Installation Guide

66
18.2 Procedure for Flushing the Heat Exchanger
If the alarm code “C1#*” is flashing on the Remote Controller, it means there is Scale Build-up in the Heat
Exchanger. To prevent damage to the Heat Exchanger from Scale Build-up, the Heat Exchanger needs to be
flushed** to remove the Scale Build-up.
Damage to the Water Heater due to Scale Build-up is not covered by the Water Heater’s warranty.
To clear the alarm code “C1#*”, the Heat Exchanger must be flushed.
If the alarm code “C1#*” is displayed and flashing on the Remote Controller, contact Noritz America (1-866-766-
7489).
* Warning indication, # = 1-9
** Connect the blue connector marked “FLUSH” for flushing near the Circuit Board when flushing the Heat Exchanger.
After connecting it, the Water Heater is set to “Flushing Mode”.
NOTE
This procedure is only intended for use by a qualified service professional or authorized Noritz
Service Representative. Any unauthorized use of this procedure may result in voiding the Noritz
America Limited Warranty. Contact Noritz America (1-866-766-7489) for additional support.
NOTE
The Water Heater must remain connected to the electrical power when flushing the Heat
Exchanger.
The preparation of the flushing system
1. Close the gas supply valve.
2. Close the water inlet valve (V1) and the water outlet valve (V2).
3. Connect the one drain hose (H1) to the drain valve (V3), and then the other to the circulation pump.
4. Connect the drain hose (H2) to the circulation pump.
5. Connect the drain hose (H3) to the drain valve (V4).
6. Pour 1 gallon of “Calcium, Lime and Rust Removal Product” and 1 gallon water into the bucket.
Noritz recommends “Calcium, Lime and Rust Removal Product” for flushing.
7. Place the both drain hoses (H2 and H3) into the bucket filled with the flushing solution.
8. Open the both drain valves (V3 and V4).
Water
Outlet
Water
Inlet
Gas
Supply
V1
V3
V4
H3
H1
Water Heater
Bucket
Flushing
Solution
Circulation
Pump
H2
Gas Supply
Valve
Continue to connect
V2
* Isolation valves may be purchased as an accessory
from an authorized Noritz wholesaler. They allow for
full diagnostic testing and easy flushing of the system.
Contact Noritz America (1-866-766-7489) for more
information.
If a submersible pump is used, then only 2
hoses will be needed (H1 and H3).
Water Inlet
V1
V3
V2
V4
Water Outlet
Isolation valves* are
necessary for flushing the
Heat Exchanger.
Maintenance