Noritz EZ98DV User Manual

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17.2 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 Inlet
V1
V3
V2
V4
Water Outlet
Water Outlet Water Inlet
Gas Supply
H3
H1
Water Heater
Bucket
Circulation
Pump
H2
* 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).
Isolation valves* are necessary for
flushing the Heat Exchanger.
V1
V2
V3
V4
Continue
to connect
Gas Supply
Valve
Flushing
Solution
Maintenance

Noritz EZ98DV Specifications

General

Brand	Noritz
Model	EZ98DV
Category	Water Heater
Language	English