rad caps

[dancn]

going to air test my new rad circuits soon.
I've the o-ring sealed blanking, and vent caps. After finger tight, how much should I turn these, and what's best to use to lube the o-ring.

thanks.

 

[Mbear]

What's wrong with water testing

 

[Best]

Turn them till they stop! Not joking. They will need fairly tight, & you don't want the entire plug screwing out when you try to open vent to bleed rad.
Don't need to lube the O ring really, but if you did, then silicone grease.

 

[Dannypipe]

If you are pressure testing pushfit fittings, with a compressor.....please don't over do it. It's easy to leave the compressor on until the system is at 8 Bar (as I did when I was 17) you really don't need to pressure test at high pressures. Check the system for leaks, and if no alarms are raised, then wet test the system.

A pushfit stop end coming off at 4bar will take your eye out. Please take care.

 

[Dannypipe]

Oh and as Best has said, you don't need to lube an air vent to a radiator. So don't do it.

 

[dancn]

thanks for the advice,
I'm going to test around 2 bar, I've my own little rig made with seperate regulator.
No pushfits in my system, Pex piping, brass manifolds,all compresssion fittings, all overground

 

[GQuigley67]

then personally i would just water test

 

[Ged Simpson]

The reason you don't use compressed air is that it puts a vast amount of energy into the system that will fail at the weakest point. As you have no idea where this would be, it could be catastrophic because all that energy will be released at once. With a hydraulic test, there is no stored energy due to the incompressibility of liquids, so as soon as a small amount of water escapes due to a failure, the pressure is immediately dissipated.

 

[GQuigley67]

ive only really used compressed air on commercial jobs, generally we are only allowed to do it when the site is empty incase anything blows off and 9/10 something does blow off