Fans
Blower wheels and fan housing should be checked for
dirt build-up. If they appear dirty, it may be necessary to
remove the blower assembly and then vacuum the dust
out through the fan mouth. See figures 3 and 4 for instruc-
tions on removing the blower assembly.
System Operation Check
Verification of all control modes should be checked to
ensure proper operation. Refer to the Controls Section,
Sequence of Operation.
Testing and Replacement of the Damper Actuator
Check damper operation by switching between LOW -
COM or HIGH - COM on the dry contact terminal or by
switching through the modes on the optional remote wall
control. If the damper does not respond in one or both
directions, check all connections.
700 cfm ONLY:
Check for 24 volt output between the
White/Red and the White/Orange wires at the damper
motor. If 24 volts can be measured at the damper motor,
the problem is either in the connections, the frost control
relay or the main circuit board.
600/1
150
cfm ONLY:
(
CAUTION:
120 VAC) With the unit
powered but off, check for 120 volt output across the
white/black wires. If 120 volt can be measured at the
motor, replace the motor. If 120 volt cannot be measured
at the motor, check for 120 volts across pins J1-9 and
J1-1 at the printed circuit board.
Main Circuit Board Replacement
The main circuit board must be replaced if an electronic
problem arises. For example, the unit suddenly stops, the
unit stays in frost control mode all the time or if control
functions are not working properly.
Ensure that power is reaching the board. Test the
blower motors and damper actuators for operation when
directly connected to the appropriate power voltage. If the
motor and damper actuators function normally, replace
the main circuit board.
Motor and Blower Removal and Installation
Disconnect power from the unit. To determine if the fan
motor is burned out, disconnect the four-wire service con-
nector between the motor and cabinet. Connect the motor
directly to a 120 volt power source with an electrical cable
as follows:
If the motor functions normally, there is a problem with
the wiring connections or the main circuit board. Check all
wiring and replace main circuit board if necessary.
If the blower does not run, it must be replaced. To
replace the motor, remove the flat plate heat exchanger
from the unit. Disconnect the four-wire service connector
from the unit. Remove the fasteners holding the motor
assembly in place. Lift the assembly up and out, using
one hand under the motor and one hand to steady it.
Remove the assembly carefully from the unit to avoid
damage to the insulation, shelf, etc. Install the repaired
motor assembly by following these instructions in reverse.
WARNING
Hot water and strong cleaning agents could damage
the polypropylene heat exchanger. Ensure the heat
exchanger is returned to the unit in the correct orienta-
tion. Use the sticker as a guide.
Figure 4: Blower Assembly Removal
700 cfm
RED + WHITE
Low speed
BLUE + WHITE
Medium speed
BLACK + WHITE
High speed
Capacitor
Locking Plate
Remove these
two screws
Service
Connector
Thumbscrew
Figure 3: Blower Assembly Removal
600 cfm and 1
15
0 cfm
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