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.