Hi,
I have an older home with a natural gas boiler in the basement that runs these massive galvanized pipes through the basement to the baseboards for heat. I am assuming some time ago the old metal radiators were replaced with baseboard units. I can see that the baseboards have copper but the main pipes are galvanized. Anyways, I want to start replacing the large galvanized pipe with smaller copper pipe to help bring the pipe closer to the basement ceiling. I am about to remodel the basement. The current galvanized pipe that run in the basement is huge; probably 2 and 3 inch. I am hoping since the large radiators are gone and the baseboards have 1/2 pipe, I can use smaller copper to replace these, like 1 1/2 or 1 1/4? What is your recommendation?

 

It can be done of course. You would need to know how many GPM that the main pipes must carry and size them appropriately. You could also use properly sized PEX (plastic) tubing.

There's a bit of 'engineering' that would need to go into doing it right... so if you design it, make sure to do all your homework!

 

That pipe, if it's 2-3" is rather enormous unless the system was originally set up for gravity flow. Steel pipe size goes by i.d., not o.d. I have a relatively large house, and the largest pipe is 1-1/2" (for the main). I assume that your large piping is serving perhaps the whole house, not just baseboard units in the basement? If so, you may not want to reduce the i.d.

Don't underestimate the effort required to loosen old pipe connections, particularly large ones. You'll want a pair of 24" pipe wrenches. Since you are intending to replace the pipe, it might be simpler to cut it out with a Sawzall?

 

Hi, so I did find out that the reason the galvanized pipe is up to 3 inch in the basement was because it used to be a gravity fed system several decades ago. The old owners did not want to pay to replace the galvanized pipe so the kept it. So I have a natural gas boiler using 1 1/4 copper. All of the baseboards are 1/2 copper. In between is over sized galvanized pipe, except the pipe going to the second floor, they are 3/4 galvanized. So I want to replace the oversized pipe that runs on the basement ceiling, with 1 inch pex. That would mean the boiler would have 1 1/4 copper, then 1 inch pex running to the 1/2 inch base boards on the first floor. I cant replace the 3/4 inch galvanized running to the second floor 1/2 inch baseboards but I will run the 1 inch pex to them until they begin heading up. The house is a 1300 square ft 2 story farm house with 3 upstairs bedrooms all on one zone. Does this sound right?