50
Check the Dip Switch settings.
Check whether the
s
e
r
p
s
a
g
y
r
a
m
i
r
p
sure is normal.
Check whether the manifold gas pressure is normal.
Check the gas supply
valve, etc.
To correct the setting
Inspect for clogging of the heat exchanger,
abnormality of fan blades, etc.
Check for clogging of the heat exchanger,
deformation or clogging of fan blades, etc.
Adjust the manifold gas pressure to a correct value.
Check for improper connection of wir ing,
then replace the Gas Valve.
CN 10: between Red 4 - Blue 3
Check whether the manifold gas pressure can be adjusted.
Chec k the voltage of t
.
e
v
l
a
V
g
n
i
n
o
it
r
o
p
o
r
P
s
a
G
e
h
A
Check the carry over of burners.
Chec k the voltage of Gas Solenoid Valve-2
(SV2) and Gas Solenoid Valve-3 (SV3) .
During combustion, press the "Maxmum Manifold
Pressure Set Button" and check the voltage below.
(SV2 )
CN10 : Gr ay 7 - Blue 11
DC 1-16 V
(SV3 )
CN10 : Orange 6 - Blue 11
DC 1-16 V
During combustion, change the
hot water temperature and
water ow, and through the
peephole of the burner, check
that the number of burners
ignited switches normally.
Normal
Normal
Normal
Normal
Normal
Abnormal
Normal
Normal
Normal
Abnormal
Abnormal
Abnormal
Abnormal
Abnormal
Abnormal
Abnormal
Replace the Circuit Board set.
Replace the Circuit Board set.
Primary gas pressure list
902 Combustion abnormality
* When adjusting
the gas manifold
pressure, the
voltage change
within the range
DC 0.3 - 15V .
1
2
Pressure
Maximum
pressure
Standard
pressure
Minimum
pressure
Gas group
inch H
2
O
inch H
2
O
inch H
2
O
14.0
11.0
8.0
10.5
LP
NG
7.0
4.0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
BL
R
W
O
GY
BK
W
BL
W
BL
<CN10>
Display Window
Circuit Board
Dip Switch
Data
Display
1 2 3 4
R BL BL BL
<CN142>
14
13
12
11
10
9
8
7
6
5
4
3
2
1
12
11
10
9
8
7
6
5
4
3
2
1
3
2
1
W
Y
O
R
BK
V
G
O
Y
W
4
3
2
1
BL
BL
BL
R
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
2
3
4
5
6
7
4 3 2 1
BR Y BL R
R
O
Y
W
BL
R
W
O
GY
BK
W
BL
W
BL
2
1
BL/W
BK
BK 4 2
W
W
Fuse
3 1
R/R
G
3
2
1
BL
6
5
4
3
2
1
BK
R
W
W
3
2
1
R
BL
G
BL
W
R
Y
BK
BK
W
W
BK
W
<CN63>
<CN135>
<CN78>
<CN59>
<CN142>
<CN104>
<CN27>
<CN92>
<CN101>
<CN10>
<CN75>
<CN102>
<CN89A>
<CN89B>
<CN42>
Main
Circuit
Board
Po wer
Circuit
Board
Circuit Board
1 2 3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
BL
R
W
O
GY
BK
W
BL
W
BL
<CN10>
Display Window
Circuit Board
Dip Switch
Data
Display
1 2 3 4
R BL BL BL
<CN142>
14
13
12
11
10
9
8
7
6
5
4
3
2
1
12
11
10
9
8
7
6
5
4
3
2
1
3
2
1
W
Y
O
R
BK
V
G
O
Y
W
4
3
2
1
BL
BL
BL
R
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
1
2
3
4
5
6
7
4 3 2 1
BR Y BL R
R
O
Y
W
BL
R
W
O
GY
BK
W
BL
W
BL
2
1
BL/W
BK
BK 4 2
W
W
Fuse
3 1
R/R
G
3
2
1
BL
6
5
4
3
2
1
BK
R
W
W
3
2
1
R
BL
G
BL
W
R
Y
BK
BK
W
W
BK
W
<CN63>
<CN135>
<CN78>
<CN59>
<CN142>
<CN104>
<CN27>
<CN92>
<CN101>
<CN10>
<CN75>
<CN102>
<CN89A>
<CN89B>
<CN42>
Main
Circuit
Board
Po wer
Circuit
Board
Circuit Board
1 2 3
Check for the or
fold
Plat e, then replace the Manifold Plate that
does not open.
* Check the
y
b
e
r
u
s
s
e
r
p
y
r
a
m
ir
p
pressing
e
h
t
h
t
o
b
g
n
i
d
l
o
h
d
n
a
a
e
r
u
s
s
e
r
P
d
l
o
fi
n
a
M
m
u
m
i
x
a
M
nd Minimun Manifold Pressure Set Button.
“Output/FF+FB No . 50%”
(Maintenance #52 / Maintenance #51 50%)
<Condition of occurrence for error code 902>
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.)
* It is not necessary to replace the
Display Window Circuit Board.
* It is not necessary to replace the
Display Window Circuit Board.
Summary of Contents for NRC661-DV
Page 17: ...NR501 OD NR662 OD Thermistor Cold Water Thermistor Hot Water Gas Proportioning Valve 17...
Page 19: ...19 5 Operation Flow Chart Water heating Shutdown procedure Ignition operation NR501 OD...
Page 20: ...Water heating Shutdown procedure Ignition operation 20 NR662 OD...
Page 71: ...located 71...