520 Indoor / 520 Outdoor Service Manual
Ver. 1.00
21
CONFIDENTIAL
10-4. Fan motor for exhaust
Unit Part #
#124
AOS Part #
319143-053
Checkpoint
G2
Function
To control exhaust temperature.
Failure events
1. Fan speed failure, causing abnormal sounds with or without combustion
during operation.
2. Unexpected activation caused by the connectors of the fan motor getting
wet.
3. Disconnects from the exhaust chamber.
Effects on the water
heater if fan motor for
exhaust fails
1. The water heater does not function properly
2. Unstable exhaust gas temperature
Error codes when the fan
motor fails
621 (520 Indoor only)
941 (520 Indoor only)
Diagnostic
1. Visual inspection: connection/breakage of wires or dust (causing electrical
shortage)
2. Voltage check: proper range of voltages shown below.
Color/Number of wires
Red-Blue
110 to 160 VDC (Input)
Yellow-Blue
13 to 17 VDC (Input)
Orange-Blue
2.0 to 6.5 VDC (Input)
White-Blue
Verify the fan motor speed for exhaust using the
Diagnostics Mode of the 520 Indoor computer board or the
9007603005 temperature remote controller. See Section
12-1 for details.
The fan motor for exhaust of the 520
Indoor has the “46” mark as shown
the picture to the right.
5 - 7 / 8 " ( 1 5 1 m m )
3
-
1
/
4
"
(
8
6
m
m
)
46
5
-
3
/
8
"
(
1
3
7
m
m
)
"4 6 " m a r k
O
p
e
n
i
n
g
1
-
3
/
4
"
(
4
6
m
m
)
