^th, 2010, 8:10pm

just a wee update and a question also =

ripped up my floor (crying) a lot of it is knackered and the walls are a mess with ripping skiting off also

when i got the floor up to third radiator i seen wet chipboard lifted the section up and it was soaking underneath. i then traced the water loss to the connection nut at the radiator rise pipe and it was slightly dribbling water down the back of the pipe

i have got my adjustable grips and gave it a tighten and hey presto sorted kepping pressure on the boiler now !!!

i am now rageing as hydro has told me the leak was under the floor and everything was checked including the rads and if they had checked properly this could have been spotted without costing me £100,s of damage and also costing me 5 days off work and an untold amout of stress on me and my family who is having to stay at a relatives due to the state of the house

i am really considering claiming them for compensation. does any of you experienced people out there think i have a chance as this quite clearly could have been spotted should people have done their jobs properly (please bear in mind i have had 7-8 visits of which this could have been spotted)

Title: Re: problem with possible leak (help)
Post by thescruff on Nov 7^th, 2010, 8:31pm

The first thing to do is check all the valves and everything above ground by simply running your finger around the fittings/pipe.

If that wasn't done they ain't done their job properly.

I had assumed you would have done that in any case.

Title: Re: problem with possible leak (help)
Post by paul n on Nov 8^th, 2010, 8:18am

in hindsight it was stupid of me not to double check and can only say in my defence that the told me they had checked all the radiators etc