Johnson Controls DSH024C Series, Установка, эксплуатация и обслуживание

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34
FORM 145.32-IOM5
ISSUE DATE: 04/08/2019
SECTION 1 – INSTALLATION
BLOWER SPEED ADJUSTMENT
Adjust the blower speed to increase or decrease the unit
CFM for both non-VFD and factory installed VFD. The
RPM of the supply air (SA) and condenser air blowers
depends on the required CFM and the static resistances
of both the supply/discharge and the return/intake duct
systems. For units with VFD, perform the required static
and drive setup at the 100% fan speed condition.
Perform an air balance after installation to verify the
airflow and static. This may require adjustments to
the drive (refer to Variable Frequency Drive Installa-
tion and Operation Instructions ( Form 145.13-NO1 ).
Only operate the unit in the regions defined by the fan
tables. The units can be ordered with oversized motors
or drive kits for high static requirements.
Units with oversized motors or oversized
drive kits are designed to operate in the
shaded region of the fan table. Otherwise,
the motor amp draw exceeds the overload
setting resulting in overload trips and pos-
sible damage to unit. Refer to fan tables
for recommended operating range of stan-
dard and oversized motors and drive kits.
Adjusting the Blower Speed
Determine the RPM for the blowers from the tables in
Fan Performance on page <?> . To adjust the blower
speed, take the following steps:
1. Loosen the belt tension by moving the motor to-
wards the blower shaft via the adjustable mount-
ing.
2. Loosen the setscrew in the adjustable motor pul-
ley flange.
3. Remove the external key on pulleys that are 4
inches diameter or larger.
4. Open or close the pulley an appropriate number
of turns.
The blower speed increases when the move-
able flange is adjusted towards the fixed flange
(closed). The blower speed decreases when the
moveable flange is adjusted away from the fixed
flange (opened).
Pulleys are adjustable only in half-turn incre-
ments. For 4L and A belts, do not open the pulley
more than five full turns. For B belts, do not open
the pulley more than six full turns.
5. Replace the external key and tighten the adjust-
ment setscrew. Proper torque is 110–130 in-lbs.
6. Install the drive belt and adjust the motor mount to
the tension belt (for further information, see Sec-
tion 3 – Maintenance and Service
).
LOW AMBIENT DAMPER
If the unit must operate at an outdoor ambient below
50.0°F, install the optional low ambient damper kit. This
kit maintains an acceptable condensing pressure. Install
the damper directly onto the intake duct connection
(see Figure 17 on page 35 ). Determine the damper
position by the refrigerant pressure. Depending on a
proportional pressure control module's output signal,
a direct-coupled electric damper actuator motor drives
the damper open or closed.
A pressure transducer senses the high-side refrigerant
pressure through a service access port. The port is locat-
ed on the liquid refrigerant line leaving the condenser.
The pressure controller, complete with terminal con-
nection blocks for wiring, attaches to a field-installed
mounting bracket.
The kit includes an appropriate mounting hardware
for the pressure control module and the damper actua-
tor motor. There is also a routing hole in the condenser
corner panel, near the actuator mounting location, for
installation of the plenum-rated cable between the motor
and the control module.
On dual compressor units, the actuator
MUST be connected to the #1 circuit liq-
uid line fitting. Connection to the second
stage refrigerant circuit will result in
system malfunction.
For detailed installation instructions, refer to the sup-
plementary Low Ambient Damper Kit Installation and
Operation Instructions (
Form 145.10-IOM4
).