21
Fig. 29 —
Air Vents
Direct Expansion (DX) Systems
NOTE: Operation of DX equipped fan coils at any fan speed other
than high fan speed is not approved and will void the manufactur
-
er's limited warranty.
Do not operate fan coils with a DX evaporator coil plus contigu
-
ous hydronic coil without use of a suitable glycol solution that is
approved for use by the manufacturer. Failure to follow this in
-
struction will void the manufacturer's limited warranty.
Should the evaporator freeze due to inadequate airflow for any
reason, damage may occur to adjacent water or steam coil tubing.
This type of issue is due to product misapplication and voids the
manufacturer's limited warranty.
Air Balance System
All ductwork must be complete and connected. All filters and
access doors and panels must be properly installed to establish
actual system operating conditions BEFORE beginning air
balancing operations.
Each individual unit and the attached ductwork is a unique system
with its own operating characteristics. For this reason, air balanc
-
ing is normally done by balance specialists who are familiar with
all procedures required to properly establish air distribution and
fan-system operating conditions. These procedures shall not be at
-
tempted by unqualified personnel.
After proper system operation is established, the actual unit air de
-
livery and the actual fan motor amperage draw for each unit
should be recorded in a convenient place for future reference.
Motor/Blower Assembly
Fan operation type is determined by the control components and
their method of wiring. This may vary from unit to unit. Refer to
the wiring diagram attached to each unit for individual operating
characteristics. See Tables 5-7 for motor performance and heater
availability.
All motors have permanently lubricated ball bearings. No field
lubrication is required.
Should the motor/blower assembly require service, it may be
removed from unit to facilitate operations such as motor or blower
wheel/housing replacement, etc.
Dirt and dust must not be allowed to accumulate on blower wheel
or housing. This can result in an unbalanced blower wheel condi
-
tion which will damage a blower wheel or motor. The wheel and
housing must be cleaned periodically using a vacuum cleaner and
a brush taking care not to dislodge factory balancing weights on
the blower wheel blades.
Electronically Commutated Motor (ECM)
All 42DH/DV units are equipped with Electronically Commutated
Motors (ECM) — constant speed brushless DC, which are easily
adjustable in the field for desired performance. Motors are
pre-programmed for constant speed mode. 1/2 HP and 1 HP
motors have integrated control module with overload and short
circuit protection. 1-1/2 HP and 3 HP motors have remote
mounted control module with overload and short circuit protec
-
tion. Control module is mounted in the cabinet interior.
Control Board Adjustment
Adjusting the low, medium and high potentiometer requires the
use of multi-meter capable of measuring 0-10 vdc. (See Fig. 30.)
Fig. 30 —
Motor Control Board
When the 42DH/DV unit is shipped from the factory with motor
control board (which has High, Med and Low airflow settings),
it is pre-programmed at the factory to “High” speed and delivers
the airflow and cooling/heating capacity specified at the time of
order, while Medium and Low speeds are set to defaults based
on High speed. Should airflow require adjustment after installa
-
tion, the control board settings for Low, Medium and High could
be adjusted by turning screws (as shown in Fig. 30) using a small
Phillips screwdriver. It will adjust the control voltage to the
motor. A clockwise rotation increases the voltage to the motor,
while counter clockwise rotation reduces it.
IMPORTANT: The air vent provided on the unit is not intended
to replace the main system air vents and may not release air
trapped in other parts of the system. Independently inspect the
entire system for potential air traps and vent those areas as re
-
quired. In addition, some systems may require repeated venting
over a period of time to properly eliminate air from the system.
WARNING
Failure to follow this warning could result in personal injury or
death. Please wait 5 minutes after disconnecting power before
opening the motor.
Manual Air Vent
Automatic Air Vent
CAUTION
Only trained and qualified individuals should attempt to adjust
or service components on any energized electrical equipment.
Failure to follow established safety rules and guidelines could
result in serious injury or death.
IMPORTANT: On 42DH/DV units with electric heat the factory
default setting for low airflow prevents nuisance tripping of the
electric heat protection circuit. Turning the low speed screw
counter clockwise can cause interruptions in the heating perfor
-
mance of the unit due to the activation of this protective circuit.
CAUTION
Turning the voltage up past the setting for high speed may in
-
troduce the risk of condensate blow off which may result in
damage to the unit.
L2
LOW
MED
HIGH
VR1
VR2
VR3
K1
K2
K3
LOW
MED
HIGH
COM
C1
C2
C3
CR1
L1
POTS
