glycol / in steam system and hammering

KBP&H_3

recently installed a 6' H-5 element in a steam system, one pipe, added a 2 1/2" tee at top of boiler . to a 2 1/2 x 1 1/4 black ell, 1 1/4" riser  w/ 2 45's to horizontal, 1 1/4 x 1 x 3/4 tee for dripping the main 2' out, 1" x 10' horizontal run w/ 7" pitch to a 1" riser to the H-5,, Hammering to the point of trouble,, this system has a glycol / yellow substance it , haven't tested it yet but seems like glycol, ?? not my original boiler install.  anyone know of anything yellow that could have been added besides glycol? anty idea for hammering,, done this many times before w/ no problem,,