Calling on any plumbers for assistance/advice 

Apologies for the long post in advance

I've just had a Biasi Riva Conpact HE (28kw) boiler installed along with
8 new rads,
pipework used was HEPA2 10mm runs around the house with either 15mm
copper or microbore ends.

All done as part of extension work and new pipework was connected to old
pipework feeding 4 existing radiators using 15mm copper pipes.

Since boiler commisioned, the pressure on the boiler kept dropping to
zero overnight, even though nothing in use (i,e, HW or CH), I found a
possible leak on a join from new to old pipework and that has just been
resoldered by the plumbers, but they did not stick around to check the
rest of the system, since they have gone the pressure is still dropping
dramatically and is visibly going from 1.5 bar to zero witin 30-60mins.

Any pointers on where to start looking, all new pipework is concealed in
walls and joists.
Could the boiler itself be faulty?, I have BG coming to do there annual
service check on Wed, will they be able to diagnose the cause?

Any comments/advice will be greatly appreciated

Thanks
Worried homeowner

Gaffar wrote:


> Any comments/advice will be greatly appreciated


The pressure relief/safety valve on the boiler sometimes drips. The
discharge pipe (15mm copper) will be piped through the exterior wall at
the boiler. You could fix a plastic food bag over it with a rubber band
to see if it fills up or gets blown off. It's a long shot though, with
a new boiler. Don't cap it or seal it in any way.

Other than that, you've got to play hunt the leak. You could get the
old pipewortk disconnected from the new. This won't help find the leak,
but if it's on the new system it's the Installer's liability & problem.
They won't deal with it whilst they can point a finger at the old,
suspect pipework.

You could also use the valves on the boiler (see Users' Manual) to
isolate the heating if it's a combi. Rad valves often drip around the
glands.

Aidan wrote:

> 
> Gaffar wrote:
> 
> > Any comments/advice will be greatly appreciated
> 
> The pressure relief/safety valve on the boiler sometimes drips. The
> discharge pipe (15mm copper) will be piped through the exterior wall at
> the boiler. You could fix a plastic food bag over it with a rubber band
> to see if it fills up or gets blown off. It's a long shot though, with
> a new boiler. Don't cap it or seal it in any way.


I don't think it is this as I have watched this whilst the pressure has
been dropping and nothing comes through

> 
> Other than that, you've got to play hunt the leak. You could get the
> old pipewortk disconnected from the new. This won't help find the leak,
> but if it's on the new system it's the Installer's liability & problem.
> They won't deal with it whilst they can point a finger at the old,
> suspect pipework.


If the pressure is dropping to zero rapidly, does that mean all the
water in the system is being drained somewhere?, if so should I not see
a wet patch somewhere as an indication as I have filled 
the system several times and it kepps dropping

Any tools/techniquies  that can be used to chase the leak?

> 
> You could also use the valves on the boiler (see Users' Manual) to
> isolate the heating if it's a combi. Rad valves often drip around the
> glands.


It is a combi, if the rad valves were leaking would I not see some
evidence of this on the floor
(there is no carpet yet)

Thanks for the reply

In article ,
	Gaffar  writes:

> Aidan wrote:
>> 
>> Gaffar wrote:
>> 
>> > Any comments/advice will be greatly appreciated
>> 
>> The pressure relief/safety valve on the boiler sometimes drips. The
>> discharge pipe (15mm copper) will be piped through the exterior wall at
>> the boiler. You could fix a plastic food bag over it with a rubber band
>> to see if it fills up or gets blown off. It's a long shot though, with
>> a new boiler. Don't cap it or seal it in any way.
> 
> I don't think it is this as I have watched this whilst the pressure has
> been dropping and nothing comes through
>> 
>> Other than that, you've got to play hunt the leak. You could get the
>> old pipewortk disconnected from the new. This won't help find the leak,
>> but if it's on the new system it's the Installer's liability & problem.
>> They won't deal with it whilst they can point a finger at the old,
>> suspect pipework.
> 
> If the pressure is dropping to zero rapidly, does that mean all the
> water in the system is being drained somewhere?,


No. The volume of water expelled (assuming no significant temperature
change in the water) will be something like half the volume of the
expansion vessel (depending on the air pressure in the vessel).
Probably around 4 litres, so you'll probably going to notice that
somewhere unless it's running into the ground under the house.
Does that seem like roughly the amount of water it takes to get it
up to pressure again? If not, then another possibility is that the
pressure vessel has failed, which would result in a very much
smaller volume of water leaking out and being required to refill.
This would also cause rapid pressure rise and pressure relief valve
discharge if water is heated up.

