Lennox KHA SERIES, Руководство пользователя

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Page 26
de−energizes the compressor. When the compressor is de−
energized the cooling demand is handled by the economiz-
er. The switch automatically resets when outdoor tempera-
ture rises to 50° F (10° C).
8−Filter Drier (all units)
KHA units have a filter drier located in the liquid line of the re-
frigerant circuit at the exit of the condenser coil (outdoor coil
in KHA units). The drier removes contaminants and moisture
from the system. Replacement must be suitable for R−410A
refrigerant.
9−Crankcase Heater HR1 & Thermostat S40
All units have a crankcase heater. HR1 prevents migration
of liquid refrigeration into the compressor and ensures
proper compressor lubrication.
S40 is a N.C. thermostat located on the discharge line
which opens when discharge line temperature rises above
94°F (34°C). When S40 opens the crankcase heater is de−
energized. The thermostat closes when discharge line
temperature drops below 74°F (23°C) energizing the
crankcase heater.
C−Blower Compartment
KHA036 and 048 units are equipped with either direct drive
or belt drive blowers. KHA024S and 030S units are
equipped with direct drive blowers only and KHA060S units
are available with belt drive blowers only. See unit name-
plate for blower type. The blower compartment in all
KHA036/060 units is located between the evaporator coil and
the compressor compartment.
1−Blower Wheels
All belt drive units use 10" x 10" (254 mm x 254 mm) blower
wheels. The KHA024, 030, 036 and 048 direct drive units use
10" x 10" (254 mm x 254 mm) blower wheels also.
2−Indoor Blower Motor Capacitor C4
All single phase blower motors are PSC and requires a run
capacitor. Ratings may vary from each motor. See motor
nameplate for capacitor ratings.
3−Indoor Blower Motor B3
All direct drive units use single phase PSC motors. Belt
drive units use single or three phase motors (same as sup-
ply voltage). CFM adjustments on belt drive units are made
by adjusting the motor pulley (sheave). CFM adjustments
on direct drive units are made by changing speed taps. Belt
drive motors are equipped with sealed ball bearings. Direct
drive motors are equipped with sleeve bearings. Units may
be equipped with motors manufactured by various
manufacturers, therefore electrical FLA and LRA specifica-
tions will vary. See unit rating plate for information specific
to your unit.
OPERATION / ADJUSTMENT
IMPORTANT
Three phase scroll compressors must be phased se-
quentially for correct compressor and blower rota-
tion. Follow COOLING START−UP" section of instal-
lation instructions to ensure proper compressor and
blower operation.
A−Blower Operation
Initiate blower demand at thermostat according to instruc-
tions provided with thermostat. Unit will cycle on thermostat
demand. The following steps apply to applications using a
typical electro−mechanical thermostat.
1− Blower operation is manually set at the thermostat sub-
base fan switch. With fan switch in ON position, blow-
ers will operate continuously.
2− With fan switch in AUTO position, the blowers will cycle
with demand. Blowers and entire unit will be off when
system switch is in
OFF position.
B−Determining Unit CFM − Direct Drive Blowers
1− The following measurements must be made with air fil-
ters in place and no cooling demand.
2− With all access panels in place, measure static pres-
sure external to unit (from supply to return). Add any
additional air resistance for options and accessories
shown in air resistance table on Page 13.
3− Use figure 6 to determine the factory set blower speed.
BLOWER SPEED FACTORY SETTINGS
FIGURE 6
1
2
3
4
Com
Hi
Med
Low*
1
2
3
4
Com
Hi
Med *
Low
*Factory Setting
036 Units
024, 030,
048 Units
4− Use the blower tables starting on Page 7, mea-
sured static pressure and the factory−set blower
speed to determine CFM. If CFM is lower than the de-
sign specified CFM, move the lead from speed tap 3
or 4 to speed tap 2. See figure 7.
Note − Speed tap 3 can be used on 036 units if speed tap 2
delivers more CFM than required by design specification.
For 460/575V units, remove the isolation lead from speed
tap 2 before moving the wire to speed tap 2. Tape the ex-
posed end of the isolation lead and secure away from other
components. See figure 7.