Comfort-Aire HMB**V*1E SERIES - Manual (Page 13)

13
• For maximum capacity and energy efficiency, select an
airflow at or near the top of the range for that nominal
capacity. See Table 7 (page 19).
• 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 Humidistat and Delay Setting sections.
• 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 7 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.
Dehumidification Options
(HMB**X*1E, & HMB**V*1E Series Only)
Both motor control boards (Figures 13 & 14, page 24)
have a DHUM connection that allows the system to
increase the amount of humidity that is removed from
the circulating air. This is accomplished by reducing the
CFM and allowing the cooling coil to become colder. This
will only occur when there is a call for cooling. There are
many ways that this can be electrically wired.
1. If the room thermostat incorporates a humidity sensor
and DHUM output, connect the DHUM on the thermostat
to the DHUM terminal on the motor control board.
2. If using a separate humidistat, connect the DHUM & R
terminals on the humidistat to the DHUM & R terminals
on the motor control board of the air handler. In this
option, the
DHUM output of the humidistat must be set
to be normally open and closed when there is a call for
humidification. See Figure 7.
3. If a humidistat is not available, it is an acceptable option
to connect the R & DHUM terminals on the motor
control board together with a field supplied wire. This
option causes the blower to run at a reduced CFM for
10 minutes after a call for cooling.
NOTE: If outdoor unit
is a heat pump, connect the O terminal to DHUM.
DHUM
R R
DHUM
HUMIDISTAT
MOTOR
CONTROL BOARD
Figure 7. DHUM Wiring Configuration
UNIT MAINTENANCE
Proper maintenance is most important to achieve the best
performance from an air handler. Some of the components
and their locations are shown in Figure 9 (page 16). 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 air handler.
• 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.
• To achieve the best performance and minimize equipment
failure, it is recommended that a yearly maintenance
checkup be performed. At a minimum, this check should
include the following items:
Air Filter(s)
WARNING:
Never operate the air handler without a filter in
place. Dust and lint in the return air can build
up on internal components, resulting in loss of
efficiency, equipment damage, and possible fire.
Inspect and replace the air filter at the beginning of heating
and cooling season. It is recommended that the filter
be cleaned or replaced monthly. Newly built or recently
renovated homes may require more frequent changing
until the construction dust has minimized. Filters designed
to remove smaller particles such as pollen, may require
additional maintenance.
Blower Compartment
Dirt and lint can create excessive loads on the motor
resulting in higher than normal operating temperatures
and shortened service life. It is recommended that the
blower compartment be cleaned of dirt or lint that may
have accumulated in the compartment or on the blower
and motor as part of the annual inspection.