Quote:
Originally Posted by Indyplumber
As a licensed plumber in the US I understand the concerns about possible contamination. I assume strider is connected to city water. Even if you are using water as your medium, with a drain back tank and constant heating of the system water, bacteria can develop. If that cross-contaminates the water in his back-up water heater any pressure loss on the city side will suck that right out into the domestic water supply. Hence the backflow preventer.
Realisticly(did I spell that right?) a single wall HX should be fine for years, with PEX lasting much longer than copper. The greatest drawback with using ANY metal HX is that while the pumps are running it is eroding the metal.
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Hi,
Don't really have an issue with requiring a back flow presenter just to be on the ultra safe side. But, the water in the combination drain back/storage tank gets hot enough often enough that nothing grows in it. Mine gets up to 160F once in a while.
I don't add anything to the water in my tank, and after 3 years, its fine -- no growth.
There are lots of regular boilers that have the same kind of setup with water heated by a boiler on one side of the heat exchanger and potable water on the other side.
Gary