About 40 years ago my Dad pressure tested a DIY plumbing installation using a car tyre valve (soldered somehow into a 1/2 inch BSP compression fitting), a foot pump and a car engine compression gauge. After filling the system with compressed air he left it overnight and checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic (JG Speedfit) central heating system prior to filling (the gas fitter is coming to fit the boiler on Tuesday)? I can seal off the open ends.

In article ,
Moz writes:

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

Yes. You can buy an adaptor with a 15mm pushfit, a tyre valve, and
a pressure guage, e.g.
http://www.screwfix.com/app/sfd/cat/...10179&ts=53191

It's much easier to dry test in sections than it will be to do the
whole system at once, but if you've already constructed it all, I
wouldn't bother breaking it apart now. It takes a lot of effort to
pump up even a couple of radiators to 2 bar, and I wouldn't dare
go that high with a whole system, as the energy stored in it will
be massive -- if any part does break apart it will fly apart
explosively (release the pressure gradually when you're done, from
something like a bleed valve, not by pulling apart a fitting;-).
The relevant British Standard recommends evacuation of the
building when pressure testing pipework with air.

I would suggest getting a can of gas leak detector spray too.
You spray this on all the joints and it will give a much faster
and more accurate indication of any leaks than will watching for
a drop on the pressure guage (grows a large gobit of cuckoo spit
at each leak site). I can't see this in screwfix's online
catalogue, but any plumbers merchant will have it. I used LD90
http://www.actioncan.com/ld90.htm but there are other makes.

--
Andrew Gabriel

In article ,
Moz wrote:
About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

If you get a 'high speed' valve, these are held in place by a nut with
rubber washers either side rather than the pull through rubber type. Drill
a stop end and fit it to that. A place selling aftermarket alloy wheels
should have them. When I installed my heating I used this idea with two
pick up points for an in and gauge. Once happy there were no leaks
replaced them with plain stop ends.

--
*Bills travel through the mail at twice the speed of cheques *

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 02 Dec 2006 06:23:00 +0000, Moz wrote:


About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

You can pump it up to a fraction of a bar with a bicycle pump and a lot of
hard work to check for obvius leaks. I usually connect up to the mains
water supply since that is about 3-4 bar around here which is a good
margin above what a CH system will be running at in practice. After
initial pressuring up and checking for obvious leaks you need to bleed the
rads (or at least let some water into them) to catch leaks at the rad
valves, otherwise slight leaks won't show up until the air has
escaped and you may end up with a puddle on the floor several hours later
when the water finally gets through.

John Stumbles wrote:
On Sat, 02 Dec 2006 06:23:00 +0000, Moz wrote:


About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

You can pump it up to a fraction of a bar with a bicycle pump and a lot of
hard work to check for obvius leaks. I usually connect up to the mains
water supply since that is about 3-4 bar around here which is a good
margin above what a CH system will be running at in practice. After

Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.

Ian Stirling wrote:
Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.

Is it just about speed? Or is it likely that a system could be
watertight - ie perfectly serviceable in practice - but not actually
100% airtight?

(Interested because I have to do some similar testing after Xmas sometime.)

David

Lobster wrote:
Ian Stirling wrote:
Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.

Is it just about speed? Or is it likely that a system could be
watertight - ie perfectly serviceable in practice - but not actually
100% airtight?

Umm...
It depends.

For example, you'll likely never notice a leak that leaks 500ml/month,
but it'll cause a sealed central heating system to lose its pressure in
a few months.

If it's significantly below this - say 50ml/month, then if the boiler is
being serviced annually, you'll probably never know.

But, it may well leak very detectably with air.

In article ,
Lobster writes:
Ian Stirling wrote:
Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.

Is it just about speed? Or is it likely that a system could be
watertight - ie perfectly serviceable in practice - but not actually
100% airtight?

If you get it airtight, it will certainly be watertight.

