Specifications
COOLING SYSTEM
The cooling section is a complete factory package utilizing an
air-cooled condenser. The system is factory-charged with
Refrigerant-22.
The compressors are hermetically sealed, internally sprung
and base-mounted on spring isolators.
The compressors also have inherent (internal) protection. If
there is an abnormal temperature rise in a compressor, the
protector will open to shut down the compressor.
PRELIMINARY OPERATION COOLING
After installation has been completed, energize the crankcase
heaters for at least four hours before operating unit. After this
initial warm-up, the compressors should be given three false
starts (energized just long enough to make a few revolutions)
with 5-7 minutes delay between each start before being put into
full time service.
NOTE: Prior to each cooling season, the crankcase heaters
must be energized at least 10 hours before system is
put into operation.
COOLING SEQUENCE OF OPERATION
When the thermostat calls for “first-stage” cooling, the low
voltage control circuit from “R” to “G” and “Y1" (wiring
schematic) is completed to energize compressor #1,
condenser fan motor #1 and blower motor simultaneously.
When the thermostat calls for “2nd-stage” cooling, the low
voltage control circuit from “R” to “Y2" is completed to energize
compressor #2 and condenser fan motor #2.
After the thermostat is satisfied and opens, all components
likewise stop simultaneously.
SAFETY CONTROLS
Each refrigerant system is equipped with the following safety
controls:
1. A Suction Line Freezestat to protect aginst low evaporator
temperatures due to a low air flow or a low return air
temperature.
2. A High Pressure Cutout Switch to protect against excessive
discharge pressures due to a blocked condenser coil or a
condenser motor failure.
3. A Low Pressure Switch to protect against loss of refrigerant
charge.
If either one of the above safety controls opens, that individual
refrigerant system will bo locked out. The other refrigerant
system will continue in operation unless it too is effected by the
same fault. The lock out of either system can be reset by
opening the 24V circuit either at the room thermostat or at the
unit disconnect.
HEATING SEQUENCE OF OPERATION
SEQUENCE OF OPERATION WITH ELECTRIC HEAT
WITH POWER TO UNIT AND THERMOSTAT IN THE
HEATING MODE
Single-stage heating: (applies only to 9 KW heater, all other
heaters MUST use a two-stage thermostat:)
a) If the fan switch is in the "ON" position, the evaporator
blower motor contactor (3M) will be energized through
terminal G to provide continuous blower operation. If the
fan switch is in the "AUTO" position, the blower will operate
only when there is a call for heating by the thermostat.
b) Upon a call for heat by the thermostat, the heater contactor
(4M) will be energized.
c) The thermostat will cycle the electric heat to satisfy the
heating requirements of the conditioned space.
Two-stage heating: (applies to all heaters except 9 KW):
a) If the fan switch is in the "ON" position, the evaporator
blower motor contactor (3M) will be energized through
terminal G to provide continuous blower operation. If the
fan switch is in the "AUTO" position, the blower will operate
only when there is a call for heating by the thermostat.
b) Upon a call for first-stage heat by the thermostat, the heater
contactor (4M) will be energized.
If the second stage of heat is required, heater contactor
(5M) will be energized. Note that on the 54 KW 240V heater
that heater contactors (5M and 6M) will be energized.
c) The thermostat will cycle the electric heat to satisfy the
heating requirements of the conditioned space.
CONTINUOUS BLOWER - Continuous blower operation is
possible by closing the R to G circuit on the thermostat.
MODELS
BLOWER
RANGE
(RPM)
MOTOR*
ADJUSTABLE
MOTOR PULLEY
FIXED
BLOWER PULLEY
BELTS
HP
SERVICE
FACTOR
FRAME
SIZE
EFFICIENCY
(%)
PITCH
DIA.
(IN.)
BORE
(IN.)
PITCH
DIA.
(IN.)
BORE
(IN.)
PITCH
LENGTH
(IN.)
DESIG-
NATION
QTY
DCE090
975-1220
1-1/2
2
1.20 56 82.0 3.4 - 4.4 7/8 6.2 1 50.3 A49 1
DCE102
2
3
1.20 56 82.0 3.4 - 4.4 7/8 6.2 1 50.3 A49 1
DCE120 860-1090
2
3
1.20 56 82.0 3.4 - 4.4 7/8 7.0 1 57.3 A56 1
DCE150
860-1090 3 1.20 56 82.0 3.4 - 4.4 7/8 7.0 1 57.3 A56 1
960 - 1140 5 1.15 184 82.0 4.9 - 5.9 1-1/8 8.9 1 62.8
BX61
(Notched)
1
* All motors are 1750 RPM, have solid bases and are inherently protected. These motors can be selected to operate into their service factor because they are located in the moving air,
upstream of any heating device.
TABLE 7 - BLOWER MOTOR AND DRIVE DATA
OPERATION
530.18-N9Y
Unitary Products Group 13