Circuit Board Replacement; Data Transferring Procedure; Data Transfer Troubleshooting; Initial Circuit Board Settings - Noritz NR50-OD Service Manual

<NR50-OD / NR66 (-SV,-OD) / N-0531S (-OD), NR71 (-SV,-OD) / N-0631S (-OD)>

Circuit Board Replacement

* Be sure to read.
It is necessary to transfer data when replacing a circuit board. Vital
information about the water heater such as the settings and unit history
will have to be written to the new board. Please transfer data using the
following procedure. If the transfer is not successful, the unit will not
Note: A remote controller may be necessary to complete the set-up
of the new circuit board.

Data Transferring Procedure

When a circuit board is replaced, data must be transferred from the old board, otherwise
remote controller and the unit will not operate.
After installing the new circuit board, please transfer data according to the following procedure:
1. With the electrical power disconnected, connect the new and old
circuit boards by inserting the supplied data transfer wire into
connection number CN75 (see Note 1) of each circuit board. If a temperature
selection wire is inserted into CN75 on the old circuit board, remove this
connector and save it for the new circuit board.
2. Reconnect the electrical power. The data transfer will be completed in about 30 seconds.
The unit will signal a successful transfer by rotating the fan and opening and closing
the gas solenoid valve (3 minutes).
cable connecting the new and old circuit boards.
4. If a temperature selection wire was removed from the old circuit board, reinsert it into CN75
on the new circuit board.
Note 1. The data transfer wire is marked "89", but please connect it to connection number CN75.
* After replacing the board, check and adjust manifold gas pressure settings to
listed in the "Setting list for Gas manifold pressures" table of the unit.
* When you cannot transfer data between the boards, please follow the procedures
under "Data Transfer Troubleshooting".

Data Transfer Troubleshooting

Please follow the procedure "Initial Circuit Board Settings".
2. If this is the second time that the circuit board has been replaced:
Please follow the procedure "Circuit Board Resetting".
* If data has already been transferred to the board, follow the resetting procedure.
* Once data has been transferred to a new board, the transfer procedure cannot
be performed again.

Initial Circuit Board Settings

* After replacing the circuit board, make sure all connections
are made before making the initial circuit board settings.
* When the water heater has no remote controller, make sure to connect
a remote controller before performing the initial settings below.
1. Connect electrical power to the unit and wait ten seconds before proceeding to step 2.
hit the "up" or "down" button on the remote controller and hold until the display
blinks "99". If the unit does not go into maintenance mode, unplug the unit and
try again.
3. Use the "up" or "down" button on the remote controller to change the maintenance
writer number.
4. Press the "FLOW METER ALARM SET" for 0.5 sec to change the setting ON/OFF.
5. Change "1F" from OFF to ON. (for NR50-OD, NR71 (-SV,-OD) and N-0631S (-OD) models only)
6. Change "2B" from OFF to ON.
7. Change "FE" and "FC" from OFF to ON in order to access the hidden maintenance writers.
(Display blinks with "A0".)
8. Now the maintenance writers can be accessed by hitting the "up" or "down" button
on the remote controller. Refer to the "Setting list for DIP settings" table for the
correct writer setting.
9. Press the "FLOW METER ALARM SET" for 0.5 sec to change the setting ON/OFF.
10
by pressing and holding both the "up" and "down" buttons on the remote controller
until the controller emits a beeping noise. The new settings will be lost if this is not
done.
Note 1. To cancel the settings, let the controller sit for 10 minutes,
or turn on the operation button. The information set previously
will be canceled. To change settings again, follow steps 1 through 9.
Note 2. Only change data as listed in the "Setting list for DIP settings" table.
Setting list for DIP settings
(check the rating plate for model and gas type)
Gas Type
Model
1F
NG
NR71-SV/N-0631S
LPG
NG
NR71-OD/N-0631S-OD
LPG
NG
NR66-SV/N-0531S
LPG
NG
NR66-OD/N-0531S-OD
LPG
NG
NR50-OD
LPG
Circuit board DIP setting ( :ON :OFF)
2B A1 A7 A8 A9 AB AD AE B0 B1
Reference connection diagram
Buttons for adjusting the manifold pressure settings
Connector CN75
Circuit Board Resetting
* When the water heater has no remote controller, make sure to connect a remote
controller before performing the below steps.
1. Install the circuit board into the unit and make all wiring connections.
steps 1 through 4 and step 6 of the "Initial Circuit Board Settings" procedure. This
should result in "A0" blinking on the remote controller.
"FLOW METER ALARM SET" button for 0.5 seconds to change "A0" to
4. Press and hold both the "up" and "down" buttons on the remote controller
until the controller emits a beeping noise. The new settings will be lost if this
is not done.
5. If this is a replacement board that had initial problems with data transfer, follow
the "Data Transferring Procedure".
[RC-7649M, RC-7650M]
PRI O RI T Y
Display
Please read instructions carefully
before using this appliance.
WARNING
(Writer No.)
Check actual and controller water
temperature before entering shower
or bath.
Hot Water Heater temperature
over 125 °F can cause severe burns
instantly or death from scalding.
RC-7649M
Manifold Pressure (inch H
B5 B7 B8 BC BE C1 C3 C4
"Refer to Page.83 - 87"
75
Connector Lead attached
with a New Circuit Board
for Servicing
Old Circuit Board
New Circuit Board
Setting Button
(Changing Writer No.)
UP
POWER
BURNER ON
gal .
ON/OFF
°F
Operation Button
DOWN
FLOW METER
ALARM SET
Setting Button
(Swiching ON/OFF)
2