And you're JUST finding this thread?

The question was answered a long time ago.....


"galnorth" wrote in message
news:bda9ccd8e9dd0be22c928bf62dac3c9a@homerepairli ve.com...
32094

My expansion tank rust out in about 1 year.replaced 3 in about
years.I've been told its high oxygen in the water .How can I get rid o
it


--
BOB1901

Hello Bob,

The corrosion in your expansion tank is due to dissolved oxygen in the
fluid attacking ferrous materials including the tank, circulating pump and
any other steel or iron component. The flexible radiant floor pipe you
used
did not have an oxygen barrier to protect the system. The oxygen passes
through the wall of the tubing due to an imbalance between the closed
heating system and open oxygen rich envirnoment in our atmosphere.

If your floor heating system is connected to your hot water tank and the
DHW plumbing system just change the tank to the amtrol or equivalent
listed below. If your radiant system has a dedicated heat source in other
words it is a closed system your may have other issues and components to
change.

To eliminate your problem replace the expansion tank with a model suitable
with potable water systems such as the amtrol ST5 or ST12 and replace the
circulating pump with a bronze or stainless steel model. Your goal is to
replace any component not suitable for open potable applications. If your
system was installed by a professional plumber go back to him to remedy
this problem or if this was a DIY project then contact a radiant heating
designer at your local plumbing wholesaler for help.

If your heat source is a steel or cast iron boiler this item is also being
attacked. Your solution will also require a stainless steel heat exchanger
to isolate the tubing system from the heat source. Talk to a professional
in the future.