If all the zones are coming back equally hot then the floor that having problem heating might be short on radiation and might have to install more base board footage
cause your water is leaving plenty hot out of boiler being at 180-200
Can you tell us the make and model of the circulator?( the motor that one of the other experts asked about) It will be close to the boiler on either the supply or return pipe and will have a wire running to it. Anything you cann tell us about it would be helpful because I think you do not have enough pump for the job.