Flushing The Heat Exchanger - Navien NPE-180A Service Manual

8.1.3 Flushing the Heat Exchanger

CAUTION
Flushing the Heat Exchanger shall be performed only by
an authorized technician or licensed professional. Read
the following instructions carefully before attempting this
procedure. Keep in mind that improper maintenance can void
your warranty.
Before flushing the Heat Exchanger, gather the following items:
A bucket that is 5 gallons or larger
●
Cleaning solution diluted with water
●
3 hoses
●
A submersible circulation
●
To flush the Heat Exchanger:
A
C
Hot Water Line
Circulation Pump
Flushing Kit
B
A
C D
Navien Plumb
Easy Valve Kit
B
D
Cold Water Line
1. Press the Power button on the front panel to turn off the water
heater.
2. Disconnect the power supply to the water heater.
3. Close the "C" and "D" valves on the hot and cold water lines.
4. Connect one tube to the "A" valve and place the free end in the
bucket.
5. Connect one of the tubes to the circulation pump outlet and
the cold water line at the "B" valve.
6. Connect one tube to the circulation pump inlet and place the
free end in the bucket.
7. Pour the cleaning solution into the bucket.
8. Open both "A" and "B" valves.
9. Turn on the circulation pump and allow the solution to
circulate through the water heater for at least 45 minutes.
10. Rinse the cleaning solution from the water heater:
a. Remove the free end of the drain tube from the bucket and
place it in the condensate drain or laundry tub (wherever the
water heater drains).
b. Close the "B" valve and open the "D" valve. Do not open the
"C" valve yet.
c. Allow water to flow through the water heater for 5 minutes.
d. Close the "A" valve and open the "C" valve.
11. Disconnect all tubes.
12. Remove the cold water inlet filter from the water heater and
clean out any residue.
13. Reinsert the filter and ensure the filter cap is securely
tightened.
14. Reconnect the power supply to the Water Heater.
15. Press the Power button on the front panel to turn on the water
heater.
Inspection and Maintenance Schedule 147