Boiler air baffle

mjstraw

Burnam Holiday boiler from mid-70's (?) with internal air separating baffle piped to steel compression tank.  Works well - I've only had to drain the tank twice in 20 years.

Getting ready to add second zone using an additional circulator.  @DanHolohan's "Piping Away" book says boiler baffles don't work well with multiple circs.

I could add an air separator piped to the tank, or switch to a bladder tank and air elimination. But I envision a large bubble of air trapped behind the baffle from when only one circ is running.

Will this be a problem?

JUGHNE

What pages refer to this situation?

mjstraw

Page 57

JUGHNE

So then your system would look like page 59, with circs instead of zone valves.
I have never dealt with this situation; IDK....someone else here later in the day may respond.

Is your old tank original from the 70's? 45-50 years old.
Bladder tank will not last that long.
FIWM, I would put an isolation valve on the new tank....easier to test and change.

Do you have CI rads? The water content of the system determines the size of a new bladder tank.

mjstraw

Yup, CI roads.  2.5in mains, 2-pipe direct return.  Compression tank could even be from previous boiler, IDK.

Some idiot removed rad from kitchen and replaced with fin tube baseboard.  Last connection off mains, kitchen always cold.  Will be putting kitchen on it's own zone, adding kickspace heater if necessary.