A quick look on the web implies this is a condensing boiler, in
which case another possibility is a leaking heat exchanger with the
water running out through the condensate drain, which might not be
obvious unless you have some way of checking it.


> if so should I not see
> a wet patch somewhere as an indication as I have filled 
> the system several times and it kepps dropping
> 
> Any tools/techniquies  that can be used to chase the leak?


When I installed my system, I fitted full-bore isolation valves
in the main branches, partly so I could isolate them to help
locate a leak if one happened (but mainly because I installed
half the system one year, and the other half the following year;-)


>> You could also use the valves on the boiler (see Users' Manual) to
>> isolate the heating if it's a combi. Rad valves often drip around the
>> glands.


Don't isolate the radiator circuit unless you switch off the
boiler. It may require it to dump excess heat when you switch
off a hot tap.


> It is a combi, if the rad valves were leaking would I not see some
> evidence of this on the floor


Yes. 

-- 
Andrew Gabriel

On 12 Sep,  
     Gaffar  wrote:


> Calling on any plumbers for assistance/advice 
> 
> Apologies for the long post in advance
> 
> I've just had a Biasi Riva Conpact HE (28kw) boiler installed along with
> 8 new rads,
> pipework used was HEPA2 10mm runs around the house with either 15mm
> copper or microbore ends.
> 
> All done as part of extension work and new pipework was connected to old
> pipework feeding 4 existing radiators using 15mm copper pipes.
> 
> Since boiler commisioned, the pressure on the boiler kept dropping to
> zero overnight, even though nothing in use (i,e, HW or CH), I found a
> possible leak on a join from new to old pipework and that has just been
> resoldered by the plumbers, but they did not stick around to check the
> rest of the system, since they have gone the pressure is still dropping
> dramatically and is visibly going from 1.5 bar to zero witin 30-60mins.
> 
> Any pointers on where to start looking, all new pipework is concealed in
> walls and joists.
> Could the boiler itself be faulty?, I have BG coming to do there annual
> service check on Wed, will they be able to diagnose the cause?
> 
> Any comments/advice will be greatly appreciated


If the expansion vessel is not pre-loaded to the correct pressure the amount
of water required to leak out will be small. Is a small amount of
water required to re-pressurise the system? If so, resetting the static
pressure in the expansion vessel may reduce the problem. A small leak can be
hard to find on a hot system due to evaporation of the evidence. Pumping it
up to maximum (usually about 3 bar) and looking for dampness around
joints/valves, whilst the system is cold, may find the leak.
-- 
  B Thumbs
  Change lycos to yahoo to reply

On Mon, 12 Sep 2005 18:48:14 +0000 (UTC), Gaffar
 wrote:


>Calling on any plumbers for assistance/advice 
>
>Apologies for the long post in advance
>
>I've just had a Biasi Riva Conpact HE (28kw) boiler installed along with
>8 new rads,
>pipework used was HEPA2 10mm runs around the house with either 15mm
>copper or microbore ends.
>
>All done as part of extension work and new pipework was connected to old
>pipework feeding 4 existing radiators using 15mm copper pipes.
>
>Since boiler commisioned, the pressure on the boiler kept dropping to
>zero overnight, even though nothing in use (i,e, HW or CH), I found a
>possible leak on a join from new to old pipework and that has just been
>resoldered by the plumbers, but they did not stick around to check the
>rest of the system, since they have gone the pressure is still dropping
>dramatically and is visibly going from 1.5 bar to zero witin 30-60mins.
>
>Any pointers on where to start looking, all new pipework is concealed in
>walls and joists.
>Could the boiler itself be faulty?, I have BG coming to do there annual
>service check on Wed, will they be able to diagnose the cause?
>
>Any comments/advice will be greatly appreciated
>
>Thanks
>Worried homeowner



Somewhere near the lowest point in the system you should have a drain
cock. You could drain the water into a bucket (well several buckets!)
and measure how much water is in the system after it has been filled
with the filling loop, then refill and wait 60 minutes and measure
again.

