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BOB1901 BOB1901 is offline
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Quote:
Originally Posted by dpb
BOB1901 wrote:
....

This is a radiant floor heating system. The sys has an air
eliminator,operating pressure is around 15-20 lbs,temp is about 130
degrees and closed sys.The sys uses a hot water tank to heat the water.
I had tried anti freeze to act as a lubricant to stop the rusting of the
expansion tank (mixed a few gallons in to the sys),no luck. It seemed to
make the expansion tanks rust faster.First tank lasted about 18
months,second about 12 months ,third about 9 months. Any way of
reducing the oxygen in the water.


What does the installer say? Surely yours isn't the only one they've
done. What is unique about yours? If everybody has the same system,
they all should have similar problems. Failing help from the local
installer, have you contacted the system manufacturer for advice?
There are lots of radiant floor heating systems in use and I've not
heard of this being a generic problem so _something_ must be unique
here.

I've no direct experience w/ one of these systems, but I'm puzzled as
to how you're getting such high dissolved O2 to begin with. Is the
water heater electric, perchance, and you're getting localized boiling
off the heating elements continually generating the dissolved air? Is
there some local cavitation in pump doing something similar?

To minimize dissolved O2/air, if the system is filled and left open to
atmosphere, eventually it will come to an equilibrium point. This
could be accelerated some by pulling a slight vacuum on the system to
lower pressure (opening the pop bottle effect).

What's the rest of the piping, why isn't there a problem elsewhere in
the system? Also, replacing a steel tank (apparently unlined) tank w/
a stainless or lined one should elminate the problem from a different
angle.

I'd surely want to hear more from the system installer/manufacturer on
why I was having such problems if nobody else is--or what they're doing
for everybody if I'm not unique...

Just my $0.02, IMO, YMMV, etc., etc., ...


The sys has about 400 feet (4 separate runs) of PEX tubing (orange plastic tubing-designed for this sys,no oxygen barrier).I installed the sys (DIY),with help from manufacturer,company in Vermont,US. I spoke to them and they don't have any idea.Other sites have said the problem is no oxygen barrier in the tubing.I was told I didn't need one since I was using a gas hot water heater. Can't change the tubing so trying to find way of lowering the oxygen content.The only other idea was a plactic lined expansion tank.The problem is will the oxygen attack the copper tubing or the water heat if not that. Thanks for any help.