It should be airtight in any case, otherwise air leaks
in (even when the water pressure is much higher than air
pressure) and causes bubbles which can make a noise, and
use up the inhibitor faster, possibly resulting in
corrosion starting sooner than you's expect.

--
Andrew Gabriel

"Moz" wrote in message
...

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

No. Never test with compressed air. If a fitting fails it can shoot off like
a rocket and seriously hurt.

"Andrew Gabriel" wrote in message
...
In article ,
Moz writes:

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

Yes. You can buy an adaptor with a 15mm pushfit, a tyre valve, and
a pressure guage, e.g.
http://www.screwfix.com/app/sfd/cat/...10179&ts=53191

It's much easier to dry test in sections than it will be to do the
whole system at once, but if you've already constructed it all, I
wouldn't bother breaking it apart now. It takes a lot of effort to
pump up even a couple of radiators to 2 bar, and I wouldn't dare
go that high with a whole system, as the energy stored in it will
be massive -- if any part does break apart it will fly apart
explosively (release the pressure gradually when you're done, from
something like a bleed valve, not by pulling apart a fitting;-).
The relevant British Standard recommends evacuation of the
building when pressure testing pipework with air.

I would suggest getting a can of gas leak detector spray too.
You spray this on all the joints and it will give a much faster
and more accurate indication of any leaks than will watching for
a drop on the pressure guage

High pressure escapes will not blow bubbles.

Doctor Drivel wrote:

"Moz" wrote in message
...

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

No. Never test with compressed air. If a fitting fails it can shoot off like
a rocket and seriously hurt.

Yes, it can - some care is needed.

For maybe a bar of pressure, you've got 4Kg of force on a 22mm fitting.
Over 3cm, this'll accellerate a 100g fitting to maybe 20m/s, if it comes
completely loose, and has no attachment to the pipe at all.

Don't stand anywhere a fitting could fly.

Andrew Gabriel wrote:
In article ,
Lobster writes:
Ian Stirling wrote:
Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.
Is it just about speed? Or is it likely that a system could be
watertight - ie perfectly serviceable in practice - but not actually
100% airtight?

It should be airtight in any case, otherwise air leaks
in (even when the water pressure is much higher than air
pressure)

OK I'll bite: how does that work?!
David

In article ,
Lobster writes:
Andrew Gabriel wrote:

It should be airtight in any case, otherwise air leaks
in (even when the water pressure is much higher than air
pressure)

OK I'll bite: how does that work?!

http://groups.google.com/group/uk.d-...c?dmode=source

--
Andrew Gabriel

"Ian Stirling" wrote in message
...
Doctor Drivel wrote:

"Moz" wrote in message
...

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

No. Never test with compressed air. If a fitting fails it can shoot off
like
a rocket and seriously hurt.

Yes, it can - some care is needed.

For maybe a bar of pressure, you've got 4Kg of force on a 22mm fitting.
Over 3cm, this'll accellerate a 100g fitting to maybe 20m/s, if it comes
completely loose, and has no attachment to the pipe at all.

Don't stand anywhere a fitting could fly.

That is why the professionals use water.

On Sat, 02 Dec 2006 13:27:25 +0000, Doctor Drivel wrote:

"Andrew Gabriel" wrote in message
...
In article ,
Moz writes:

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

Yes. You can buy an adaptor with a 15mm pushfit, a tyre valve, and
a pressure guage, e.g.
http://www.screwfix.com/app/sfd/cat/...10179&ts=53191

It's much easier to dry test in sections than it will be to do the
whole system at once, but if you've already constructed it all, I
wouldn't bother breaking it apart now. It takes a lot of effort to
pump up even a couple of radiators to 2 bar, and I wouldn't dare
go that high with a whole system, as the energy stored in it will
be massive -- if any part does break apart it will fly apart
explosively (release the pressure gradually when you're done, from
something like a bleed valve, not by pulling apart a fitting;-).
The relevant British Standard recommends evacuation of the
building when pressure testing pipework with air.