You could disconnect heating flow and return from the boiler and drain
down the system then pressure test with air. Use screwfix 10179
(http://www.screwfix.com/app/sfd/cat/pro.jsp?id=10179&ts=03963)
and some pushfit end caps: 15121
(http://www.screwfix.com/app/sfd/cat/pro.jsp?id=15121&ts=04282)
or 17170
(http://www.screwfix.com/app/sfd/cat/pro.jsp?id=17170&ts=04282)
or there's a plastic range too - you don't seem to be able to get 10mm
stop ends in cuprofit:
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=39981&ts=04356

BES is also a reliable supplier:
http://www.bes.ltd.uk/products/152.asp

All you need to do the pressure test is a car foot pump - you connect
it to the test guage and pump like hell! :-) (After putting the stop
end on the other pipe)

Some leaks can be heard as a hiss, very small leaks can be detected
with leak detection spray:
http://www.screwfix.com/app/sfd/cat/pro.jsp?id=12266&ts=03963

Don't put your head near the end cap - apparently they shoot off
sometimes (not happened to me yet!)

Mr F.

On Tue, 13 Sep 2005 10:48:35 +0100, Mr Fizzion <wankel@rotary.engine>
wrote:


>
>
>Somewhere near the lowest point in the system you should have a drain
>cock. You could drain the water into a bucket (well several buckets!)
>and measure how much water is in the system after it has been filled
>with the filling loop, then refill and wait 60 minutes and measure
>again.


Or as others have pointed out you could just see how much water it
takes to repressurise...not sure there is any point in measuring how
much water comes out!

Mr F.

Mr Fizzion wrote:

> On Tue, 13 Sep 2005 10:48:35 +0100, Mr Fizzion <wankel@rotary.engine>
> wrote:


1) Yes, no point in draining down, you never get all the water out.
Better to drain it until you get a pressure reading similar to that you
had prior to topping up. You just want an idea of the volume of water
involved. Is it a gallon or a tablespoon?

2) Pressure testing with air is inherently hazardous. If bits break or
come loose they fly around at potentially lethal velocities. Do not
"pump like hell". The system has been proved to be safe with water up
to a certain pressure, so I wouldn't exceed that. 5 -6 psi should be
adequate to hear leaks. The noise is high frequency, so young ears will
hear it better that oldies. In fact a lot of it is in the ultra-sonic
spectrum.

3) The OP isn't a plumbing expert; I would suggest he should not be
doing such testing.  The installers may claim his work has invalidated
the warranty (e.g., you've overpressurized the boiler & punctured the
heat exchanger). I'd still suggest disconnecting the new work from the
old so that the soundness of the new work can be proved.

4) A newly filled  system might need topping-up as air bubbles make
their way to the automatic air vent & are vented. Presumably, it's more
than this could account for.

5) If it's part of an old system, what happened to the open vent, cold
feed and feed & expansion tank? Have they been disconnected & removed?
If valved off, could the F&E tank be filling up & the water going out
the overflow? This would account for the lack of any wet patch.

On 13 Sep 2005 03:42:33 -0700, "Aidan"  wrote:


>2) Pressure testing with air is inherently hazardous. If bits break or
>come loose they fly around at potentially lethal velocities. Do not
>"pump like hell". The system has been proved to be safe with water up
>to a certain pressure, so I wouldn't exceed that. 5 -6 psi should be
>adequate to hear leaks. The noise is high frequency, so young ears will
>hear it better that oldies. In fact a lot of it is in the ultra-sonic
>spectrum.
>


OK, perhaps not like hell, but filling 10 radiators with air even to
1.5 bar takes quite a lot of pumps - what I meant was go at it fast
not go at it hard or else you'll be doing it all day.

I pressure tested my new system to 4 bar. Nothing came flying off. I
had one small leak in a failed Hep2o joint and one major failed
cuprofit joint (the O-ring seemed to be badly damaged) plus some small
leaks on a couple of radiator valves which were cured by adding a bit
more ptfe on the threads.

Mr F.

