A.O. Smith GPVL-50 Service Handbook page 31

SYMPTOMS The water heater appears to be releasing water while the main burner is on or water is found
surrounding the heater shortly after the water heater has been used. This section explains why fl ue
gases condense and how you can differentiate between condensation and leaking.
CAUSES Condensate is the result of air borne water vapor being chilled below the dew point. The dew point
is the temperature at which water vapor turns into liquid. Low incoming water temperatures cool the
piping and the heat transfer surfaces of the water heater. When the main burner comes on, the hot
fl ue gases turn into condensate upon contact with these surfaces. The typical home water heater
will produce about one-half gallon of water vapor during every hour of operation. Condensate is
often mistaken for leaking. Newer heaters will condensate more than older heaters because modern
water heaters are much more effi cient than their predecessors. The newer heaters utilize as much
of the energy out of the main burner fl ame as possible. This lowers the fl ue gas and tank storage
temperature and closer to the dew point temperature.
THE FIX To distinguish between a condensating water heater and a leaking water heater:
1. Wipe up any water under the heater,
2. Turn gas control switch to the "OFF" position,
3. Wait 8 hours, check for water accumulation under the heater.
4. Condensation should stop when the entire tank water is heated above approximately 115°F.
a. If no water is under the heater, the water heater was condensating.
b. If water is under the heater, check further for a loose fi tting. If all fi ttings are tight and the tank
is leaking, replace the water heater. Leaking heaters cannot be "repaired".
SYMPTOMS Rusty, brown, black, or yellow water appearing in the hot water.
CAUSES 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 signifi cant
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, scientifi cally 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 levels 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 untreated portion of the piping system from re-infecting
another part. See the "Chlorination Procedure" section.
NOTES 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.
CONDENSATION
DISCOLORED WATER
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