I wanted to warn fellow pool/spa owners of the dangers in purchasing ANY Ray Pak products online. Bottom line is once you purchase you are on your own. Factory defect? Too bad. They will not even respond to your emails and their phone number is not published. Just read their "internet purchase policy" section of their own website. After reading that I found that Ray Pak sells heaters online themselves through Amazon! What hypocrites!
I purchased a model 266A millivolt heater in Feb. 2010 to replace another Ray Pak millivolt heater that was over 30 years old. I figured why mess with something that works. Right? Well four years in this 266A blows a hole through one of the water tubes right under the fins that are pressed onto the tubes. What a piece of junk! And now they want almost $600 for just the part? I will braze it myself first!
This is a millivolt heater. One gas line and two water lines to complete installation outdoors. There are no "special instructions" as Ray Pak claims to install this heater.
Do yourself a favor and buy another brand!