radiator piping

mike chacon

I have an old hydronic system with iron radiators that have piping entering radiator on bottom left side and exiting on top right side of radiator.  I am replacing all piping including old boiler to pex piping from manifold system.  I would like to reuse old cast iron radiatiors. Should I re-pipe to old radiators  with pex pipe to bottom of old radiator (supply and return) or should I go into bottom on one side and exit on top on other side of radiator as previously done.  This old system has a pump on it.  Was it previously a conversion from a steam system before, based on existing piping to radiator (high and low)?  Can I reuse old radiators?     MC

Al Letellier_21

old radiators

Most likely you had an old two pipe steam system where the steam entered at the top and existed out the bottom. I have seen a few gravity hot water systems set up that way as well. I would try to keep the set up the same. Entering and leaving at the same level will tend to flow water right across the bottom of the rad and diminish the output....maybe not a big issue as most are way oversized anyway, but I like the look and it works better to leave it as is.