Noritz NR501-OD Service Manual page 36

B
Check whether the manifold gas pressure is normal.
Normal Abnormal
Check whether the manifold gas
pressure can be adjusted.
Impossible
3
Check the voltage of the Gas
Proportioning Valve.
Normal
CN10:Between Red 4 - Blue 3
When adjusting the manifold gas pressure,
the voltage changes within the range DC 0.3 - 15V.
Circuit Board
1
2
3 BL
4 R
5 W
6
O
7 GY
8 BK
9
10
W
11 BL
12
13 W
14
15
BL
<CN10>
During combustion, press and hold both "Maximum and Minimum Manifold Pressure
Set Button*" and check whether all the burners are burning .
Normal
* The procedure of Manifold Gas
Adjustment is described in page 24.
Check the voltage of Gas Solenoid
Valve-1 (SV1), Gas Solenoid Valve-2 (SV2)
a n d G s a S o e l n o d i V l a
Normal
1 SV1 CN 10
DC1-16V
SV2 CN 10
2
DC1-16V
3 SV3 CN 10
DC1-16V
Circuit Board
1
2
3 BL
4 R
5
W
6 O
7 GY
8 BK
9
10
W
11 BL
12
13 W
14
15 BL
<CN10>
Check the Gas Proportioning Valve.
Check in the same procedure as
Po ssible
Abnormal
14
12 W
13
11 Y
12 BL
10 O
11 W
9 R
10 R
8
9 Y
7
8
Main
6 BK
7
5 V
6 Circuit
BK
4 G
5 BK
Board 3 O
4 W
2 Y
3 W
1 W
2 BK
<CN59>
1 W
1
<CN63> 2
1 2 3
3 4 3 2 1
4 BL
<CN135>
4 R
3 BL
BR Y BL R
5 O
2 BL
<CN27>
6 Y
1 R
7 W
<CN142>
<CN104>
<CN78>
2 3 R
1
1
BL 2
2 BL
3 BL
4 R 1 G
5 W
<CN101>
6 O
7 GY
8 BK <CN10>
9
10 W
<CN89B>
11 BL
3
12
2
6 BK 13
W
1
5 R 14
15 BL <CN75>
4
3 2 1
3
2 W
BL/W R/ R G
1 W
<CN42> <CN89A> <CN102>
Check for improper connection of wiring,
then replace the Gas Proportioning Valv
Abnormal
Abnormal
e v 3 - S ( V 3 . )
: Between Black 8 - Blue 11
: Between Gray 7 - Blue 11
: Between Orange 6 - Blue 11
14
12 W
13
11 Y
12 BL
10 O
11 W
9 R
10 R
8
9 Y
7
8
Main
6 BK
7
5 V
6 BK Circuit
4 G
5 BK
Board 3 O
4 W
2 Y
3 W
1 W
2 BK
<CN59>
1
W
1
<CN63> 2
1 2 3
3 4 3 2 1
4 BL
<CN135> 4
R
3 BL BR Y BL R
5
O
2 BL
<CN27>
6 Y
1 R
7 W
<CN142>
<CN104>
<CN78>
2 3 R
1
1
BL 2
2 BL
3 BL
4 R 1 G
5 W
<CN101>
6 O
7 GY
8 BK <CN10>
9
10 W
<CN89B>
11 BL
3
12
2
6 BK 13 W
1
14
5 R
15
4 BL <CN75>
3 2 1
3
2 W
BL/W R/ R G
1 W
<CN42>
<CN89A> <CN102>
3.
36
Recheck after adjusting
the manifold gas pressure.
* The procedure of Manifold Gas
Adjustment is described in page 24.
Replace the Circuit Board set .
* It is not necessary to replace the
Display Window Circuit Board.
Display Window
Fuse
Circuit Board
Data
Displ ay
W 3 1 W
BK 4 2 BK
Po wer
Circuit <CN92>
Board
Dip Switch
1 2 3 4
R BL BL BL
<CN142>
Replace the Circuit Board set.
* It is not necessary to replace the
Displ ay Window Circuit Board.
Display Window
Fuse
Circuit Board
Data
Displ ay
W 3 1 W
BK 4 2 BK
Po wer
Circuit <CN92>
Board
Dip Switch
1 2 3 4
R BL BL BL
<CN142>
Check for the Water Flow Sensor
or w s.
e.