Exhaust Temperature Is Too High <(L)Whic56 Only; Combustion Abnormality (Appliance Is Stopped) - Noritz WHiC56 Service Manual

Error Code 94 Exhaust temperature is too high <(L)WHiC56 only>
Check the exhaust thermistor resistance.
Normal
CN63 : Between White 7 - White 2
Refer to the thermistor temperature
characteristics below.
When measuring the resistance,
disconnect the connector and
check the male side.
Exhaust Thermistor Temperature Characteristics
-20
487
Error Code 99

Combustion abnormality (Appliance is stopped)

Replace the appliance for the end of its service life.
Refer to the lower list to confirm the occurrence condition for error code 99.
(The appliance is reset by the electrical power disconnect and reconnect.)
<The occurrence condition for error code 90, 10, and 99>
①(L)WHiC56, (L)WHiCX56 ②(L)WHi49, (L)WHiX49
Equipment status
Fan speed
Output
correction
①103%, ②104% or more
(less than ①104%, ②106%
①104%, ②106%
①103%, ②104% or more
(less than ①104%, ②106%
①104%, ②106%
Target output x 50%
actual output
Abnormal
<CN63>
-10 0 10 20 30
276 162 98.3 61.5 39.5
Equipment
usage period
Less than 5 years
Less than 5 years
5 years or more
5 years or more
<The occurrence condition for error code 94>
The message is displayed if exhaust temperature is 60°C or more.
Circuit Board
<CN42>
W 4 1 BK
5 2 <CN101>
6 3
BL 6 1 R
R 7 2 BL
W 8 3 G
9 4 W
O 10 5 Y
1 W 1 BK
2
2 3 W
W
4
5 W
3 W
6 BL
7 BR
4
W
8 GY
9 BK
5 W
10
O
11
6
W
12 W
<CN10>
7
W
40
26.1
Check air inlet for blockage or obstruction.
Check exhaust for blockage or obstruction.
Check the Fan Motor is normal.
(ex. Clogging of fan blades, etc.)
Check for the Primary Heat Exchanger is normal.
(ex. The surface discolors black, clogging, etc.)
Error
Code
"90" is displayed as combustion abnormality (warning indicator).
"90"
Appliance will continue operation.
"90" Appliance is stopped.
"10" is displayed as warning of service life (warning indicator).
"10"
Appliance will continue operation but output is dropped.
"99" Appliance is stopped.
"90" Appliance is stopped.
- 43 -
<CN186>
1 R
MAIN
2 BK
3 W
CIRCUIT
4 G
5 BL
BOARD
6 BL
W 31 32
1
R 29 30
2
V 27 28 BK
<CN78>
O 25 26 G
W 23 24 BK
21 22
19 20 V
BL 17 18 G
O 15 16 O
1 W 13 14 BL
2 W 11 12
3 W 9 10 Y
4 W 7 8 R
1 BL
5 W Y 5 6 Y
2 BL
6 W R 3 4 BK
3 BL
7 W 1 2 W
<CN63> <CN38> <CN89>
Check for improper connection of wiring.
Replace the exhaust thermistor.
Equipment operation
BL
1 2 3
BK
<CN197>