Anode Rod Inspection; Draining And Flushing; Recommended Procedure For Periodic Removal Of Lime Deposits From Tank Type Commercial Water Heaters - A.O. Smith BTN-120 Instruction Manual

anode rod inspeCtion

CAUTION
Property Damage Hazard
•
Avoid water heater damage.
•
Inspection and replacement of anode rod required.
The anode rod is used to protect the tank from corrosion.
Most hot water tanks are equipped with an anode rod. The
submerged rod sacrifices itself to protect the tank. Instead of
corroding the tank, water ions attack and eat away the anode
rod. This does not affect water's taste or color. The rod must be
maintained to keep tank in operating condition.
Anode deterioration depends on water conductivity, not
necessarily water condition. A corroded or pitted anode rod
indicates high water conductivity and should be checked and/
or replaced more often than an anode rod that appears to be
intact. replacement of a depleted anode rod can extend the
life of your water heater. Inspection should be conducted by
a qualified technician, and at a minimum should be checked
annually after the warranty period.
Artificially softened water is exceedingly corrosive because the
process substitutes sodium ions for magnesium and calcium
ions.
The use of a water softener may decrease the life of the water
heater tank.
The anode rod should be inspected after a maximum of three
years and annually thereafter until the condition of the anode
rod dictates its replacement.
note: Artificially softened water requires the anode rod to be
inspected annually.
explosion hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASMe code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.

draining and flushing

It is recommended that the water heater storage tank be drained
and flushed every 6 months to reduce sediment buildup. The
water heater should be drained if being shut down during freezing
temperatures. See Features And Components in this manual for
the location of the water heater components described below.
to drain the water heater storage tank:
1. Turn off the electrical supply to the water heater.
2. Turn off the gas supply at the Main Gas Shutoff Valve if the
water heater is going to be shut down for an extended period.
3. ensure the cold water inlet valve is open.
4. Open a nearby hot water faucet and let the water run until
the water is no longer hot.
5. Close the cold water inlet valve to the water heater.
6. Connect a hose to the water heater drain valve and terminate
it to an adequate drain.
7. Open the water heater drain valve and allow all the water to
drain from the storage tank.
8. Close the water heater drain valve when all water in the
storage tank has drained.
9. Close the hot water faucet opened in Step 4.
10. If the water heater is going to be shut down for an extended
period, the drain valve should be left open.
to flush the water heater storage tank:
1. Turn off the electrical supply to the water heater.
2. ensure the cold water inlet valve is open.
3. Open a nearby hot water faucet and let the water run until
the water is no longer hot. Then close the hot water faucet.
4. Connect a hose to the drain valve and terminate it to an
adequate drain.
5. ensure the drain hose is secured before and during the
entire flushing procedure. Flushing is performed with system
water pressure applied to the water heater.
6. Open the water heater drain valve to flush the storage tank.
7. Flush the water heater storage tank to remove sediment and
allow the water to flow until it runs clean.
8. Close the water heater drain valve when flushing is completed.
9. remove the drain hose.
10. Fill the water heater - see Filling The Water Heater in this manual.
11. Turn on the electrical supply to place the water heater back in
operation.
12. Allow the water heater to complete several heating cycles to
ensure it is operating properly.
reCommended proCedure for periodiC
remoVal of lime deposits from tank type
CommerCial water heaters
The amount of calcium carbonate (lime) released from water is
in direct proportion to water temperature and usage, see chart.
The higher the water temperature or water usage, the more lime
deposits are dropped out of the water. This is the lime scale
which forms in pipes, heaters and on cooking utensils.
29
Burn harzard.
Hot water discharge.
Keep hands clear of drain
valve discharge.