Pressure testing; how much PSI before install on my used NY ' R WC-120

Hello Everyone,

I recently posted about making my New Yorker WC - 102 boiler more efficient; digging around this GREAT website I found that suspending chains in the tubes may help....

I have done a lotta work on this boiler; welded new studs on the water jacket inspection plate, grinding it down, painting, etc.
(I also got it into my cellar alone with a 1 ton chainfall; whatta job that was!)( I needed to get it outta the rain after painting and couldn't get anyone short notice)

Now I need to pressure test it before install.

I will first charge it with air and soap the fittings, then fill it with water and pressure test.

The big question is how much PSI?

My New Yorker Boiler sez tanks in advance.....