Nortek B64EM Series, Installation Instructions Manual

Page: 12 / 28

12
DISPLAY
CODE
CURRENT MODE
-
Standby is a Rotating Segment
Cooling Mode (Y input active)
Heating Mode (W input active)
Circulate Fan Mode (G input active)
Dehum Cooling Mode (DEHUM input active along with Y)
(one) A Motor Fault has Occurred (BMF active for more than
30 seconds)
(lower case t) Over Temperatures (The value of the TS input
has exceeded 80C all outputs are stopped.)
Lockout (Ten (10) or more Motor Faults or Over Temperature
events have occurred. All outputs are set to off for one hour.
Basic Cooling / Heat Pump Airflow for Variable & Fixed
Speed
The basic cooling/heat-pump airflow is controlled by setting
switches 5 - 8 on the motor control board (mounted on the
blower). All airflows for other modes of operation (except
electric heat) are determined by this basic setting. FAN ONLY
would deliver 50% of the selected cooling airflow. Table 8,
(page 18) lists the CFM airflow values recommended for
each nominal system capacity. To determine dip switch
settings, refer to Table 6, (page 16) for FSHE applications and
Table 9, (pages 19 and 20) for VSHE applications.
• When operating in the heat pump mode, a higher basic
airflow setting will increase the energy efficiency and
capacity but will also decrease the supply air temperature.
• For maximum capacity and energy efficiency, select an
airflow at or near the top of the range for that nominal
capacity. See Table 8, (page 18) .
• For maximum dehumidification, select an airflow near the
middle or bottom of the range for that nominal capacity.
Additional information on humidity control can be found
in the Dehumidication Options section on page 10 .
• For thermostats with a dehumidifier output, use a field
supplied wire to connect the thermostat’s dehumidifier
output to the terminal marked DHUM . The thermostat
should be set so that the DHUM output should be high
(energized) when dehumidification is needed. See also
Dehumidification Options section.
IMPORTANT! If coil icing is observed, the basic cooling/
heat-pump airflow selected may be too low. Verify the setting
selected is within the range shown in Table 8 (page 18) and
that the the system is properly charged. Please refer to the
instructions supplied with the outdoor unit. If icing continues
to occur, raise the selected airflow one or two steps.
NOTE: Variable speed air handlers with SEER ratings higher
than 15 are matched with a 2-stage cooling outdoor unit.
They are programmed to operate at 75% of the selected
airflow while the system is in the lo-cool mode and 100%
of the selected airflow while in hi-cool mode.
Units with an FSHE control scheme (B64EM) have a control
board that includes a 7 segment display to help the installer
identify what mode the air handler is running in as well
as troubleshooting if the unit is not functioning properly.
Table 2, contains a list of the codes that may appear on the
7 segment display. The display code will only show what
mode the air handler is currently in. There is not a history
of fault codes that have occurred in previous operation.
TROUBLESHOOTING
If the air handler fails to operate, check the following:
• Is the electric turned on?
• Is the thermostat operating properly?
• Are the blower compartment door(s) in place?
• Is the air handler disconnect closed?
• Has the circuit breaker tripped or the control board fuse
burned open?
• Are any manual reset switches open?
• Is the filter dirty or plugged?
• Is the LED on both control boards constantly ON? If not,
refer to Table 3 or Table 4 to determine fault condition.
UNIT MAINTENANCE
Proper maintenance is most important to achieve the best
performance from a air handler. Some of the components
and their locations are shown in Figure 9 (page 15) . If
any component of the air handler must be replaced, use
only factory authorized replacement parts specified in the
Replacement Parts List provided online.
WARNING:
ELECTRICAL SHOCK, FIRE OR
EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
• Before servicing, disconnect all electrical power
to the indoor blower.
• When servicing controls, label all wires prior
to disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
• These maintenance instructions are primarily intended
to assist qualified technicians experienced in the proper
maintenance and operation of this appliance.
• Always reinstall the doors on the air handler after servicing
or cleaning/changing the filters. Do not operate the air
handler without all doors and covers in place.
Table 2. FSHE Motor Control Board Display Codes
RED LED (AN2) DIAGNOSTIC
OFF Control Fault (No Power)
Flash Blower Fault
ON Normal Operation
Table 3. Air Handler Control Board Fault Conditions
DIAGNOSTIC FAULT CONDITIONS
FOR VARIABLE SPEED FURNACES
GREEN
LED
RED
LED
Control Fault (No Power) Off Off
Normal Operation On On
Motor Fault On Flash
Communications Fault Flash Flash
Table 4. VSHE Motor Control Board Display Codes