Water Treatment; Water Treatment System; Residential Use Treatment Guidelines - Noritz NR501-OD Service Manual

Water Treatment

If this water heater will be installed in an application where the supply water is hard, the water must be
treated with either the Noritz H2Flow or 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. In this case, this water heater detects Scale Build-up in the Heat
Exchanger and then the error code "
is displayed, the Heat Exchanger needs to be flushed to prevent damage from Scale Build-up. Refer to the
"Procedure for flushing the Heat Exchanger" or contact Noritz America for more information.
(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
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 .)
• The water heater has displayed a "
has not been flushed.
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 H2Flow and ScaleShield, contact Noritz America at http://support.noritz.com/ or 866-766-7489.

Residential Use Treatment Guidelines

Type of Water Hardness Level Treatment Device*
0-1 gpg
Soft
(0-17 mg/L)
1-3 gpg
Slightly Hard
(17-51 mg/L)
3-7 gpg
Moderately
Hard (51-120 mg/L)
7-10 gpg
Hard
(120-171 mg/L)
10-12 gpg
Very Hard
(120-200 mg/L)
> 12 gpg
Extremely
Hard
(> 200 mg/L)
NORITZ
Condensing
Tankless Gas
Water Heater
Pressure
Shutoff Valve
Relief
Valve
Drain
▲The illustration is an example. Please check with the actual water heater about the position of piping, and form.
"* will flash in the Display Window. When the error code "
" error code indicating Scale Build-up, but the heat exchanger
None
None
Once a Year*** or
H2Flow or
Flashing the error code****
ScaleShield
H2Flow or Once a Year*** or
Flashing the error code****
ScaleShield
Once a Year*** or
H2Flow or
Flashing the error code****
Water Softener
H2Flow or Once a Year*** or
Water Softener Flashing the error code****

Water Treatment System

Cold to Water
Heater
Hot Water to Fixtures
Flush Frequency**
None
None
* When selecting a treatment device, you must
** Install Noritz Isolation Valves to allow for flushing.
***Flushing is required if a water treatment
**** The error code "
Optional Sediment
Filter
Water Treatment Device
73
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.
device is not installed.
" will be flashing in the
Display Window.
= 1, 2, 3, 4, F
# = 1, 2, 3, 4, 5, 6, 7, 8, 9, A, b, C, d, E, F
Shutoff Valve
City Water Supply
"*