Outlet Water Temperature Incorrect - Noritz NR501-OD Service Manual

1-3. Outlet water temperature incorrect

Only connect and disconnect the connector after the fan has stopped rotating and then disconnect the electrical power.
(The Circuit Board and Fan Motor may be damaged otherwise.)
Check whether 2 dots (r
In this case, the actual outlet water temperature is colder than the Set Temperature .
rm "Thermistor-Hot W ater", " Water Ser vo-Main", "Manifold Pressure", "Gas Solenoid Valves / Proportioning Valve" are normal.
Check whether the Thermistor-Cold Water / Hot Water / Heat Exchanger are normal.
Normal
Disconnect electrical power,
and then open the xture ( ow
water through the unit).
Close the xture, and then
reconnect electrical power.
Check the maintenance
monitor.
The d erence between # 30
and # 31 and # 32 data should
be within ±5 ˚F .
Check that the Thermistor-Hot Water is normal with the outlet water conditions.
Normal
Tu rn the unit on, and then set
the temperature to "100 ˚F" and
"140 ˚F" by using Remote
Controller*.
Open the hot water xture full y,
and then con r m
Thermistor-Hot Water by the
maintenance monitor.
# 31 data should be within
±5 ˚F of the set temperature.
* Only when Remote Controller
is connected.
No abnormality in appliance.
ay Window.
Abnormal
Check the thermistor resistance.
Normal
1 CN63 White 4 - Black 2 (Cold Water)
2 CN63 White 1 - Black 2 (Hot Water)
3 CN63 White 3 - Black 2 (Heat Exchanger)
Ref er to the thermistor temperature characteristics below.
Circuit Board
14 14
13
12 BL
13
11 W
10 R
9 Y
12 BL
8
Main
7
11 W
6 BK Circuit
5 BK
Board
4 W
10 R
3 W
2 BK
9 Y 1
W
<CN63>
1 2 3
8
<CN135>
7
6 BK
<CN78>
2
5 BK 1
1
BL 2
3 BL
4 W
4 R
5 W
6 O
3 W
7 GY
8 BK <CN10>
2 BK
9
10 W
11 BL
1 W
12
6 BK 13 W
14
5 R
15
4 BL
3
<CN63>
2 W
1 W
<CN42>
Abnormal
2
Check the Wa ter Servo-Main is normal.
(Check the maintenance monitor # 60.)
Maintenance monitor # 60
[000] - [170] : Normal ("1700" is displayed on the Remote Controller)
Check whether the maintenance monitor # 60 moves between [000] and
[170].
[EEE] : Abnormal
Check for improper connection of wiring, then replace the Water
Servo-Main.
Check whether the primary gas pressure is normal.
Abnormal
Normal
* Check the primary pressure (dynamic pressure)
at the time of maximum combustion.
B
35
Abnormal
Check for improper connection of wiring,
connectors, etc., then replace the thermistor.
When measuring the resistance, disconnect
the connector and check the male side.
12 W
11 Y
10 O
9 R
8
7
6 BK
5 V
G
4
3 O
2 Y
1 W
<CN59>
1
2
3 4 3 2 1
4 BL
4
R
3 BL BR Y BL R
5
O
2 BL
<CN27>
6 Y
1 R
7 W
<CN142>
Po wer
<CN104>
Circuit
3 R
Board
2 BL
1 G
<CN101>
<CN89B>
3
2
1
<CN75>
3 2 1
BL/W R/ R G
<CN89A> <CN102>
Replace the Circuit Board set.
* It is not necessary to replace the
Displ ay Window Circuit Board.
Primary gas pressure list
Gas group
Pressure
Maximum
pressure
Standard
pressure
Minimum
pressure
Display Window
Fuse
Circuit Board
Data
Displ ay
W 3 1 W
BK 4 2 BK
<CN92>
Dip Switch
1 2 3 4
R BL BL BL
<CN142>
Check the gas supply valve, etc.
LP NG
inch H O 14.0 10.5
2
inch H O 11.0 7.0
2
inch H O 8.0 4.0
2