Pressure testing a radiator

Hap_Hazzard

I've had a spare Arco radiator in my garage since I bought my house, and I've been wanting to put it in my bedroom, replacing a similarly sized but lower EDR Burnham. This summer I finally dragged it out and started stripping it. While it didn't look like it had been leaking, one of the joints started looking suspicious once I'd gotten most of the paint off. See if you can guess which one.

Hap_Hazzard

Okay, the resolution isn't that great

but if I'd zoomed in on the suspect I would have narrowed it down too much.



Anyway, it's the one furthest to the right. You can kind of see that the junction looks a little cleaner than the others. That's what made me suspicious.



So I built myself a pressure tester so I could pressurize the radiator and check for leaks. I used a blow gun, pressure gauge and a 3-way manifold, but a tee or wye would work just as well. I just used what I had lying around.

Hap_Hazzard

The blow gun does two things.

It lets you increase the pressure gradually, and it holds the pressure, allowing you to remove the air hose and watch the gauge to see if the pressure drops.



I'm not sure how much air you can safely put into these things, but I thought 20 psi was more than enough to test for leaks. I had taken the truss rods out to clean them, but I put them back in to make sure I didn't launch a section or two into the pool.



Sure enough, the pressure started to dip after about 10 minutes. After half an hour I could see it definitely wasn't my imagination, so I got my bottle of soapy water and put a few drops on each of the joints. As you can see the radiator is upside-down. I figured the leaks would probably be on the bottom.



The section I suspected turned out to have a very slow leak. I also found two other leaks that were more serious in joints that outwardly looked perfectly normal.

Hap_Hazzard

So, tomorrow I start knocking it apart.

It looks like I'm going to need three new push nipples, and depending on how they look, I might get new upper nipples for the sections I have to knock apart.

Rod

Push Nipples

Hi Hap- You probably have this address already but in case you don't, here is the source for new push nipples.

- Rod



Oneida County Boilerworks

611 Mortimer Street

Utica, NY 13502

(315) 732-7914

Hap_Hazzard

Thanks,Rod!

I knew that address was here someplace but hadn't gotten around to looking for it yet. Now I don't have to!



I also have a source for seamless steel tubing, so I might take a shot at making my own just to see what's involved. I'll post pictures for comic relief.

kcopp

Is it possible to just ....

pull them apart, clean and then reassemble w/ silicone caulk and tighten the draw rods?

Hap_Hazzard

Sure, it's possible,

But it wont accomplish anything. A high-temp epoxy might stand a better chance but would still be a temporary solution at best. These push nipples, as I understand it, are slightly tapered and pressed into slightly flared sockets. If rust gets into the joint you need to scrape down to bare metal and machine it back to round with a straight reamer, then turn the new nipples slightly oversize so you get a good, tight opposition fit.

Bio

What did

What did you use to strip the paint off? looks very clean and ready for paint, I though about using a water/lye mix to sink it in a plastic tub

Hap_Hazzard

I had all my toys out

You can see my needle scaler in the top right of the first picture. It works great for chipping areas that look mostly intact, then you can scrape away what's left with a variety of scrapers and wire brushes. I also used a "painter's helper," which is a scraper with ad couple of curved edges that work well on the tubes, and I have some narrow wire brushes that reach between the tubes.



I like to sandblast last thing before painting. A sandblasted surface holds paint really well.