mike wrote:

has anyone gone through the process of converting a steam system to
hot water by using the old steam radiators and piping? i have been
told i can do this since i have a two pipe system with the hot water
type of radiators. but I can't help but wonder whether my the size of
my steam pipes is too large. i think my main is 3". also i wonder if
the system will leak with hot water. any thoughts. thanks.

Why would you convert it? Steam heating works well and new steam boilers
are readily available. Not like it's something obsolete. You can fuel a
steam boiler with gas or oil, just like a hot water boiler. Why try to
partially convert a system to make it less efficient?