A.O. Smith TC-049R3, Руководство по обслуживанию

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RESIDENTIAL GAS AND ELECTRIC WATER HEATER
SERVICE HANDBOOK
TECHNICAL BULLETIN
BULLETIN 21
DISCOLORED WATER
SYMPTOMS
Rusty, brown, black, or yellow water appearing in the hot water.
CAUSE
Complaints of discolored water are commonly blamed on water heaters and
storage tanks, but in fact, it is a rare occurrence for today’s high quality glass
lined tanks to have a lining failure significant enough to allow water to contact
enough bare metal to discolor the contents of even a small tank.
The most common cause of “rusty” water is a non-toxic iron reducing bacteria,
scientifically termed Crenothrix, Leptothrix, and Gallionella. Iron bacteria is
commonly found in soil, water wells, water treatment plants and water
distribution piping systems where soluble iron exceeds 0.2 ppm, higher levels
make conditions even more favorable. Soluble iron in the water provides food
for the bacteria. Rusty discolored water is the end result of the bacteria feeding
process. Water heaters and storage tanks usually require new anode rods as
presence of iron bacteria contributes to premature anode failure.
The requirements for the bacteria to thrive are:
•
Elevated level of iron and manganese in the water
•
Water with little or no dissolved oxygen
•
Temperatures below 138
°
F
Items that can increase the potential for this bacteria are:
•
Water softeners
•
Well water
•
Long periods of no water movement
TREATMENT
The simplest treatment available is shock-chlorination of the system. This is a
surface treatment, and often requires repeated trials in heavily infected
systems. The chlorination of a system requires that you follow each step
explicitly to avoid an un-treated portion of the piping system from reinfecting
another part. See Bulletin 23 for the chlorination procedure.
NOTE
Since rusty water is caused by a bacteria presence and is not caused by the
water heater, any treatment would not be considered warranty related.
A.O. Smith Water Products Company Technical Training Department
©
2005 Ashland City, TN
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