Cause of rusted heater?

[chem geek]

Charlie,

It is low pH, not high pH, that accelerates rusting. Significantly elevated chlorine levels can accelerate corrosion, so a pool using chlorine with no CYA in the water (such as many indoor pools) would be at greater risk. If your heat exchanger in your heater is made of copper, then the rusting is most likely accelerated by the higher salt levels in the pool that are required to operate the saltwater chlorine generator (SWCG). When you get a replacement heater, get one that is more chemically resistant such as cupro-nickel or titanium. One can also use a sacrificial anode (usually made of zinc) buried in moist soil and connected to the bonding wire in order to reduce the rate of metal corrosion.

Richard

[Pool Clown]

Did the rust cause the leak? Or did the leak cause the rust? Anything the water touches (in the heater) shouldn't rust. Most everything in that heater is plastic or copper. But if the heater developed a leak, then the rust began, and, well, you know what happens then.

My guess is that the heater developed a leak (unrelated to rusting) then the rust was/is a product of the leak. Sometimes if the heater ran especially hot for long periods then cooled then hot again, the expanding and contracting can cause the transitions (from the copper exchanger to the plastic header) leak, but those kinds of environments are normally seen in commercial applications.

Note: I don't see many Mini Max NT's. But on this and other forums, I've noticed that those heaters in particular are not too popular.

Best time to get a heater? Just before you need one.