Pressure testing an old hot water boiler; 1963 Bryant

JUGHNE

This boiler was not started this year because of property changing hands. Electric heaters have been running in the building. It is a 47 bed nursing home....fair size building with 2 wings, that the town would like to acquire if things haven't been badly frozen.

All piping has been drained as possible, but not truly winterized.

I was thinking that for testing before spinning wheels cleaning that I would:

Disconnect the compression tank (It's in a sweet spot..see pictures)
Remove the pressure relief valve.
Fill the boiler with water up to the compression tank connection.
(There are no isolation valves and maybe no zone valves.)
Put air pressure to the entire system thru the PRV port which is located on the 2 1/2" copper supply line.
The boiler would be full of water and the air would be above it in the supply line and the return line.

Is this a viable idea? If so how much pressure would one apply to an old girl like this. The existing pressure gauge had the marker needle set at 15 PSI.

I don't want to put water pressure to the entire system as the piping is run in a sort of heated attic, under floor and other places unknown. I figure it is better to hear an air leak than wait for water to come thru a ceiling.

If it appears to hold pressure then clean the boiler, burners etc.

The nameplate says propane but it is and has been firing on NG.

Any advice greatly appreciated. There are 4 standing pilot lights on this. Any pointers on that system?

Thanks

Jamie Hall

15 psi should be ample, although to be safer you might want to run it up to 30. However... keep in mind that the air pressure will change quite a bit with temperature, and if the air you are putting in is significantly warmer than the piping -- and I'll bet it will be! -- you may see quite a significant drop early on in the test. Should stabilize after that, at least after a fashion.

If it goes to zero... well...

JUGHNE

Thanks, Jamie. You see no issue with the air over the water?

I wonder many tanks of Dry Nitrogen I could waste there to avoid the temp contraction issue?

Jamie Hall

JUGHNE said:

Thanks, Jamie. You see no issue with the air over the water?

I wonder many tanks of Dry Nitrogen I could waste there to avoid the temp contraction issue?

Air over water is no problem -- used to do it all the time to check water mains after working on them. The change with temperature is annoying.

And it would be more tanks of dry nitrogen than it's worth!