My 20yr old 3ht did that... My friend who is certified in welding silver solder it... 3 times... The last time it blew, I was pretty much irritated with taking it apart and putting it back together... My friend did it for free each time (but you buy lunch). That was a round one... I have a square 3ht that is 18yrs old and only had a pin hole that he also fixed... I believe the round one kept blowing because the fire was directly on the repaired part... Hopefully that works for you...