Copeland Scroll Digital Compressor Controller
This compressor controller modulates the Copeland Scroll Digital compressor based on an input from the OEM’s system controller. The input signal from the system controller must vary between 0 and 5 VDC. The compressor controller then takes this input and determines how long the compressor should be unloaded over a 20 second period to provide the needed capacity. For example, the compressor controller interprets a 1.4 VDC input signal as a 10% capacity demand and sends a 2 second “ON” signal to the compressor and a 18 second “OFF” signal to match compressor capacity to demand. The compressor controller reads the input every 20 seconds and modulates the compressor accordingly.
Utilizing this compressor controller with the Copeland Scroll Digital compressor provides three sources of value.
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Fast Implementation
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By using the Copeland Scroll Digital compressor controller, no complicated system controllers are needed to enjoy the benefits of compressor modulation. Inverter-driven systems typically require special controllers to manage the inverter, the extra solenoid valves, and the complicated oil management systems. The Copeland Scroll Digital compressor controller can be installed inside the outdoor unit cabinet and easily wired into the system.
For contractors, the Copeland Scroll Digital compressor controller makes retrofitting existing systems with the Copeland Scroll Digital compressor relatively easy. With the necessary electronics contained within the controller, Copeland Scroll Digital can be easily used to upgrade existing systems, providing better temperature control and improved energy efficiency.
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Diagnostic Capability Reduces Downtime
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This controller not only modulates the Digital compressor, but it also detects common system problems and flashes an “Alert” LED to direct repair technicians to the root cause. Faults detected by this controller include:
| Alert Code |
Alert LED |
System Condition |
Explanation |
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2
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Blinks 2 times
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High Discharge Temp
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Discharge temperature is dangerously high |
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3
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Blinks 3 times |
Compressor Protector Trip |
Compressor motor protector has been tripped |
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4
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Blinks 4 times |
Locked Rotor |
Locked rotor current is detected |
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5
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Blinks 5 times |
Demand Signal Loss |
Compressor controller not receiveing demand signal |
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6
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Blinks 6 times |
Discharge Thermistor Fault |
Discharge thermistor is loose or faulty |
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8
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Blinks 8 times |
Compressor Contractor Fault |
Welded contractor - contractor is engaged when it should disengaged |
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9
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Blinks 9 times |
Low Voltage |
Voltage to controller is below minimum threshold |
The controller detects these problems by monitoring the compressor, the discharge gas temperature, and power level to the compressor. This increases repair technician accuracy, reduces troubleshooting time, and reduces the frequency of “No Defect” compressor replacements.
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Compressor Protection Capability
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Once any of the above system faults is detected, the Copeland Scroll Digital compressor controller takes action to prevent compressor damage. For example, if consecutive high discharge temperature conditions are detected, the compressor is taken offline until the problem is fixed. The controller deactivates the compressor when a locked rotor condition is recognized, preventing it from overheating. If the discharge thermistor becomes loose or defective, the controller constrains compressor maximum output to 50% so that heating or cooling is supplied while reducing the risk of overheating.
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