Allied EL120XP Informações sobre a unidade - Página 6
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Imprimir páginaWARNING
Electrostatic discharge can affect
electronic components. Take care
during unit installation and service to
protect the unit's electronic controls.
ELECTROSTATIC
Precautions will help to avoid control
DISCHARGE
exposure to electrostatic discharge
(ESD)
by putting the unit, the control and the
Precautions and
technician at the same electrostatic
Procedures
potential. Touch hand and all tools
on an unpainted unit surface before
performing any service procedure to
neutralize electrostatic charge.
I-UNIT COMPONENTS
The heat pump components are shown in figures on page 5.
A-Control Box Components
The heat pump control box components are shown in fig-
ure 1.
CONTROL PANEL
FIGURE 1
1 - Transformer T1
All models use a single line voltage to 24VAC transformer
mounted in the control box. Transformer T1 sup-plies pow-
er to control circuits in the unit. The transformer is rated at
90VA and is protected by a 6.0 amp circuit breaker (CB8).
CB8 is internal to the transformer. The 208/230 (Y) voltage
transformers use two primary voltage taps as shown in
figure 2, while 460 (G) and 575 (J) voltage transformers
use a single primary voltage tap.
208/230V TRANSFORMER
BLUE
SECONDARY
ORANGE
FIGURE 2
(CMC1)
RELAY (K8)
RELAY (K67)
RELAY (K10)
YELLOW
208 VOLTS
RED
230 VOLTS
PRIMARY
BLACK
NOTE – 208 volt units are field wired with the red wire
connected to control transformer. 230 volt units are factory
wired with the orange wire connected to control transform-
er primary.
2 - Condenser Fan Capacitors C1 and C2
All units use single-phase condenser fan motors. Motors
are equipped with a fan run capacitor to maximize motor
efficiency. Condenser fan capacitors C1 and C2 assist in
the start up of condenser fan motors B4 and B5. Capacitor
ratings are on condenser fan motor nameplates.
3 - Compressor Contactor K1 (all units)
All compressor contactors are three-pole-double break
contactors with a 24V coil. K1 energizes compressor B1
in all units.
4 - Transfer Relay K8
Transfer relay K8 ensures that the compressor will oper-
ate during all modes of operation by completing the Y1
circuit to the CMC1 defrost control board. When there is
a demand for cooling, the N.C. K8-2 contacts complete
the Y1 circuit to the CMC1 defrost board. When there is
a demand for heating, K8 relay coil energizes, using K8-2
N.O. contacts to complete the Y1 circuit to the CMC1 de-
frost control board and the K8-3 N.O. contacts to energize
the K67 relay.
5 - Terminal Strip TB14 (all units)
TB14 terminal strip distributes 24V power from the ther-
mostat to control box components.
6 - Defrost System
The defrost system includes a defrost thermostat and a
defrost control.
DEFROST THERMOSTAT S6 (ALL), S9 (120 ONLY)
The defrost thermostat is located on the liquid line between
the check/expansion valve and the distributor. When the
defrost thermostat switch senses coil temperature at set
point or lower (072/090 - 35°F ± 4°F; 120 - 42°F ± 6°F),
its contacts close and send a signal to the defrost control
board to start the defrost timing. It also terminates defrost
when the liquid line warms up to its set point (072/090 -
60°F ± 5°F; 120 - 70°F ± 5°F) and its contacts open.
DEFROST CONTROL BOARD CMC1
The defrost control board includes the combined functions
of a time/temperature defrost control, defrost relay, time
delay, diagnostic LEDs, and a terminal strip for field wiring
connections.
The control provides automatic switching from normal heat-
ing operation to defrost mode and back. During compressor
cycle (defrost thermostat is closed, calling for defrost, the
control accumulates compressor run times at 30, 60, or 90
minute field adjustable intervals. If the defrost thermostat
is closed when the selected compressor run time interval
ends, the defrost relay is energized and defrost begins.
DEFROST CONTROL TIMING PINS
Each timing pin selection provides a different accumulat-
ed compressor run time period for one defrost cycle. This
time period must occur before a defrost cycle is initiat-
ed. The defrost interval can be adjusted (T1–30, T2–60,
T3–90). The maximum defrost period is 14 minutes and
cannot be adjusted.
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