Dave, I understand what you are talking about, and have read similiar facts in trade manuals and the like. But I dont understand why the manufacturer of the heater would say it requires a 15 amp dedicated circut if it only is rated for 1500 watts (which is on the UL label on the back of the heater).
No worries, I will have the heater on it's own circut (all of Bus2) and wont have any issues with it.