Mr Fizzion wrote:
 - what I meant was go at it fast

> not go at it hard or else you'll be doing it all day.
>
> I pressure tested my new system to 4 bar. Nothing came flying off.


4 bar must have taken much pumping. A lot of effort went into
compressing the air in the system. If anything HAD come flying off it
would have had a lot of energy behind it. Things flying off are quite
likely since the purpose of pressure test is not only to find leaks, as
you did, but also to cause the failure of any weak joints under
controllable conditions.

  The classic case of failure under air pressure was the Comet 1
crashes. The pressurized fuselage was failing, but they didn't know why
or where. One of the bits of wreckage recovered from the Mediterranean
crash had the imprint of a small Italian coil stamped onto it, as clear
as if it had been done in the Italian mint. The coin had obviously been
chucked around at great velocity by the explosive failure. This was at
(I think) something like 5 or 7 psi, but a large volume of air was
involved.

 When the RAE were investigating the causes, they wanted to repeatedly
pressurize/depressurize a fuselage (and cycle the loads with hydraulic
jacks). If they had used air, the bits would have been chucked all over
Farnborough when it did fail. They built a sectional steel tank around
the fuselage with the wings poking through rubber sleeves. They filled
the tank and fuselage with water & pressurized/depressurized the water
in the fuselage. When it eventually failed, it the damage was limited
to a crack at the corner of a window.

You should only pressure test with air as a last resort and with the
area evacuated. How did I learn this?

"You're not testing it with air, are you?"
"Yes, mate. We always do it like that"
"The spec says you have to test it with water. You'd better turn it
off."
"Why? I've been doing this for years and I've never had any....."
Whoompf. Thud. Hisssssssssssssssss.

Or words to that effect.

Aidan wrote:

> 
> Mr Fizzion wrote:
>  - what I meant was go at it fast
> > not go at it hard or else you'll be doing it all day.
> >
> > I pressure tested my new system to 4 bar. Nothing came flying off.
> 
> 4 bar must have taken much pumping. A lot of effort went into
> compressing the air in the system. If anything HAD come flying off it
> would have had a lot of energy behind it. Things flying off are quite
> likely since the purpose of pressure test is not only to find leaks, as
> you did, but also to cause the failure of any weak joints under
> controllable conditions.
> 
>   The classic case of failure under air pressure was the Comet 1
> crashes. The pressurized fuselage was failing, but they didn't know why
> or where. One of the bits of wreckage recovered from the Mediterranean
> crash had the imprint of a small Italian coil stamped onto it, as clear
> as if it had been done in the Italian mint. The coin had obviously been
> chucked around at great velocity by the explosive failure. This was at
> (I think) something like 5 or 7 psi, but a large volume of air was
> involved.
> 
>  When the RAE were investigating the causes, they wanted to repeatedly
> pressurize/depressurize a fuselage (and cycle the loads with hydraulic
> jacks). If they had used air, the bits would have been chucked all over
> Farnborough when it did fail. They built a sectional steel tank around
> the fuselage with the wings poking through rubber sleeves. They filled
> the tank and fuselage with water & pressurized/depressurized the water
> in the fuselage. When it eventually failed, it the damage was limited
> to a crack at the corner of a window.
> 
> You should only pressure test with air as a last resort and with the
> area evacuated. How did I learn this?
> 
> "You're not testing it with air, are you?"
> "Yes, mate. We always do it like that"
> "The spec says you have to test it with water. You'd better turn it
> off."
> "Why? I've been doing this for years and I've never had any....."
> Whoompf. Thud. Hisssssssssssssssss.
> 
> Or words to that effect.


Thanks for all the replies guys, just to give you an update, I found a
leak on one of the radiators upstairs, albeit small, the ceiling board
below the joint was visibly damp, called plumbers back and they repaired
the joint and went, pressure again dropped to zero within a couple of
hours after they had gone, called dthem back and they suspected that the
joints they had made from new piping to old system could be the only
other obvious suspect, having hacked into the wall (luckily hidden now
by kitchen units) they found a big leak with water disappearing under
the house.  Since they have fixed this, touch wood, no pressure drops in
the last week (although the system is still not in use at the mo, other
than to test the heating once for 4 hours)

Thanks once again for all the advice

Regards
Gaffar