How to pressure test / dry test water pipe

[tellme_why]

Hello forum,
I want to test whether some 25ish years old copper pipes (cold water, hot water and radiators) are sound - no small leaks.
The water system is open vented for both - cold/hot - and central heating.
I have all the necessary isolation valves in place.
I do not want to pressure test above current gravity pressure (two storey house) so assume about 4 metre - 0.4 bar in order not to damage the pipes or connections.

*
What test method should I use? "Dry pressure" with air hand pump connected somewhere or other test systems (some mentioned water pump) ?

Many thanks

 

[dilalio]

If you have access to the pipes and can renew them, after 25 years, why would you not?
They will deteriorate over time and now maybe the most prudent time to replace, depending on what you are doing!!!

 

[Gorgie boy]

What's the point in this rest fill it up and check.

 

[tellme_why]

the tank is about 1.5 m across so hard to say if the level really drops..

 

[muggles]

A proper pressure test method is to raise the installation to a pressure of 1.5x the normal working pressure for at least one hour, using water with as little air as possible in the pipework

If you're so nervous about the state of the pipes that you don't want to raise it above 0.4, it's time for a repipe

 

[bernardgreen]

Compressed air can store a great deal of energy which is released, sometimes creating a hazard, as it expands when escaping through a blown off fitting or burst radiator. Water, which cannot be compressed, cannot store energy. The energy stored in the pressurised system is limited to the small amount of air that is used to raise the pressure in the system and any air trapped in the system. The rate of release of that energy is slowed by the inertia of the water that has to move through the leaky or ruptured pipework / radiator.

Hence while the damage from leaked water may be significant the risk of injury from items projected by compressed air has to be considered.

 

[Agile]

Testing at just 0.4 bar is unlikely to show up anything but the biggest leaks.

For a gravity CH system the minimum to use is about 1.0 bar but most would test it at 1.5 bar which is the operating pressure of a sealed system when cold.

Many would just fill it and use it and see what happens.

Tony

 

[Stadan20]

Jesus Christ bg ... Really ?

 

[tellme_why]

.. many thanks.. I understand it's best to fill the pipes with water and pump a small quantity of compressed air, close and read pressure drops.
Now what tool to do this? -- A bicycle pump connected to the water pipe downstream the isolation (pipe connected to the water tank); there pressure is very low, connect a U-gauge, pump just 30 mbar and read U gauge to see whether pressure reduces? ..

 

[Gorgie boy]

Look mate. This is a waste of time unless you have good reason for this nonsense. Fill it up with a hose connected to the lowest point or points. So you can drain in a hurry if need be. Most leaks will be small anyway so I wouldn't be concerned. Fill up a bit at a time if you nervous. we put combos on old Yates all the time and very rarely is it a problem even rare for it to be major.

 

[gasmanstu72]

sounds like you're wasting your time, just fill it up and see if it leaks.
if it does fix it

 

[dilalio]

sounds like you're wasting your time, just fill it up and see if it leaks.
if it does fix it

That's plumbing for ya