Expansion Tank Location

Bruce M.

On a boiler that has the circulators on the supply side is it better to have the Extrol tank before the circulator on the supply or on the return close to the boiler?

jim lockard

Supply

Bruce I like to hang the exp. tank under the air scoop on the supply side after the boiler and before the circulators. This setup allows me to connect the water fill at the exp. tank and place my isolation and purge valves on the return.

Big Ed

Pipe wise

Some install it on the return just before the boiler to give a "lag" where air has time and volume to come out of solution. But I find it awkard piping wise unless the boiler is sitting high up ,like a buderus sitting on hot water heater...

jim sokolovic

Jim, that piping method...

doesn't allow you to purge the boiler itself, if you think about it. Better to have the purge valve on the supply pipe with the isolation valve right after it (both just before the air scoop / fill / expansion tank). Then the entire system can be purged from a single valve, without leaving pockets of air in any dead areas.