Normally you will require between 30 -35 PSIG to operate a 120' coil system. Yes indeed, you must turn your pressure source off and bleed the head pressure off at the end of the day. Reset the regulator to 12 PSIG and rejuvenate the head space for storage. Over-carbonation will occur if you do not conduct this procedure.
Scott Zuhse, Instructor
Micro Matic Dispense Institute