Model # 460764
Alternate Part #'s PEN460764
Will a gas heater operate at the low speed of a dual speed motor?
Probably not - Most gas heater will shut off at low GPM levels (20-40) to keep the heater cores from overheating - 20 for 200 BTUs, 40 for 400 BTUs. Depending on your pool system you might get these GPM levels at the low speed but generally these heaters must be run at the motor's high speed.
what is the difference between a SR400LP and the 460764 Max-E Therm 400 BTU ASME LP?
The 460764 is a model more designed for commercial application which has a cast iron header. The rest is the same.