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* 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.
* The kit includes two full port isolation valves
and a pressure relief valve for the hot side.
Contact Noritz for more information.
Isolation Valves
Water Intlet
Water Outlet
Drain
Hot Water
Service Valve
Pressure Relief Valve
Cold Water
Service Valve
(Ex. NR662-OD)
Water Quality and Maintenance
For people who live in a hard water area, periodical flushing is necessary. If the Heat Exchanger is
not flushed, the Scale Build-up may cause damage to the Heat Exchanger. In this case, this water
heater will detect the Scale Build-up in the Heat Exchanger and then the error code "
"* will be
displayed in the Display Window.
When the error code "
"* is flashing in the Display Window, the Heat Exchanger needs to be
flushed to prevent damage from Scale Build-up. Please contact Noritz America for more information
about flushing the Heat Exchanger. (http://support.noritz.com/ or 866-766-7489)
* = 1, 2, 3, 4, F
# = 1, 2, 3, 4, 5, 6, 7, 8, 9, A, b, C, d, E, F
Total Hardness**
: 200 mg/L (12 gpg) or less
Aluminum
: 0.05 to 0.2 mg/L or less
Chloride
: 250 mg/L or less
Copper
: 1 mg/L or less
Iron
: 0.3 mg/L or less
Manganese
: 0.05 mg/L or less
pH
: 6.5 - 8.5
Total Dissolved Solids
: 500 mg/L or less
Zinc
: 5 mg/L or less
Sulfate ion
: 250 mg/L or less
Residual chlorine
: 4 mg/L or less
** Maximum limit suggested by Noritz.
Damage to the water heater as a result of below is not covered by the Noritz America Limited Warranty.
To ensure full warranty coverage, treat or condition water that exceeds the target levels provided in this table.
- Hard water
- Poor water quality (See the below list.)
- The water heater has displayed a "
" error code indicating Scale Build-up, but the heat exchanger
has not been flushed.
Source: EPA National Secondary Drinking Water Regulations (40 CFR Part 143.3)
