Absolute mystery

[Daveleaver]

Evening all

So... had a new boiler fitted and pressure keeps dropping i called the guy back and we isolated the boiler from the rads at 1.0bar 36 hours later no change so i opened the flow and return and the pressure dropped to 0.8bar. So i have a leak on my paperwork simple yeah? Now this is where it gets strange.

I carried out the test again pressurised to 1 bar and isolated. Went back next morning 12hrs and pressure was the same until i opened the flow pipe and it went to 0.8bar

Carried out the test again same as above but this time re opened the flow and retuen in 3 hours and you guessed it 0.8bar again

So i decided to fill up to a bar and drain a rad until the boiler showed 0.8bar so i then coulf see how much water im losing i got 600ml out and as the 1st 4m or so of my pipework is 22mm i calculated that to be aboit 2m worth of pipework where the leak roughly woild be as its obviousky not leaking past this point.

If i leave the flow and return valves open on the boiler it will reach 0 pressure as its obviously feeding the leak.

My boiler is in the loft which gives me the conclusion my leak is around 2m down the flow pipe from the boiler. I can see the 1st 4m of pipework and its bone dry lol.

My question is is my assumption its on the flow pipe bull as when i drained the rad down manually or when it gets to 0.8 from the leak could that also be on thw return pipe? For example qhen i drained the radiator what pipe is it taking water from or is it about the same on both pipes

Thanks

Dave

 

[tolly]

Is it a combi? Or do you have a vented cylinder aswell, could be a split coil if you do.

It wont narrow it down to be the flow just because you open the flow iso underneath and that drops, its still connected to the return so its still testing that at the same time.

 

[Daveleaver]

Is it a combi? Or do you have a vented cylinder aswell, could be a split coil if you do.

It wont narrow it down to be the flow just because you open the flow iso underneath and that drops, its still connected to the return so its still testing that at the same time.

Hiya its a combi yeah. So it could be if im draining 600ml of water out to drop 0.2bar of pressure same as leak is doing it could be down either run of pipework?

 

[Daveleaver]

Whats baffeling me the most is its been doing this for round 3 weeks if thats 600ml isolated its over 3litres when un isolated i.e normal operation why would that not show up in my house

 

[joni os]

With boiler off,pipework cold. Pressure system to 2.5 bar and look for leak. Evaporation on hot pipes can conceal leak. Keep pressure between 1.5 & 2.5 bar until leak found.

 

[tolly]

Whats baffeling me the most is its been doing this for round 3 weeks if thats 600ml isolated its over 3litres when un isolated i.e normal operation why would that not show up in my house

Wont necessarily show up straight away if the leaks on the ground floor and its a timber or floating floor construction.

 

[Daveleaver]

Wont necessarily show up straight away if the leaks on the ground floor and its a timber or floating floor construction.

Yeah thats the issue my house is concrete sub downstairs with porcelain tiles and brand new carpet lol. Im adamant the leak is high up due to the results of my tests as my understanding is if leak was downstairs when i open the gate valves on flow and return it would just shoot to nothjng.

Am i wronf? Im no plumber

 

[PlumbBobBob]

you're wrong, sort of. it would only go straight to zero if there were an open end. the leak could be anywhere on your system really.

 

[Daveleaver]

you're wrong, sort of. it would only go straight to zero if there were an open end. the leak could be anywhere on your system really.

Hi

Sorry for late reply. What im confused about is as i have the boiler isolated im not allowed water back down the flow pipe. Now when i un isolate it and it drops to 0.8 the reason i think the leak would be high in the system pipework is purely just on the basis that im thinking if it was lower say downstairs surely more water would be lost therefore when un isolating the flow and retun the pressure would drop much lower if not to 0.

I want to repipe to whole house but the mrs doesnt want the mess as its just been all refurbed. I left the boiler isolated since posting this and just opened it now and its only dropped to 0.8 again it littrrally trickles down the flow pipe and you can feel it grt colder with your hand on it. Its a 3m run horizontally before dropping down in the cupboard im so confused and re pipong does seem a tad extreme considering gravity if the leak was lower surely more water would drop no?

Please help me understand its driving me insane lol. I ripped the bathroom floor up last night and can see all the joints are fine before going down the soil stack down stairs and had water in as they were much colder than the flow pipe in loft. Also bled the rad and just got water.

 

[Best]

Doesn't matter really what height on a sealed system you have a leak, - it will be much the same pressure. Gravity has really nothing to do with it on a sealed system.

 

[mfgs]

Forget what you are thinking, it doesn't make any sense. The leak could be anywhere on the system. The fact it isn't showing yet means its more than likely on the ground floor or you would start to see staining on walls or ceilings. You could try a thermal imaging camera and run the heating and see if there is a larger area of heat near any pipework in the ground floor.

 

[king of pipes]

Boilers in lofts are apita this is the highest part of the system the auto air vent in the boiler may be letting by get the inside of the boiler checked for any signs of leakage ,soon as theres the slightest drop in pressure it will suffer i suggest you get your installer to add extra valves to the system so you can isolate sections of pipework to narrow down where you have trouble dont rely on the pressure gauge on the boiler i always put a gauge and fill point on a lower floor best of luck k.

 

[Daveleaver]

Boilers in lofts are apita this is the highest part of the system the auto air vent in the boiler may be letting by get the inside of the boiler checked for any signs of leakage ,soon as theres the slightest drop in pressure it will suffer i suggest you get your installer to add extra valves to the system so you can isolate sections of pipework to narrow down where you have trouble dont rely on the pressure gauge on the boiler i always put a gauge and fill point on a lower floor best of luck k.

