Proposal to

Fizz

overcome excess edr.  See attachment.  Steam guy doesn't want to replace pipes with larger pipes, feels it's too invloved, suggests re-routing lateral B off branch to new branch off main.  Connected EDR to current branch(A) is 82, the laterals are 3/4" except for C which is 1".  By doing so connected EDR to A would be reduced to 44, with 38 connected to propose piping.  Reason for seeking a fix is that only rad off C heats well at all times, other 3 will heat together if valves on rads off B are opened slightly, and rad on D opened all the way, however, rads off B will heat minimally, and D slightly better.  If the rad off B are opened more, then D doesn't heat.  Any feedback appreciated.

jumper

easier

Easier to enclose rad that's too big.

Charlie from wmass

How about changing air vents

If you use Vent Rite #1 adjustable vents and slow down the larger rads vent speed and adjust the others as needed.

Fizz

My bad

should have specified, it's a 2 pipe, Richardson System,  However, the second rad attached to lateral B was an add-on, with a traditional trap.  The valve is throttled back to about 10% of supply range. 

Fizz

There really is no

large radiator involved in the 4 mentioned.  Largest EDR is 24, lowest 16.