Rad leak test

OhioRuss

I got ahold of some old cast iron radiators I would like to use in our home. How do I test them for leaks? Should I test before or after I sand blast them? These are for hot water. Thanks

Mark Eatherton

Both...

And it should be a low pressure test, like not more than 20 PSI.



If the radiators is bad, why pay to sand blast and powder coat or paint?



These puppies are heavy and hard to handle, so when they come back from the treatment, test them again.



Hydrostatic tests will "show" the leak better than compressed air.



ME

icesailor

Testing Radiators:

For the sake of discussion, I think that testing with air is a better choice because you can use leak detector on all the joints. And look for bubbles. I've seen many old radiators "weep" with water but the "weep" evaporates before you can see it.

I've tested gas piping to the required 5# maximum and had the pressure drop slightly in 24 hours so I knew that there was a leak. I soaped everything and couldn't find any leaks. I raised the pressure to 100# and the pressure dropped at a higher rate. I found the leak quickly with liquid leak detector. After fixing it, I dropped the pressure to 5# for the inspection.

In no way would I suggest testing a radiator to 100#, but I use air for testing over anything else.

Air is my drug of choice for any test I can do. With my high pitch hearing sensitivity, I can hear the cat breathing on the couch. A leak in a wall is a piece of cake.

Whatever works for you. I far prefer cleaning up after an air leak than a water leak.

Steamhead

We test them with water

if they hold 30 PSI for 15 minutes, they're OK.



The problem with air testing is that compressed air has a lot of energy. If you fill a rad with air and something lets go, you will get an explosion and someone could get hurt. Water cannot be compressed so it won't do this.

Steamhead

I hate double posts...........

Dan, you can delete this one if you wish.

icesailor

Air testing:

Steam,

I never test with more than 10# if I am testing anything like a radiator. I find that I don't need to. If it leaks at 100#, it will leak at 5#. Take a tire inner tube. You can have a slow leak that takes weeks to go down. You can put it in a water tank and wait a long time for a bubble. For some reason, spraying a soapy solution on the tube will show the leak quicker than the water tank. 

Your point about compressed air energy is well taken.

Try some soap on a radiator with very low pressure air. That's what I do.

tim smith

testing radiators

I am with Mark and Steamhead, water test, we test at least at 30 psi before and after. We usually set in dry area and go over joints and sections with fine tooth comb looking for seepers. This has always worked for us.  I have had problems in last year with leakers after powder coat. I talked to powder coater and he was bakiing off a little warmer and little longer and was killing the gaskets it seemed. I told him to stop, ruined some beautiful rococco rads.