A.O. Smith 12 40GPC T 100 - Manual (Page 15)

15
FILLING, DRAINING AND FLUSHING THE WATER HEATER TANK
It is recommended that the tank be drained and flushed every 6 months to remove sediment which
may build up during operation. The water heater should be drained if being shut down during freezing
temperatures. To drain the tank, perform the following steps:
Adequate Drain
Hose
Outer Door
Figure 19.
1. Turn off the gas to the water heater at the manual gas shut-off valve and turn off the electrical power to
the gas control/thermostat valve.
2. Open a nearby hot water faucet until the water is no longer hot.
3. Close the cold water inlet valve.
4. Remove the outer door and connect a hose to the drain valve and terminate it to an adequate drain or
external to the building (Figure 19).
5. Open the water heater drain valve and allow all the water to drain from the tank. Flush the tank with
water as needed to remove sediment.
6. Close the drain valve, refill the tank, and restart the heater as directed in the lighting instructions on the
front of the heater.
IMPORTANT: Condensation may occur when refilling the tank and should not be confused with a tank leak.
NOTE: If the water heater is going to be shut down for an extended period,
the drain valve should be left open.