Instructions / Assembly

35
Water Treatment
Type of
Water
Hardness
Level
Treatment
Device*
Residential Use
Flush Frequency**
Soft
0-1 gpg
1-3 gpg
(0-17 mg/L)
None None
Slightly Hard
(17-51 mg/L)
None None
Moderately
Hard
Hard
3-7 gpg
(51-120 mg/L)
ScaleShield or
Water Softener
ScaleShield or
Water Softener
Once a Year***
7-10 gpg
(120-171 mg/L)
Very Hard
10-12 gpg
(171-200 mg/L)
ScaleShield or
Water Softener
ScaleShield or
Water Softener
Extremely
Hard
> 12 gpg
(> 200 mg/L)
Once a Year***
Once a Year***
Once a Year***
Treatment Guidelines
Tankless Gas
Water Heater
* When selecting a treatment device, you must
consult with the device’s spec sheet and
installation manual for guidelines and limitations.
Not all water supplies are compatible -
a water test may be required.
**
Install Noritz Isolation Valves to allow for flushing.
***Flushing is required if a water treatment
device is not installed.
Water Treatment System
City Water Supply
Hot Water to Fixtures
Shutoff Valve
Pressure
Relief
Valve
Drain
Cold to Water
Heater
Optional Sediment
Filter
Water Treatment Device
Shutoff Valve
▲The illustration is an example. Please check with the actual water heater about the position of piping, and form.
If this water heater will be installed in an application where the supply water is hard, the water must be treat ed
with either the Noritz ScaleShield or a water softener. Refer to the below tables for suggested treatment and
maintenance measures to be taken based on the water hardness level. If this water heater will be installed
in an application where the supply water is hard, Scale Build-up may cause damage to the Heat Exchanger.
To prevent damage to the Heat Exchanger, the Heat Exchanger regularly needs to be ushed.
Refer to the "Procedure for ushing the Heat Exchanger" on page 37 or contact Noritz America for more
information. (http://support.noritz.com/ or 866-766-7489)
This water heater is equipped with an automatic service reminder to announce for ushing the Heat
Exchanger. The factory default of this service reminder is OFF. The customer or installer needs to set
the service reminder to ON or OFF. Refer to the "How to select the Service Reminder" on page 36.
If the service reminder is selected to ON, the code "C1#*" will displayed on the remote controller after
the set time period has been reached. When the code is displayed, the Heat Exchanger needs to be
ushed to prevent damage from Scale Build-up.
* # = 1, 2, 3, 4 ... 9
Damage to the water heater as a result of the items below is not covered by the Noritz America Limited Warranty.
• Water in excess of 12 gpg (200mg/L) of hardness
• Poor water quality (See the Water Quality List on page 34.)
• The water heater has displayed a "C1# (Service Reminder)" indicating Scale Build-up, but the heat
exchanger has not been ushed.
Note: Water softeners may be regulated by the local water jurisdiction, consult with the manufacturer for
code, sizing, and installation guidelines; the below diagram is for reference only. For more information
about ScaleShield, contact Noritz America at http://support.noritz.com/ or 866-766-7489.