I get my thoughts seem a bit like whaaatt lol. Basically am i incorrect in saying if i had a leak lower down why would it not empty the pipework upstairs

 

[rpm]

I get my thoughts seem a bit like whaaatt lol.

Well done Dave, so many people come here and wont or cant listen to experience. :clap:

 

[Daveleaver]

Well done Dave, so many people come here and wont or cant listen to experience. :clap:

Hey, its not meant like that my plan is to repipe. Im just looking to help understand why that wouldnt happen? Im not being rude so if you took it that way i appologise im just looking to understand.

Like i took some fittings off uostairs once it had done its pressure loss (a lot of them are speed fit) and the pipes had water in them so i was struggling to understand if the leak was downstairs why that pipe would still have water inaide

 

[rpm]

Hey, its not meant like that my plan is to repipe. Im just looking to help understand why that wouldnt happen? Im not being rude so if you took it that way i appologise im just looking to understand.

No apology needed Dave, didn`t think you were rude at all.
Same words and different meanings I guess eh?

 

[rpm]

Hey, its not meant like that my plan is to repipe. Im just looking to help understand why that wouldnt happen? Im not being rude so if you took it that way i appologise im just looking to understand.

No apology needed Dave, didn`t think you were rude at all.
Same words and different meanings I guess eh?

 

[rpm]

Like i took some fittings off uostairs once it had done its pressure loss (a lot of them are speed fit) and the pipes had water in them so i was struggling to understand if the leak was downstairs why that pipe would still have water inaide

Problem with plastic piping is that it is easy to have dips and rises in it giving the impression that the pipe is full of water. Maybe, just maybe this is the case here.

 

[Daveleaver]

Hiya
Thanks guys. No prob. Sorrry should have said better the connectors are push fit all the pipes are copper. Shall i take some pics for you? Can i upload them here never tried

 

[Daveleaver]

Hiya
Thanks guys. No prob. Sorrry should have said better the connectors are push fit all the pipes are copper. Shall i take some pics for you? Can i upload them here never tried

 

[Daveleaver]

 

[Daveleaver]

 

[Daveleaver]

Push fit city lol so yeah the picture of the pipes going under the cover they run all the way up to yhe loft into a push fit elbow then a 3m run each to the boiler. Its this 3m pipe tje flow that emptys.

Under that cupboard cover all the pushfit you can see is full of water confised why i have 1 flow pipe going yo the bathroom and 2 returns lol. But that besides the point. All the rads in this house are compression fittings too.

But yeah basically pressurised to bar isolated for a week then started tsking those connections ofg and water everywhere lol i put a tub underneath 1st. But yeah its just made my brain explode tbh. No matter how long i isolate it for same amount of loss and thays what i meant i just thoought ah good leak must be high cos itherwise itd all drop out cos water goes down but no idea now

 

[mfgs]

if its an 0.8 bar it will still all be full of water. You take any joint off and there will be water. When its at 0 then you may have no water or may still have some depending on what point of the system. Unless you have water gushing out you aren't going to have an empty system, you yourself said earlier it only took a small amount of water to lower from 1.0 to 0.8, so why are you expecting pipes to be completely drained of water?

The noise you hear when you open the isolation valves is it pressurising, not filling

 

[mfgs]

if its an 0.8 bar it will still all be full of water. You take any joint off and there will be water. When its at 0 then you may have no water or may still have some depending on what point of the system. Unless you have water gushing out you aren't going to have an empty system, you yourself said earlier it only took a small amount of water to lower from 1.0 to 0.8, so why are you expecting pipes to be completely drained of water?

The noise you hear when you open the isolation valves is it pressurising, not filling

 

[Daveleaver]

Afternoon

Sorry for late repky been working my a××× off lol yeah i hear ya on the pressure thing when its isolated and ive left it a while the flow pipe in the loft going to the cupboard 3m is empty i can take it right out the joint

 

[Daveleaver]

Afternoon

Sorry for late repky been working my a××× off lol yeah i hear ya on the pressure thing when its isolated and ive left it a while the flow pipe in the loft going to the cupboard 3m is empty i can take it right out the joint

 

[Simon F]

when you isolate the boiler you are isolating the expansion vessel!

the pressure in the rest of the system will drop and loose water through the leak.
when the pressure has gone, which wont take long there will be no more leakage as the system is sealed.

when you open the valves to the boiler the pressure is then stabilizing at 0.8bar this will be due to the expansion vessel.
so when the valves to the boiler are open the expansion vessel will be pushing the leak and emptying the pressure down to nothing.

 

[Daveleaver]

when you isolate the boiler you are isolating the expansion vessel!

the pressure in the rest of the system will drop and loose water through the leak.
when the pressure has gone, which wont take long there will be no more leakage as the system is sealed.

when you open the valves to the boiler the pressure is then stabilizing at 0.8bar this will be due to the expansion vessel.
so when the valves to the boiler are open the expansion vessel will be pushing the leak and emptying the pressure down to nothing.

Right! Im getting somewhere now Simon thank you for taking the time to explain that to confirm i understand when isolated at the start its got a bar same as the boiler enough to push out the leak which dissapates quickly to the point where it wont leak aby more. When un isolated the expansion vessel is constantly applying pleasure which is forcing the leak out . Which therefore means my leak could indeed be anywehere.

Something strange happened btw i had to remove a radiator the other day downstairs as it was ij my way i drained the whole system down now when i have put everything back and pressurised its only dropped from 1 bar to 0.9 over night as assposed to 0bar