Navien NPN-120E, User'S Information Manual

Page: 17 / 28

17 Maintaining the Water Heater
9. When the water is completely drained, reinsert
the cold water inlet filter, and then close the
water drain plug.
10. To refill the water heater follow the steps of
“Draining the Water Heater” in reverse.
4.3 Flushing the Heat Exchanger
CAUTION
Flushing the Heat Exchanger is a somewhat
complicated procedure. Read the following
instructions carefully before attempting this
procedure. If you are uncertain about any of the
steps in the procedure, contact an authorized
technician or licensed professional. Keep in
mind that improper maintenance can void your
warranty.
Refer to the “2.2 Parts of the Water Heater” on page
7 for details about part locations.
Before flushing the Heat Exchanger, gather the
following items:
Ɣ
A bucket that is 5 gallons or larger
Ɣ
Cleaning solution diluted with water
Ɣ
3 hoses
Ɣ
A water circulation pump
4. Close the water supply valve on the inlet to the
water heater. If there is no valve, turn off the
water supply at the water main.
5. Open all hot water faucets completely. The
water that remains in the plumbing lines will
drain out.
6. Open the water drain plug.
Water Drain Plug
7. Remove the cold water inlet filter.
8. Allow the residual water to drain from the water
heater.