Rheem P-M266 is the unit he would source. His experience is that the natural draft design tends to last much longer (not as tough on the heat exchanger). Also mechanically simpler (less parts/sensors with no blower).
Rheem P-M266/ RayPak P-M266, same heater by the same manufacturer with the same parent company (American Standard). Have never seen a "consumer" nor "trade-grade" model of any of their heaters. I can acutally source either RayPak or Rheem through one of may suppliers.
With proper care the RayPak atmospheric will last as long as any other, I still do work for customers that have a 10-15 year-old RayPaks that I installed with no issues. Older RayPaks did, indeed, have rust issues, partially because they was very little room below them (they sit on small risers on the bottom) and debris would build, never get cleared, hold moisture and rust from the outside. New atmospheric models sit on taller risers. If rust is an issue with atmospherics, it may be because LoNox heaters (heaters with blowers) are able to literally blow moisture from the cabinet, and many, like the Avia, MasterTemp, Max-E-Therm, have sealed combustion chambers.
Avia sits directly on the pad. Avia is very new and hasn't a long track record yet. Cost of repair is less on an atmospheric heater like the P-M266 as it is a simpler design with virtually no moving parts (blower, air switch, etc.)
Some pool guys just aren't comfortable installing something they aren't very familiar with. If you want the Avia, insist on it. Your pool, your money, your choice.
www.raypak.com
www.harwil.com
www.troublefreepool.com
