Overfill Pinhole Leaks

Garrett209

We have a single-pipe steam system probably installed 80 years ago when our house was built. The current furnace and boiler went in in 2005. In 2011 we were away from home and the basement flooded, causing the boiler auto-fill valve to fail in hard-on position for a while. Steam system filled with water, which dripped back down thru house. Hex plugs at upper end of terminating radiator sections (opposite end of radiator from supply pipe & shutoff valve) have circular caps on their ends like little pancakes (caps about 1" diameter and 3/16" thick). Caps have small triangular holes (about 1/8" equilateral) that now seem to leak some steam.



What can anyone tell me about the triangular holes in the caps, and the caps themselves for that matter? Are the holes intentional relief holes? Did something blow out that needs to be replaced, or plugged up somehow, say by JB Weld or the like?



Thanks,

Garrett

MTC

Posting some pictures

would help. But it sounds like you have radiators with built in air vents. The one's I'm familiar with are the "In-Air-Rid" ones, if they're those, that would be stamped in the cap and the dot on the "i" in Air would be the vent hole. These are usually plugged up over time with paint and new external vents are added. The pressure from all the water may have unplugged these holes.



I'm not sure if there's any way to get those functioning again if they're screwed up, but I'm guessing not. I always thought they'd be a nice way to do a 1 pipe system, though less adjustable, etc. I imagine in your situation, the best thing would be to plug them up, JB Weld might work, you're only holding back about a pound of pressure, so doesn't need to be anything too crazy.



But I'd post some pics to be sure that this is what's going on...