Symptom
Diagnostic Test
Resolution
connection, check
for 115 VAC between
pins 4 and 7 (blue
and brown).
With power off, check for
proper seating of the
ribbon cable between
the power board and the
touch control.
Blower
motor runs
only at high
speed.
Power board fault.
Replace the power
board.
Hood lights
do not
work.
One LED is out in the
LED light assembly.
Replace the LED light
assembly.
Remove the connector
from the secondary side
of the transformer, and
check for 12 VDC
between the pins on the
transformer.
Refer to "
on page
17." If there is no
voltage, replace the
transformer.
Unplug the two-pin
connector behind the
light support, and check
for 12 VDC.
Refer to "
on page 18." If
necessary, replace the
harness to the hood
body.
Ohm out the LED light
assembly connector.
Verify there is no short.
Replace the LED light
assemblies.
Remove the connector
LUX1 from the power
board, and check for 115
VAC from pin 1 to pin 2.
If the blower motor is
working, replace the
power board.
Remove the connector
from the transformer's
primary side, and check
for 115 VAC between the
orange wires.
Replace or repair the
harness from the power
board to the transformer.
Blower
motor does
not run at
any speed.
Note: Do these checks
before checking the
internal blower motor or
the external/inline blower
motor.
Check the voltage at the
wiring box:
▪
L1 to ground = 115
VAC
▪
N to ground = 0 VAC
▪
L1 to N = 115 VAC
If the lights are working,
this is likely a short or
loose connection. Refer
to "
on
page 17."
Check the voltage on the
blower side of the 9-pin
connector:
▪
L1 to ground = 115
VAC
▪
N to ground = 0 VAC
Refer to "
on page
18." If necessary,
replace or repair the
electrical connector or
wires.
Symptom
Diagnostic Test
Resolution
▪
L1 to N = 115 VAC
Check the voltage at the
three-pin connector in
the network filter box.
▪
Pin 1 to pin 2 = 115
VAC
▪
Pin 2 to pin 3 = 0
VAC
▪
Pin 1 to pin 3 = 115
VAC
Replace or repair the
electrical connector or
wires.
Check the voltage at the
power board: Pin 1 to
pin 2 = 115 VAC
Replace or repair the
connector from the
network filter box to the
power board.
Check for 115 VAC at
the three-pin connector
in the network filter box.
Replace or repair the
connector from the
power board to the
network filter box.
Problem
with
internal
blower
motor.
Note: Do
the “Blower
motor does
not run at
any speed”
checks
before
these
checks.
The internal
blower will
need to be
removed.
With the internal blower
connected and power
applied, check pin 4 to
pin 5 for 115 VAC on the
hood side of the
connector.
Replace the blower
motor harness.
Disconnect the blower.
On the motor side of the
connector, ohm out:
▪
Pin 4 to pin 5
▪
Pin 4 to motor case
▪
Pin 5 to motor case
Refer to "
18." If reading open pin
4 to pin 5, or continuity
pin 4 or pin 5 to motor
case, verify it is not the
blower motor harness,
then replace the blower
motor.
Problem
with
external/
inline
blower
motor.
Note: Do
the “Blower
motor does
not run at
any speed”
checks
before
these
checks if
needed.
On the motor side of the
terminal block,
disconnect the external/
inline blower motor
wires. Ohm out between
the wires. Measure the
resistance between each
wire and ground.
If reading open between
blower wires, or
continuity from either
blower wire to ground,
verify the wiring between
the terminal block and
blower motor is good. If
the wiring is good,
replace the external/
inline blower.
Blower
motor runs,
but not at
all four
speeds.
Possible failure of the
triac on the power board,
or a touch control failure.
At this time, there is no
Replace the power board
or touch control.
Ceiling-Mounted Hood
Ceiling-Mounted Hood Troubleshooting Table (continued)
service.subzero.com
828149 REV. A
15