Sealed system slowly pressurizing when filling loop AND stopcock turned off.

[RoyalCrabs]

Hey guys,

Before I start I'm just stating ; This is merely a QQ, I am not about to commence work on it, I am just inquiring on a situation that is happening at a friends house down the road who has the plumber who installed the system (and I believe is qualified .. ) en route to fix the issue.

Popped over to see a friend of mine who was having the annual boiler service when I arrived, he said it was constantly but slowly pressurizing BEFORE he started work (which is apparently true as the same noise had been going on for months..).

The filling loop was already 'off', then he tried the stopcock and it was STILL slowly filling.

stopcock ON and filling loop ON - Quickly pressurizes as it should.

stopcock ON and filling loop OFF - Slowly pressurizes.

stopcock OFF and filling loop ON - Slowly pressurizes.

stopcock OFF and filling loop OFF - Still slowly pressurizes.

The heating engineer gave up and said to get the installer out to fix the issue as he had no idea what to do either..


Now, its been a while since I was in training but when you turn the filling loop OFF ... It should stop bloody filling up?
I know I'm making myself look like a complete and utter n00b but just a bit confused on this one.

 

[village idiot]

You are allowed to get confused -, but the Heating Engineer, he should go and retrain.
Have the filling loop changed. Goes to show why manufacturers advice the filling loop to be disconnected after commissioning.

 

[RoyalCrabs]

Haha, I knew that the loop was letting by slightly, I told them to change that a year ago.. But why on earth would it still fill with the Stopcock turned off?

 

[mcniven]

stopcock passing theres no other answer

 

[village idiot]

What is to say the stop tap is not letting by as well?
With the stopcock closed, are any taps usable (flow of water)?
With you there to help your friend, ask him/her to change stopcock and filling loop

 

[mcniven]

Obviously im presuming the pressure is rising when heating is OFF , if filling loop is off and stopcock is off and the boiler is pressurising .. The filling loop is faulty and so it the stopcock.

 

[RoyalCrabs]

Yeah heating was left completely OFF by the engi.

I did test the kitch tap and turned off the stop.c (VERY tightly) and it was bone dry, however, the stop.c is in the cudboard where the boiler is installed so with them BOTH letting by the pressures gonna go to the nearest appliance ; the boiler.

I'm waiting to see what their 'installer' says in the next hour...
You guys most probably nailed it but I'm curious regardless !

 

[dave1]

Presuming the stopcock doesn't isolate the boiler and only the filling loop, if its a combi could be a pin hole in the plate heat exchange.

 

[sneds]

Whats the name of the boiler you have in ?

 

[RoyalCrabs]

I cant remember I didnt actually check.

Their installer said 'pretty much the same', however he couldnt find the outside stopcock to the house.. and buggered off leaving the inside s.cock turned off and said 'contact the waterboard'...

 

[village idiot]

since you say you want to help your friend, go back there (with the stopcock still in the turned off position as left by the ''Installer''), place a towel etc around pipe as close to old stopcock as possible, then cut pipe and fit a new stopcock. Job done.

Outside stopcock may be feeding more than one house in some areas.

 

[Ray Stafford]

I did test the kitch tap and turned off the stop.c (VERY tightly) and it was bone dry, however, the stop.c is in the cudboard where the boiler is installed so with them BOTH letting by the pressures gonna go to the nearest appliance ; the boiler.

This confused me. With a tap open, any water passing the stopcock should have come out of the tap surely? Its a path of considerably less resistance than increasing the pressure in an already partially pressurised heating system.

 

[RoyalCrabs]

I know.. It is why I had to check, double check and triple check as to what in the name of fork was feeding the boiler..

But you learn new things every day right?

 

[sneds]

are you sure its the mains stopcock and not an additional one installed to control a draw off some where i.e kitchen, bathroom ??

 

[RoyalCrabs]

I am almost certain of it, theres just the kitch. bathroom and loft cistern (small bungalow) I cannot see what else there is to isolate

 

[sneds]

Filling loops should be disconnected anyways, should only be connected to top up the pressure !

 

[sneds]

almost certain of it ??? knock on the neighbours door and ask where their stock cock is, 99% of the time your m8s will be in the same place !
The reason i ask is because i have had call outs by customers saying that they have a leak in the kitchen and tried turning the stopcock off and its not stopping, only to get there and it wasn't the mains stock cock they were turning off, but an additional stock cock fitted to isolate bathroom.
Phone about for a decent plumber m8, it save you alot of money, it will not take them long to fit a new stop tap.

 

[RoyalCrabs]

Heck I can do it myself I just cant be bothered with stepping on the toes of the other plumber and heating engineer arguing between themselves.

Like I say I'm almost certain as theres no other stopcock within the house, comes up through the floor (into cudboard containing the boiler), T's off going back down through the floor (presumable to feed the kitchen), then vertically up, T'ing off again for the filling loop and then through the ceiling into the Attic where it feeds the Cistern. The HWSV was relocated into the attic also.. so its all kinda local. They're at the end of a cul-de-sac so theres no other logical place where -another- stopcock would be..

You could be right though.. Again, sittin 'n waiting to hear whats going on over there.

 

[Ermintrude]

Does pressure rise slightly or does it continue when stop tap is off? If the system is sealed and no passing stop tap say 6 bar, you open filling loop and confined water in DCW system equalises with that of the CH, net result slight rise in the ch system originally at 1.25bar ?

 

[wattsie1987]

Does pressure rise slightly or does it continue when stop tap is off? If the system is sealed and no passing stop tap say 6 bar, you open filling loop and confined water in DCW system equalises with that of the CH, net result slight rise in the ch system originally at 1.25bar ?

Possible in theory but not sure if it would as low closed DCW volume, I think it will equalize rapidly with no real movement on the gauge.

 

[goz666]

Can't understand why the heating engineer/plumber didn't disconnect above the mains stop tap to prove the theory....I couldn't have left without having a look !!!

 

[RoyalCrabs]

Their plumber was there for like... 5 minutes and couldnt find the outside stop.c and said to call the waterboard.

Yeah, to put it simply, a lot of my customers are his ex customers.