Cracked cast iron rad

rjean

I have had three radiators crack all at separate times all while the heat was on and radiators were hot. What causes this

Jamie Hall

Any number of reasons why a piece of cast iron would crack — eventually. Restraint on expansion or contraction, over pressure, impact… all usually starting from minor irregularities in the casting…

To have three on the same system crack over a short period of time makes one want to look for a common factor, though. Could be as simple as the way they were shipped. Need to know a lot more.

ethicalpaul

is it definitely a crack or is it a rusted hole?

Waher

pictures?

rjean

rjean

I believe it’s my pressure building up how do I stop it from building up

jesmed1

What is your boiler pressure relief valve setting, and have you ever exercised it (ie opened the valve to make sure it's not frozen in place)?

mattmia2

Having previously frozen or severe corrosion seems like the only way. For baseboard like that freezing seems much more likely.

jesmed1

I was going to say, looks like a crack you would expect from having it freeze full of water.

pecmsg

there is no way that boiler built up enough pressure to break that radiator!
I agree it looks like a previous frozen weekened and finally let go

ScottSecor

Is this a hot water or steam system?

It is very rare for cast ion heat emitters to crack. Cast iron baseboard may be more prone, but we rarely see them crack under normal circumstances. If water froze inside it could certainly cause a crack.