"Edwin Pawlowski" wrote in message
t...

"Dyvim" wrote in message
There is no sight
glass on the boiler, which makes me think it is hot water, but I also
can't find any expansion tank, which makes me wonder (I've checked all
closets, attic, etc. - where could it be hidden?). The psi on the
system is around 15, which also makes me think it is hot water (too
high for residential steam). The radiators around the house are all
old cast iron 2-pipe jobs.

How can I figure this out for sure?

Sounds like water. Residential steam is less than 1# usually, should have
a
sight glass, and you'd hear some hammering in the pipes on occasion when
it
starts up.

Resi steam _should_ be under one pound. Higher pressure is actually bad in
a steam system