I would suggest getting a can of gas leak detector spray too.
You spray this on all the joints and it will give a much faster
and more accurate indication of any leaks than will watching for
a drop on the pressure guage

High pressure escapes will not blow bubbles.

But they can easily be heard, instead.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

On Sat, 02 Dec 2006 15:35:32 +0000, Ian Stirling wrote:

Doctor Drivel wrote:

"Moz" wrote in message
...

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

No. Never test with compressed air. If a fitting fails it can shoot off like
a rocket and seriously hurt.

Yes, it can - some care is needed.

For maybe a bar of pressure, you've got 4Kg of force on a 22mm fitting.
Over 3cm, this'll accellerate a 100g fitting to maybe 20m/s, if it comes
completely loose, and has no attachment to the pipe at all.

Don't stand anywhere a fitting could fly.

Agreed. My own rule is that I pump with air to about 1/2 bar. If you can
get that far then nothing has been forgotten. I'll then go up a little
further say to 0.7 bar and leave it a while. If it holds pressure for 15
minutes then the air is released slowly (bleed valves) and the water is
used. The only other way I can then have a puddle is when there is a joint
that's not fully taken but the flux is holding it sound when cold.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards

Ed Sirett wrote:
On Sat, 02 Dec 2006 15:35:32 +0000, Ian Stirling wrote:

Doctor Drivel wrote:
"Moz" wrote in message
...
About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.
No. Never test with compressed air. If a fitting fails it can shoot off like
a rocket and seriously hurt.
Yes, it can - some care is needed.

For maybe a bar of pressure, you've got 4Kg of force on a 22mm fitting.
Over 3cm, this'll accellerate a 100g fitting to maybe 20m/s, if it comes
completely loose, and has no attachment to the pipe at all.

Don't stand anywhere a fitting could fly.

Agreed. My own rule is that I pump with air to about 1/2 bar. If you can
get that far then nothing has been forgotten. I'll then go up a little
further say to 0.7 bar and leave it a while. If it holds pressure for 15
minutes then the air is released slowly (bleed valves) and the water is
used. The only other way I can then have a puddle is when there is a joint
that's not fully taken but the flux is holding it sound when cold.


I tested my UFH using a water pump and pressure gauge. Took it to 10 bar
and left it at 6 bar overnight. Kept it at that while the screed went
down. It cost me a fiver to hire the pump and gauge for a few days.

On Dec 2, 11:59 am, Ian Stirling wrote:
Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.

True, but since it's compressible, the leak of a small volume of air
will cause a small reduction in pressure. For the same reason, you'll
be pumping away forever at the foot pump to get the system up to test
pressure.

Water is incompressible, so the leak of a small volume of water will
cause a large pressure loss, usually all of the pressure very quickly.
If you've used a pukka water test pump, a few strokes of the pump will
usually get a system up to pressure, if you've got all the air out. If
you're expecting it to pump up like a car tyre, it is easy to
over-pressurize and damage the system.

The air pressure also varies a lot with ambient temperature changes.
Air just isn't a very good medium for pressure testing, besides the
safety aspects.

The Water Regulations specify a hydraulic test at 1.5 times the
maximum working pressure for water supply pipes (OP has a CH system, so
the Regs don't apply). For plastic pipes, two special test procedures
are specified, because it expands gradually & slightly under pressure,
causing a reduction in pressure. One procedure requires the system to
be pumped up to the test pressure and the pressure is maintained by
further pumping (as the pipe expands) for 30 minutes The permissible
pressure drop is then nmt 0.6 bar for the next 30 minutes, followed by
nmt 0.2 bar over the next 2 hours and no visible leakage.

Rehau (and other manufacturers, I'm sure) specify a similar test
procedure for their plastic plumbing pipe.

In article ews.net,
Doctor Drivel wrote:

"Moz" wrote in message
...

