problems with copper forced water loop run above water line of steam boiler. Any Ideas?

Joseph_4

Hi.. I have a customer that I ran a loop for his attic through the bottom of steam boiler in the summer. with a pump. set up properly with drain cocks on both sides and valve to fill sytem using water heater. and having static pressure of boiler water to keep water in that zone in the loop. When i fill up it runs fine and heats. all piping to to and from loop is copper. I have 2 check valves below water line. after about a month he gets banging in the new attic loop. i dont understand why this is happening because the water line is above the both drain cocks and the return and supply is literally a good foot below the water line maybe 2 feet.

Has any one had this problem?

How can I fix?

thx

Joseph Hardoon

HHI Services LLC

Jamie Hall

There is, inevitably, a certain amount of air in the boiler water. At the very absolute pressure up at the top of that loop, that air will gradually come out of solution and form air pockets up there.

The only real solution to this is to use a neat exchanger and pressurize that attic loop, just as you would a conventional hydronic system. However… if there is a domestic hot water coil on the boiler, you could pressurize that loop and use the domestic hot water coil — assuming you are not using it for anything else.

Joseph_4

This kind of setup i believe was the "poor man's" way to go.. i heard many on this site have done it. Its on the last page (80)of Dan's Golden Rules. Does it make a difference how highup on system i put the check valves/flo control valves

thx

Joe

EBEBRATT-Ed

I think two floors is maximum height. You could have a valve somewhere just a little leak around a packing nut would do it. Check the suction side of the pump with a gauge to see if it is in a vacuum.

Mad Dog_2

Did you put a bypass in to blend the condensate down? Pictures or sketch ? Mad Dog

Jamie Hall

Check valves should be as low as possible.

That said, yes it can be done. It is called a poor man's solution for reason… it will work. Sometimes. For a while. Until it doesn't. It's better to do it right…

Joseph_4

I did make a bypass. could it be turning to steam… why does it work for a few days? i didnt put an auto air vent in upper floor cause i figured if im purging all on start up, then shouldnt take on air.

Thanks

Joe

HHI