Abnormally High Output Temperature; High Limit Switch Triggered - Noritz NR501-OD Service Manual

Error Codes
Display Remote
Window Controller

Abnormally high output temperature

161, 162, 163 16
Check the Thermistor - Hot Water resistance.
Normal
CN63 : Between White 1 - Black 2
Refer to the thermistor temperature
characteristics belo w.
When measuring the resistance,
disconnect the connector and
check the male side .
Check the Gas Proportioning Valve .
Normal
Check for the Water Servo Main.
Normal
Error Codes
Display Remote
Window Controller

High Limit Switch triggered

20 20
Check the High Limit Switch resistance .
Normal
CN10
Between White 13 - White 5
1 or less.
When measuring the resistance ,
disconnect the connector and
check the male side.
Description
Abnormal
Circuit Board
14
14
13
13
12 BL
11 W
12 BL
10 R
9 Y
8 Main
11 W
7
Circuit
6 BK
10
R 5 BK
Board
4 W
3 W
9 Y
2 BK
1 W
8
<CN63>
1 2 3
<CN135>
7
6 BK
<CN78>
5 BK
2 1
1
4 W BL 2
3 BL
4 R
3 W
5 W
6 O
7
2 GY
BK
8 BK <CN10>
9
1 W
10 W
11 BL
12
6 BK 13 W
14
5 R
<CN63> 15 BL
4
3
2 W
1 W
<CN42>
It is shown on page 7 ( 3).
It is shown on page 6 ( 2).
Description
Abnormal
Circuit Board
14
13
1
12 BL
11 W
2
10 R
9 Y
3 BL
8
Main
7
4 R
6 BK Circuit
5 BK
Board
5 W
4 W
3 W
6 O
2 BK
1 W
7 GY
<CN63>
1 2 3
8 BK
<CN135>
9
10
W
<CN78>
11 BL
2
1
12 1 BL 2
3 BL
13 W 4 R
5 W
14 6 O
7 GY
15 BL 8 BK <CN10>
9
10 W
<CN89B>
11 BL
<CN10>
12
6 BK
13 W
5 R 14
15
BL
4
3
2 W
1 W
<CN42>
<CN89A>
41
12 W
11 Y
10 O
9 R
8
7
6 BK
5 V
4 G
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
6 Y <CN27>
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
<CN102>
<CN89A>
Check for improper connection of wiring.
Replace the Thermistor - Hot Water.
Replace the Circuit Board set .
* It is not necessary to replace the
Display Window Circuit Board.
12 W
11 Y
10 O
9 R
8
7
6 BK
5 V
4 G
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>
3
2
1
<CN75>
3 2 1
BL/W R/R G
<CN102>
Check for improper connection of wiring .
Replace the High Limit Switch.
Check for the Heat Exchanger-Primar y is normal.
(ex. The surface discolors black, clogging, etc.)
Replace the Circuit Board set.
* It is not necessary to replace the Display
Window Circuit Board.
Displ ay Window
Fuse
Circuit Board
Data
Display
W 3 1 W
BK 4 2 BK
<CN92>
Dip Switch
1 2 3 4
R BL BL BL
<CN142>
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>