Posted by Eric Boelen on June 08, 2000 at 12:34:30:
In Reply to: Maximum copper levels in low pressure steam boilers posted by Paul on June 05, 2000 at 19:15:00:
The boiler water will obviously concentrate the copper
coming from the feedwater, like it will any other impurity.
You need to check your incoming water: it is more than
likely slightly acidic, pH below 7. When this water
runs through copper piping, it will slowly but surely
disolve this copper piping. When the feedwater then
hits the high pH environment in the boiler itself,
the copper will drop out of solution and deposit as
pure copper grains. If and when there is an electrical
bridge (through piping, pipe hangers, etc) with
the copper piping then galvanic corrosion will take place
in the boiler around any copper grain that has deposited
on the steel in the boiler. It looks like O2 pitting
but the pits are inversed, they are wider at the top
than deeper in the metal. This is a non reversable
effect that can destroy a boiler in a few months.
Any time copper is used in water piping associated
with a boiler, dielectric couplings should be used
and one should pay careful attention to pipe hangers
to make sure that they cannot conduct the current.
Email me direct if you need more information regarding
Post a Followup