pipe coils

able

hello I looked at a job today a old factory exterior walls have 1 1/2 inch 5 row coils feed by 2 1/2 inch pipe returns are 1 inch no steam trap they have a swing check there are vents on the header of coil is there a orfice in the valve they want to replace the boiler it is about 6 foot in diameter has a 4 inch supply no hartford loop or equalizer any sugestions would be greatly appreciated thanks