Circuit Board Replacement Procedure; Data Transfer Procedure; Dip Switch Settings - Noritz NR501-OD Service Manual

When swapping in a new circuit board, the new circuit board needs to be programmed.
Failure to successfully program the circuit board will result in a 73 error code.
Typically this programming can be done with a data transfer from the old circuit board to the new circuit board.
Even a damaged circuit board can usually transfer data properly.
Always attempt the data transfer first, and if unsuccessful, retry the data transfer procedure.
Only if the data transfer is unsuccessful, then you should follow the procedure for manual programming on the reverse side of this page.

1. Data Transfer Procedure

( for illustration only )
various connections
to unit
water
heater
new circuit
unit
board

2. DIP Switch Settings

*Disconnect the electrical power to the unit before adjusting the DIP Switches.
DIP Switch Settings are set to the same as the old circuit
The following settings can be adjusted using the DIP Switches.
1. By setting DIP Switches 1 and 2, the unit can be programmed to different default temperatures
if the remote controller is removed.
2. (-DV Model only) By setting DIP Switch 3, the intake air supply type can be set to
direct vent(DV) or non-direct vent(SV).
3. By setting DIP Switches 5 and 6, adjustments can be made for high elevation installations.
4. By setting DIP Switches 7, adjustments can be made for extended vent lengths installations.
Refer to the "Setting list for DIP Switches" table for details.
OFF
ON

Circuit Board Replacement Procedure

1. If the remote controller is connected,
make sure the remote controller is off
( completely blank ), If it is ON, turn it
OFF and wait for 10 seconds.
2. ...then disconnect electrical power.
3. Remove old circuit board out of the unit
and install new circuit board to the unit.
Then transfer all electrical connections
display window circuit board to the new
circuit board.
4. Use the blue and white data transfer cable supplied
with the new circuit board to connect the CN75
connection from the old circuit board to the new one.
note) The date transfer wire is marked "89",
but please connect to "75" connector.
data transfer cable
linking CN75 connection
old circuit
board
5. Connect power and wait about 30 seconds
to a minute. The unit will signal a successful
data transfer by spinning the fan and opening
and closing the gas valve for about 3 minutes.
If you get a successful data transfer: disconnect electrical power to
the unit, disconnect the data transfer cable.
Manifold pressures should be checked with a digital manometer and
adjusted if necessary.
Refer to the "Setting list for MW settings and Gas manifold pressures"
at reverse side.
If you fail to get a successful data transfer, refer to the
reverse side for Manual Programming.
When replace only the circuit board, it is not necessary following procedures.
Setting list for Dip Switches
1 2 3
Intake Air
Default temperature
supply type
setting
-DV Model only
1 2 3 Intake Air supply
120°F (50°C) Outdoor : DV
130°F (54°C) Indoor : SV
135°F (57°C)
140°F (60°C)
note) The unit is fixed with minimum combustion, if you change No.4 to ON. It is possible to cause
the trouble, please do not change it. No.8 does not have any function.
Stopper
Display window
circuit board
New
Circuit
Board
Connector CN75
board.
( :ON :OFF )
5 6
Elevations above 2,000ft
-DV(-SV) Model only
High Elevation Adjustment
5 6 7
0~2,000ft (0~610m)
2,001~4,000ft (611~1,220m)
4,001~6,000ft (1,221~1,830m)
6,001~8,000ft (1,831~2,440m)
61
Press the stopper and slide to the direction of the
arrow to remove display window circuit board
from old circuit board and reinstall it to the new
circuit board in the reverse procedure above.
Old
Circuit
Board
Connector CN75
Connect data transfer cable to transfer
the data from the old circuit board to
the new circuit board (see Step 4)
7
Vent Length
Adjustment
Vent Length
Short Length
Long Length