Re: Air pressured testing of pipework

Paul Roman wrote:

sort of loss you are measuring should be called a win. In fact that sort of drop in an hour would probably be OK. Not least there will be an initial drop as the pressurized air cools down are it has been put in. It is possible that the rad valve glands are letting a bit by.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
<SNIP>

BTW What did you do about the auto bypass requirement on your Keston? (See 'Central heating bypass circuit' thread.)
Thanks
Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Paul Roman wrote:

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I tested the heating circuits I did this way too. Some got left pressurised for weeks, but didn't lose any pressure. (Mostly, I tested at 2 bar because pumping 3 or so radiators up higher than that with a bicycle pump would kill me. As Ed said, air is much less viscous than water, and will leak out at very many times the speed water would.) What does happen though is the pressure changes slightly as the temperature of the pipework changes. If you want to check for this, make sure the temperature isn't changing, or you leave it until the temperature has got back to same value. Don't forget to check all the radiator blanking plugs and bleeding niples with leak detector too. Also, don't assume there are no leaks inside the Keston -- the drain cock was leaking in mine where it screwed into a cast elbow, which showed up as an air pressure drop when I was testing -- fortunately easily fixed.
BTW, you get the same effect doing a soundness test on gas piping if it's changing temperature (e.g. if there a length exposed outside and the sun goes in), only it's much more noticable.
--
Andrew Gabriel

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Andrew Gabriel wrote:

The testing of gas pipes is done at two magnitudes less pressure. For the reasons you state there is a one minute settling time before the start of the test to reduce the thermal effects.
With an electronic manometer the last digit is 0.00001 bar if you as much as put a hand on a gas pipe the digits will start to move.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.