6
Communication and Status Function Lights
For Infinity Control Only, Green communications
(COMM)Light
Green LED (COMM Light)
A green LED (COMM light) on the outdoor board (see Fig. 6)
indicates successful communication with the other system
products. The green LED will remain OFF until communications is
established. Once a valid command is received, the green LED will
turn ON continuously. If no communication is received within 2
minutes, the LED will be turned OFF until the next valid
communication.
Amber Status Light
An amber colored STATUS light is used to display the operation
mode and fault codes as specified in the troubleshooting section.
See Table 5 for codes and definitions.
NOTE: Only one code will be displayed on the outdoor unit
control board (the most recent, with the highest priority).
Utility Interface with Infinity Control
The utility curtailment relay should be wired between R and Y2
connections on the control board for Infinity Communicating
Systems only (see Fig. 6). This input allows a power utility device
to interrupt compressor operation during peak load periods. When
the utility sends a signal to shut the system down, the User
Interface will display, “Curtailment Active”.
Compr e ssor Operation
The basic scroll design has been modified with the addition of an
internal unloading mechanism that opens a by-- pass port in the first
compression pocket, effectively reducing the displacement of the
scroll.
The opening and closing of the by-- pass port is controlled by an
internal electrically operated solenoid. The modulated scroll uses a
single step of unloading to go from full capacity to approximately
67% capacity. A single speed, high efficiency motor continues to
run while the scroll modulates between the two capacity steps.
Modulation is achieved by venting a portion of the gas in the first
suction pocket back to the low side of the compressor, thereby
reducing the ef fective displacement of the compressor. Full
capacity is achieved by blocking these vents, thus increasing the
displacement to 100%.
A DC solenoid in the compressor controlled by a rectified 24 volt
AC signal in the external solenoid plug moves the slider ring that
covers and uncovers these vents. The vent covers are arranged in
such a manner that the compressor operates at approximately 67%
capacity when the solenoid is not energized and 100% capacity
when the solenoid is energized. The loading and unloading of the
two step scroll is done “on the fly” without shutting off the motor
between steps.
NOTE: 67% compressor capacity translates to approximately
75% cooling capacity at the indoor coil. The compressor will
always start unloaded and stay unloaded for five seconds even
when the thermostat is calling for high--stage capacity.
Crankcase Heater Operation
The crankcase heater is energized during off cycle below 65_F
(18.33_C).
Outdoor Fan Motor Operation
The outdoor unit control energizes the outdoor fan any time the
compressor is operating except for low--ambient cooling operation.
The outdoor fan remains energized if a pressure switch or
compressor overload should open. Outdoor fan motor will
continue to operate for one minute after the compressor shuts off
when the outdoor ambient is greater than or equal to 100_F
(37.78_C) to allow for easier starting during next cooling cycle.
The outdoor fan motor is a PSC type. A fan relay on the control
board turns the fan off and on by opening and closing a high
voltage circuit to the motor. It does not change speeds between low
and high stage operation.
Time Delays
The unit time delays include:
S Five minute time delay to start cooling or heating operation
when there is a call from the thermostat or user interface. To
bypass this feature, momentarily short and release Forced
Defrost pins.
S Five minute compressor re-- cycle delay on return from a
brown--out condition.
S Two minute time delay to return to standby operation from last
valid communication (with Infinity only).
S One minute time delay of outdoor fan at termination of cooling
mode when outdoor ambient is greater than or equal to 100_F
(37.78_C).
S There is no delay between staging from low to high and from
high to low capacity. The compressor will change from low to
high and from high to low capacity “on the fly” to meet the
demand.
Infinity Controlled Low Ambient Cooling
This unit is capable of low ambient cooling down to 0_F
(--17.78_C) without a kit -- ONLY when using Infinity control. A
low ambient kit is not required, and the outdoor fan motor does not
need to be replaced for Infinity controlled low ambient operation.
The Infinity Control provides an automatic evaporator coil freeze
protection algorithm that eliminates the need for an evaporator
freeze thermostat. Low ambient cooling must be enabled in the
User Interface set up. Fan may not begin to cycle until about 40_F
(4.4_C) OAT. Fan will cycle based on coil and outdoor air
temperature.
Infinity controlled low ambient mode operates as follows:
— Fan is OFF when outdoor coil temp is less than outdoor
air temperature (+3_F / 1.67_C) or outdoor fan has been
ON for 30 minutes. (Fan is turned off to allow refrigerant
system to stabilize.)
— Fan is ON when outdoor coil temp is more than outdoor
air temperature (+ 25_F / 13.89_C) or outdoor coil temp
is more than 80_F (26.67_C) or if outdoor fan h as been
OFF for 30 minutes. (Fan is turned on to allow
refrigerant system to stabilize.)
— Low pressure switch is ignored for first 3 minutes during
low ambient start up. After 3 minutes, if LPS trips, then
outdoor fan motor is turned off for 10 minutes with the
compressor running. If LPS closes within 10 minutes,
then cooling continues with the outdoor fan cycling per
the coil temperature routine listed above for the
remainder of the cooling cycle. If the LPS does not close
within 10 minutes, then the normal LPS trip response
(shut down cooling operation and generate LPS trip
error) will occur.
24APA7
To Next Page
Loading...
