converting a wet return one-pipe to a boiler feed pump system

kcny

I replaced a large boiler on a one-pipe steam system that had a wet return with a new sectional boiler that matched the load for the radiation that was being used in the building. I used a boiler feed pump system with about a 23 gal. tank. The radiators have adjustable air vents for temperature control. We started it up and had too much steam out of the vent on the tank. It would take a lot to run the vent up three floors to the roof. I don't believe this is the answer. It is possible to put a f&t trap on each of the return pipes that come to a common return, but this would be about 32 hrs. of labor and about $1,000-$1,500 to do and I still think the water temp. coming back will flash off to steam and/or because the system is only running 11/2-2#, there might not be enough differential on the traps for them to work. The installation is perfect in quality, but this problem may make a mess of the whole thing. I need to ask everyone experienced in one-pipe steam if I have made a mistake creating an open system, or can I fix the problem?

Steamhead

Is the pump really needed?

Assuming the vents are properly sized, you might be able to do away with the pump. If not, you'll have to put an F&T on every drip to keep steam out of the pump. Or you can use a False Water Line, as explained in Lost Art.

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

DanHolohan

I'd agree!

Unknown

Boiler feed pump?

Installing a boiler feed pump on a one pipe steam system will cause the problems you have if the you do not isolate the the boiler from the feed pump system.

If you need to keep the feed pump steam traps have to be installed at the end of each steam main. Additionally you may have to install steam traps at the base of each steam riser.

The questin here is why was the feed pump system installed?

If the previus installation did not have a feed pump why was a feed pump needed in the new installation.

Feed pumps or condensate pumps are installed when condensate cannot return to the boiler in a timely manner.

If condensate does not return to the boiler fast enough the boiler will go out on low water. If a automatic feed valve is installed on the boiler and condnesate lag is present the boiler and or piping system will flood.

Unless there something unusual about the new boiler remove the feed pump and restore the original return piping to the new boiler.


jake