New return line to boiler feed tank, problems?

Pumpguy

The attached picture shows a connection from an existing, looks like 3", return line on a 2 pipe steam heating system.

The new horizontal return line connecting to the boiler feed tank is 1.25" pipe size.

This equipment replaced the circa 1927 vacuum condensate pump that was original to the building.

These boiler feed pumps feed a pair of 30 HP boilers which replaced the original 60 HP boiler. These were chosen only because of access. Existing doorway access wouldn't allow passage of new 60 HP boiler so a pair of 30 HP boilers were chosen instead. Usual MO is to operate both new boilers together.

If you saw this piping arrangement, and knew nothing else about how the system now operates, how would you think this new arrangement would affect the overall operation of the system?

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Pumpguy

More info:

This is in a commercial / manufacturing 3 story brick building with lots of large windows. With both boilers firing, it takes about 2 hours to get the first floor to 68*F. and the 2nd and 3rd floors don't get above 50*F.

In addition, they are experiencing what I call a starve-then-flood condition with the condensate. Boilers run until boiler feed tank has to take on make up water. Then when boilers shut down all the condensate comes back, flooding the boiler feed tank.

The boiler feed tank has a 100 gallon capacity which should give at least 20 minutes of steaming time before needing to take on make up water.

So far, installing contractor's solution to this problem is to add vacuum breakers to the system. Not sure if these would be on the steam side or the return side. I'm a little confused if this has already been done, or if still in the recommended stage.

I know what I would recommend in this situation, but I'm curious what you all have to say or recommend?