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

No. Never test with compressed air. If a fitting fails it can shoot off
like a rocket and seriously hurt.

Which is why you should have a gauge attached while you pressurise the
system. However, most won't have many fittings hanging off the end of a
pipe unsecured in some other way. Apart from in one of your
'installations' obviously.

--
*Very funny Scotty, now beam down my clothes.

Dave Plowman London SW
To e-mail, change noise into sound.

Aidan wrote:


On Dec 2, 11:59 am, Ian Stirling wrote:
Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.

True, but since it's compressible, the leak of a small volume of air
will cause a small reduction in pressure. For the same reason, you'll
be pumping away forever at the foot pump to get the system up to test
pressure.

Water is incompressible, so the leak of a small volume of water will
cause a large pressure loss, usually all of the pressure very quickly.

Oops, I completely forgot about that aspect.
If there is no pressure vessel, and no trapped air, then the only
pressure held in the system is by virtue of expanding metal, and
compressed water. So quite low volume to leak.

"Ed Sirett" wrote in message
...
On Sat, 02 Dec 2006 13:27:25 +0000, Doctor Drivel wrote:

"Andrew Gabriel" wrote in message
...
In article ,
Moz writes:

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

Yes. You can buy an adaptor with a 15mm pushfit, a tyre valve, and
a pressure guage, e.g.
http://www.screwfix.com/app/sfd/cat/...10179&ts=53191

It's much easier to dry test in sections than it will be to do the
whole system at once, but if you've already constructed it all, I
wouldn't bother breaking it apart now. It takes a lot of effort to
pump up even a couple of radiators to 2 bar, and I wouldn't dare
go that high with a whole system, as the energy stored in it will
be massive -- if any part does break apart it will fly apart
explosively (release the pressure gradually when you're done, from
something like a bleed valve, not by pulling apart a fitting;-).
The relevant British Standard recommends evacuation of the
building when pressure testing pipework with air.

I would suggest getting a can of gas leak detector spray too.
You spray this on all the joints and it will give a much faster
and more accurate indication of any leaks than will watching for
a drop on the pressure guage

High pressure escapes will not blow bubbles.

But they can easily be heard, instead.

Depends on the pressure and the size of the hole.

"Dave Plowman (News)" wrote in message
...
In article ews.net,
Doctor Drivel wrote:

"Moz" wrote in message
...

About 40 years ago my Dad pressure tested a DIY plumbing installation
using a car tyre valve (soldered somehow into a 1/2 inch BSP
compression fitting), a foot pump and a car engine compression gauge.
After filling the system with compressed air he left it overnight and
checked for pressure drop.
Does anyone know if this would be an appropriate way to test a plastic
(JG Speedfit) central heating system prior to filling (the gas fitter
is coming to fit the boiler on Tuesday)? I can seal off the open ends.

No. Never test with compressed air. If a fitting fails it can shoot off
like a rocket and seriously hurt.

Which

Please you please eff off as you a total dangerous idiot.

In article ,
Ian Stirling writes:
Aidan wrote:


On Dec 2, 11:59 am, Ian Stirling wrote:
Air goes through holes much, much easier than water, and will escape
hundreds of times faster than if filled by water.

True, but since it's compressible, the leak of a small volume of air
will cause a small reduction in pressure. For the same reason, you'll
be pumping away forever at the foot pump to get the system up to test
pressure.

Water is incompressible, so the leak of a small volume of water will
cause a large pressure loss, usually all of the pressure very quickly.

Oops, I completely forgot about that aspect.
If there is no pressure vessel, and no trapped air, then the only
pressure held in the system is by virtue of expanding metal, and
compressed water. So quite low volume to leak.

Also, one of the reasons to keep the system dry until you are
sure of no leaks, i.e. trying to resolder a wet pipe, doesn't
apply if there are no soldered joints.

However, air leaks are easier and quicker to find than water
leaks.

--
Andrew Gabriel