Baseray keeps cracking

Dan C.

I have a customer who has two zones of cast iron baseboard. For some reason at least one piece cracks every year. I thought it was freezing but this time when it happened it wasn't below freezing and the piece that cracked is on an inside wall. I can't figure out why this is happening. It's not corrosion. It just cracks suddenly and floods the whole house. Has anyone dealt with this before?

Tinman

I've never heard of anything to that extreme before. It's actually cracking? Not a problem at the push nipples where two pieces are joined?

Dan C.

No. Not the joints. It's always on the cast iron itself. Sometimes on the front and sometimes on the top behind it.

Tinman

Are the rough-in holes drilled a 1/2" or so larger than the pipe itself allowing some movement as the baseboard heats up? What SWT is the boiler running at? No room for expansion and very high water temperature might do it? Is it an older or newer system?

Jamie Hall

As Stephen says, the only thing I can think of is that the units are restrained in some way. Cast iron is brittle, and will fatigue if subjected to alternating stress -- but this does sound rather extreme.

Dan C.

1/2" copper feeding baseboard with square holes in the hardwood and subfloor with clearance around it. High Limit is set at 180 but it gets to 190. Old system. House was built in 1950's. Not sure when baseboard was installed but sometimes the sections don't line up when I go to replace it so it is older than the most recent Baseray.

Tinman

I've purposely cracked cast iron and accidentally cracked cast iron but other than what I've shared based on what you've shared...I don't know?

Tinman

Thinking outside the box - house settling?

Dan C.

I attached some pictures. I guess the house could be settling. They want to rip it all out and replace it with fin tube. I would hate to do that but I can't think of what could be causing it.

Jamie Hall

That crack is just plain weird. I can't think of any logical stress application that would stress it in that particular way -- the only thing I can think of there is a bending stress perpendicular to the crack, and I can't see how you would do that.

However, a question: is the failure always in one of the original sections, or does it happen in one of the newer sections? Because one possibility is embrittlement in the old cast iron... or casting flaws.

EBEBRATT-Ed

Can't think of anything. Check the water PH ?? Any buried piping leaking?? All I got are longshots.

kcopp

sure looks like freezing to me. It may have froze last year , had a micro crack and when hit w a hot slug of water this year it let loose.

Dan C.

It is always the old stuff. The only new is the 4 sections that I have put in throughout the house which are all either 1' or 2' sections all in different rooms.

Haven't check PH. No underground piping or leaks. Doesn't seem like corrosion. Each time it is a crack. One time they actually heard it crack and then it started spraying.

I originally thought they were freezing and cracking but this one is on an inside wall. It definitely didn't freeze.

kcopp

You could replace it w/ a freestanding CI radiator. Still would have the feel of even heat vs. the fin tube. Obviously would need to do some drywall.