"thehip" wrote in message
news:aI7Ch.2560$EU.1390@trnddc07...
Hello I have gas fired steam heat with the old cast iron radiators.
My question is that recently over the past 2 years when the heat is turned
on
I hear the cast iron pipes banging or clanking in the first few minutes
and then it stops.
All the radiators get very hot which leads me to believe they are not
clogged.
All of them have new vent valves. Only some of the exposed pipes in the
basement are
insulated. This banging has become more frequent as the years pass.
What could cause this? Is there air in the system or does that problem
only pertain to
hot water baseboard. Should I insulate the pipes? I also frequently drain
water from
the low water cut off valve and refill it to the proper level. Should the
return pipes
also be insulated? Thanks for any info.

The banging you hear is water hammer from condensation in the system. Very
normal for a steam heater. Some of us think of it as music rather than just
noise.

Insulating the pipe won't make any difference. The exposed pipe are giving
off heat, just like the radiators are. It is not lost heat because it is
heating the house. If the pipes pass through areas that you do not want
heated, they should be insulated there. Check the water level in the system
and be sure thee is room for the condensate to all return.

You may want to get a book about steam heating
http://www.heatinghelp.com/shopcart/...category=2-109

It should give you some tips to lessen the noise, as well as other steam
tips.