Pressure test with air?

scatgo · 12:47AM

Almost done with installing a new boiler. I was thinking it might be a good idea to pressure test the whole system with air before I fill it with water. In the process of trying to figure out how to do that. Any suggestions would be appreciated.

Jamie Hall · 1:27AM

Use water.

Seriously. If you use air, at any significant pressure, and something lets go, you are going to have pieces flying all over, and I don't like shrapnel. Scares me. If you use water, all that will happen is you will get wet. Second reason: air pressure is very temperature sensitive, A rising temperature will hide a small leak. Dropping temperature will look like one.

Use water.

hot_rod · 2:01AM

pretty much all the components with the exception of the boiler can handle 40-60 psi

Hydronic work done during freezing weather is often air tested first

Tiny air leaks can be tricky to find, leak detection bubble solutions work well

scatgo · 3:40AM

https://forum.heatinghelp.com/discussion/comment/1903947#Comment_1903947

I plan on useing a bicycle pump to bring the pressure up to the manufactures recommended max psi of 55. just not sure how to go about it. It would be a pain in the azz if I had to drain down the whole system if one threaded connection leaks.

hot_rod · 3:54AM

you need to cap off any auto air vents on the system, the purger at the boiler for one.

A test block like this may be the simplest, unscrew the expansion tank and install it there. If you can’t isolate the boiler get a 30 psi version of this and stay below that 30 psi relief setting.

109A_5 · 4:19AM

" I plan on useing a bicycle pump to bring the pressure up to the manufactures recommended max psi of 55 "

Wow, ever fill up a flat (empty) truck tire with a bicycle pump ? You may be there a while, pumping and pumping and pumping…….. I'd at least fill the boiler with water. The more water in the system the less air needed to build the pressure up.

As @Jamie Hall stated Hydrostatic testing is safer.

scatgo · 4:54AM

OK now you got me thinking. How about this. Take a cap and drill it. Put a valve stem in it. You can pick one up at any auto parts store. Place the cap on a nipple that will fit the pressure relief valve. Lift the lever on top of the relief valve and add some air. The aqua balance furnace has a pressure gauge on it. And i think I can just tighten the cap on the air separator to keep the air in the system. Bring it up to pressure and see if the pressure gauge on the furane drops after a few hours. Maybe let it be over night. No rush at the moment. And the expansion hasn't been installed yet so a cap on the nipple coming from the air separator.

mattmia2 · 5:02AM

you can get a test gauge that will screw on to hose thread that you can screw on to a boiler drain. you can also drill a hole in a plug and solder a schrader in to it, possibly one that you salvaged from an old innertube and stripped the rubber off of.

109A_5 · 6:19AM

" Take a cap and drill it. Put a valve stem in it. "

Interesting idea. 29/64" or 0.453" or 11.5 mm.

There is this style too, more sturdy used for LT tires / wheels

Also schrader valve to 1/8" NPT, at NAPA Autoparts stores and maybe also Harbor Freight.

1/8" NPT

Pressure test with air?

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