OVERVIEW
The SYCAP is a single stage cool, two stage heat Heat Pump Capacity
Controller. It works in conjunction with the System 1000 SYHPA
Switching Center only. Its function is to control the heat pump coil
leaving air temperature within a set operating range.
When the heat pump is running, the SYCAP keeps the heat pump coil leaving
air temperature within operating range by turning the heat pump
compressor off for a minimum of four minutes if the air temperature gets
too cold in cool mode or too hot in heat mode. The SYCAP will also turn
on the heat pump auxiliary heat if the coil leaving air temperature is not
hot enough in heat mode. The compressor is kept off for a minimum of
four minutes to prevent short cycling.
OPERATION
The SYCAP has two relays (K1 and K2) and two corresponding status
lights (DL1- red and DL2- green). Relay K1 is a normally closed relay.
When energized, it breaks the connection between Y1 Y1 which disables
the heat pump compressor. Relay K2 is a normally open relay. When
energized, it makes the connection between W2 W2 which enables the
heat pump auxiliary heat.
There are three adjustable setpoints on the SYCAP: Heat Cut-out, Cool
Cut-out, and Auxiliary Heat Cut-in. The Heat Cut-out Setpoint is the
maximum allowable leaving air temperature in heat mode. If the air
temperature rises above this setpoint in heat mode, the compressor is
disabled for a minimum of four minutes. The Cool Cut-out setpoint is the
minimum allowable leaving air temperature in cool mode. If the air
temperature drops below this setpoint in cool mode, the compressor is
disabled for a minimum of four minutes. The Auxiliary Heat Cut-in
temperature is the minimum allowable leaving air temperature in heat
mode. Four minutes after the heat pump compressor has been turned
on, if the coil air temperature cannot rise above this setpoint, the auxiliary
heat is enabled. The auxiliary heat is disabled when the air temperature
rises nine degrees above the Auxiliary Heat Cut-in setpoint.
The SYCAP knows which mode of operation it is in by monitoring the W2
signal from the SYHPA Switching Center. If W2 is energized, it knows the
SYHPA is making a heat call.
The following is a detailed operation description of each mode.
IN RANGE, HEAT MODE
– If the SYHPA Switching Center is making
a heat call and the leaving air temperature is below the Heat Cut-out
setpoint and above the Auxiliary Heat Cut-in, relays K1 and K2 are
de-energized, red light DL1 is off and green light DL2 is off. The leaving
air temperature is displayed on the digital display.
COOL CUT-OUT –
If the SYHPA is making a cool call and the leaving
air temperature drops below the Cool-Cut-out setpoint, the connection
between Y1 Y1 breaks, red light DL1 turns on, and the Heat Pump
compressor is disabled. Every four minutes after Y1 is broken, the
leaving air temperature is checked. If the temperature rises above the
cool cut-out setpoint, Y1 Y1 is made, red light DL1 turns off and the
compressor is re-enabled.
HEAT CUT-OUT
– If the SYHPA is making a heat call and the leaving air
temperature rises above the Heat Cut-out setpoint, the connection between
Y2 Y2 breaks, red light DL1 turns on, and the Heat Pump compressor is
disabled. Every four minutes after Y2 is broken, the leaving air temperature
is checked. If the temperature drops below the heat cut-out setpoint, Y2
Y2 is made, red light DL2 turns off and the compressor is re-enabled.
AUXILIARY HEAT CONTROL
– Four minutes after the SYHPA initiates
a heat call, the leaving air temperature is continuously checked. If the air
temperature does not rise above the Auxiliary Heat Cut-in setpoint, green
light DL2 turns on, the connection between W2 W2 is made, and the Heat
Pump Auxiliary heat is enabled. When the leaving air temperature rises
nine degrees above the auxiliary heat cut-in setpoint, green light DL2
turns off, W2 W2 is broken, and the auxiliary heat is disabled.
SYCAP Components
The SYCAP consist of the following:
A. Digital Display –
Three digit LED. Normally displays the coil
leaving air temperature of the heat pump. When “E” displayed,
indicates SYCAP is in Enable mode; refer to OPERATION section. When
the UP/DN buttons are pressed, the cutout setpoints are displayed.
Refer to the Setpoint Calibration section for reading and adjusting
the setpoints.
B. Microcontroller –
Brains of the SYCAP and where the program
resides. Occasionally, software upgrades may become available. If so,
the SYCAP software can be field upgraded by changing this micro-
controller.
C. Status Lights –
Red light DL1 is on when relay K1 is energized.
Green light DL2 is on when relay K2 is energized. See E.
D. Thermometer Calibrator –
Calibrates the leaving air temperature
thermometer. Turn clockwise to lower temperature. Turn counter-
clockwise to raise. Refer to CALIBRATION section for complete
calibration information.
E. Relays K1 and K2 –
SPST relays. Relay K1 is a normally closed
relay. When energized, it breaks contact between Y1 Y1. Relay K2 is
a normally open relay. When energized, makes contact between W2
W2 terminals.
F. Leaving Air Sensor (LAS) Terminals –
Leaving air temperature
sensor is connected to the SYCAP here. Red to + and white to –. The
sensor monitors the coil leaving air of the heat pump. If preferred,
the SYCAP can be mounted up to 500 feet from the sensor. See
INSTALLATION section for further information.
G. Heat Pump/Switching Center Interface Terminals –
Y1
controls the heat pump compressor. W2 controls the heat pump
auxiliary heat. One Y1 and W2 connect to the Switching Center, the
other Y1 and W2 connect to the heat pump. It does not matter which
W2/Y1 connects to the Switching Center and which connects to the
heat pump. See WIRING section for detailed wiring instructions.
CAPACITY CONTROLLERS - SYCAP
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