What pressure to test new pipework?

[mark_j_k]

Hello everyone, just a quick question about pressure testing pipework.

I have replaced all our radiators and pipework prior to having our boiler changed. Currently they are not connected to any 'live' part of the heating system.
I wish to test the system for leaks before I get a plumber to install a new boiler but I wish to know what pressure I should charge the new pipework and radiators to.

I have just bought an air pressure test gauge with the usual Schrader Valve on it that I will attach to on of the open ends of the pipework.

Is a foot-pump powerful enough to pressurize the system? I don't want to spend hours pumping air in that could be escaping somewhere without me knowing! I have a small compressor with a tyre inflating atachment that I could use - could this be used?


Thankyou,
Mark.

 

[gas4you]

I always use a compressor.

I have a medium size one for testing ch systems. I always test to 3.5Bar for about 1 hour.

I use 3.5Bar so that I have tested the system higher than the 3 Bar prv will blow at.

 

[megawatt]

Definitely can't use a footpump unless you have a lot of time, patience and leg muscles like Popeye

 

[doitall]

Air testing should never be carried out unless all the safety measure are put in place prior to doing the test, and in any case you would only need a maximum of 42mb and a standard manometer.

A fitting blowing off at 3.5bar as above would pass right through a human body.

 

[holty]

usual recommended pressures 1&1/2 times the working pressure. if any pushfits are used decrease the pressure after 30 mins about a third to test the grab rings.

 

[oilman]

To amplify dia's point, pneumatic testing is DANGEROUS!! Pressure testing on unknown systems should be hydraulic, that way the stored energy is small, but you should take expansion vessels off IMO to ensure there is minimum energy storage.

 

[Softus]

I have just bought an air pressure test gauge with the usual Schrader Valve on it that I will attach to on of the open ends of the pipework.

Take it back, and write out 100 times:

"I must not pressure test a heating system using air."

Is a foot-pump powerful enough to pressurize the system?

As doitall has already pointed out, that would be an unacceptable risky thing to do.

 

[doitall]

usual recommended pressures 1&1/2 times the working pressure. if any pushfits are used decrease the pressure after 30 mins about a third to test the grab rings.

That is an hydraulic test holti and not pneumatic which is roughly equal to 10 x that of water.

3 bar air = 30 bar water, I think and boys will will soon tell me if I'm wrong

 

[megawatt]

Not a dangerous thing to do if the pressure is kept low yet still sufficient for a first stage (and easy) leak check.

A few psi isn't going to cause any problems IMO.

MW

 

[doitall]

Not a dangerous thing to do if the pressure is kept low yet still sufficient for a first stage (and easy) leak check.

A few psi isn't going to cause any problems IMO.

MW

That what I said 42mb and a manometer is plenty and you can blow that with the mouth.

 

[giblets]

Air pressure can be maintained by un-soldered but fluxed joints. Water testing will find such problems.

 

[Softus]

Air pressure can be maintained by un-soldered but fluxed joints. Water testing will find such problems.

How does that work? Are you saying that, at the same pressure as a wet test, a dry test will not exert the same force on a loose fitting because of the flux?
_______________

Edit: corrected typo.

 

[megawatt]

Air pressure can be maintained by un-soldered but fluxed joints.

Not in my experience.

 

[sambotc]

flux is water soluble though, so may have a small effect depending on the leak, wouldnt agree with it based on 'unsoldered but fluxed' leaks though.

Sam

 

[Durgo]

That powerflow flux jams the fittings on the pipes so badly I could almost beleive it...and Ive discovered unsoldered endfeed fittings that didn't leak on a vented c/h system before but 3.5 bar would expose ANY lack of solder i'm betting...but I'm not a plumber so what do I know lol