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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.
Water Intlet
Water Outlet
Drain
Hot Water
Service Valve
Pressure Relief Valve
Cold Water
Service Valve
(Ex. NRC711-DV)
Regular Maintenance-2
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)
Isolation Valves
