Draining The Unit And Cleaning The Inlet Water Filter - A.O. Smith Water Heater 520 Direct Vent Indoor Service Manual

12-21. Draining the unit and cleaning the inlet water filter

1.
Close the manual gas shut off valve.
2. Turn off power to the 520 Indoor or 520 Outdoor, wait a few seconds. And then turn on again.
3.
Wait 30 seconds for water valves starts to completely open. Then turn
off power to the 520 Indoor or 520 Outdoor, yet again.
4.
Close the water shut-off valve.
5. Open all hot water taps in the house. When the all
water flow has ceased, close all hot water taps.
6.
Have a bucket or pan to catch the water from the drain
plugs of the 520 Indoor or 520 Outdoor. Unscrew the drain
plugs to drain all the water out of the 520 Indoor or 520
Outdoor.
7. Wait a few minutes to ensure all water has completely
drained from unit.
8. Clean the filter: Inspect the water filter located within
the cold inlet. With a tiny brush, clean the water filter
of any debris which may have accumulated and
reinsert the filter back into the cold water inlet.
9. Securely screw the drain plugs back into place. Hand-
tighten only.
520 Indoor / 520 Outdoor Service Manual
Drain Plug
(Small)
88
CONFIDENTIAL
Ver. 1.00
Drain Plug
with Filter
Drain Plug
(Large)
Water Valve
Gas Valve