Multiple (triple) Steam Boilers with Reservoir Tank

We took out a leaking commercial boiler that had a condensate tank and replaced it with 3 smaller semi-commercial boilers. We did this to provide a way to have multiple firing rates based upon system pressure. Also the benefit of redundancy exists this way. Someday a boiler will stop working but they will still have heat from the other two. For an apartment building that makes much more sense than one large boiler. Somewhere down the life of the building the wet returns were made dry. We removed all the F&T traps and restored the wet returns by using a false water line and adding air vents to the system. The three semi commercial boilers didn't have the water in the operating range that the original commercial boiler did so we installed a reservoir tank to provide the amount of water needed for steaming. This is a passive tank in that there are no pumps, controllers etc. that go with it. It works purely by the physics of the system. We wanted the feeder to be capable of being called upon by any of the three boilers so a relay system was employed to make this operate.

BEFORE PICTURE...F&T trap at mains end.

BEFORE PICTURE...Another F&T trap at the end of a main.

BEFORE PICTURE...The old commercial boiler. Condensate tank with a master trap F&T trap preceeding it.

The three replacement boilers.

Another view.

View showing the drain piping.

Another view of the three boilers with a sneak look at the reservoir tank in the background.

Close up of the boiler drop headers.

View of the system takeoff side of the main header. Note the new ceiling.

How the flues tie together.

This view shows the reservoir tank placement.

The main drop header that supplies the system take offs.

Extra water is supplied by this reservoir tank.

Reservoir tanks water level.

How the reservoir tank ties into the wet return.

Another view of the tanks tie in to the return piping.

Nate and the reservoir tank.

Equalizer to the reservoir tank.

Another view of the tanks equalizer.

Front view of tank.

Closer view of false water line piping.

False water line piping behind tank.

Control station.

Control station.

Relay that operates the three boilers.

Relay that operates the feeder.

Relay that operates the feeder.

Main air vent station.

Zone valve that air locks the return pipes until steam makes it thru the supply mains.

End of steam main vents and the trigger aquastat for the return pipe vents.

Pajek pressure contoller.

Pajek controller is the low fire trigger.

Another view of the Pajek Pressure Contoller.