Need help repiping old gravity hot water system

bt_h2o

Hey Everyone, Please bear with me, not much of a heat guy. I have a customer with an old house that was originally gravity, at some point converted to FHW. They want to finish their basement and asked if I could repipe/raise existing piping in basement to allow for headroom. Could I eliminate existing supply and return mains and repipe basement with monoflo loop and come off loop and reconnect to risers to radiators. Is this a possibility? Will it work? Am I asking for trouble to even get involved? Thanks

JohnHenry_2

I just did the same thing to my house

Took out the old gravity pipes that hung from the ceiling in my basement. Gave me a foot and a half more ceiling height!



I used barrier pex home runs to a set of manifolds. Works better than I could have imagined.



What does the rest of the system look like? Got pictures?

The Steam Whisperer (Formerly Boilerpro)

Monoflow probably a bad idea...

the radiators were sized for all the same supply temp and with monoflow the supply temp drops as you go down the line.  Now if you install Thermostatic radiator valves on all the radiators, the monoflow will probably work because the TRV's can compensate for the changed supply water temp. Seperate home runs like described above is probably best because it keeps the water temperatures the same as original and, if using a condensing boiler, will allow you to run very high delta tees across the system with a very little pump that only uses a little electricity (say 10 watts in most homes)  The cold return temps should boost the condensing boilers efficiency measurably.  Most condensing boiler from overseas are designed for about a 30 to 35F drop, because that is the typical European standard.