Posted by Harold Kestenholz - Hydronic Network on August 20, 2000 at 11:28:35:
In Reply to: Weil-McClain MGB-5 leaking at side fitting posted by Mark Wollman on August 20, 2000 at 08:27:38:
The ordinary way to remove the remaining pipe from threads is to carefully cut the pipe the long way from the inside until just reaching the threads in the boiler. Three such cuts (or more) make smaller pieces that can be driven toward the center of the hole by a chisel on the outside of the pipe. Circular motions along the threads with an awl and steel brush in your hand (without damaging the threads) will clear the threads of debris. Chasing the threads lightly with a correct-sized female pipe threader can do it too, but this is chancey as you might snap some of the old threads by too much force from the leverage of the tool. There are square nipple-remover tools that will grab the inside of the pipe stub to turn it out without cutting, but you might have to do the pipe-cutting trick anyway because of age oxidation welding of the old pipe threads to the boiler casting.