Gravity Hot Water System

Ken Ebers

A friend is installing a brand new gravity hot water system! Can you imagine in this day and age? Does anyone have experience in design of this type of system? The Contractor wants to pipe the supply and return into the same end of a 96" radiator. I know this won't work with forced circulation but will it work with gravity??

Mike T., Swampeast MO

I don't think so, even with supply coming from the top. Do they have a stash of Honeywell "Unique" valves or something?

Obviously a big budget or inexpensive access to big pipes and big threader!

Larry Weingarten

information

I've just finished a gravity radiant system in the walls. It even works The only source for sizing info I could find was the old books. I'd add that you REALLY need to consider flow restriction and air elimination... I'd avoid going in and out the same end of the radiator. Why take that risk? Let me know if I can help.

Mike T., Swampeast MO

Hey Larry

GREAT to hear that it works!!!!! Your designed seemed sound in principle and I [thought] it would work as planned, but it was different enough that even you didn't seem 100% certain of success...

You couldn't be more right when saying that flow restriction and air elimination are of UTMOST importance when it comes to gravity systems!

gerry gill

yes it will...

and through the same bottom opening...but you will have to field fabricate a dip tube inside a larger tee fitting..picture a 1/2'' dip tube inside a 1'' tee fitting..supply goes threw the 1/2 straight run of the tee, and out the dip tube at the other end of the radiator, and return around the dip tube and out the bull of the tee..hope this helps..by the way the original factory fitting for this was called a ''circulating coupling'' and is from about circa 1900.