LG AR-DR12-05A Installation And Operation Manual page 125

• Low Condenser Pressure: If the liquid pressure, or the discharge pressure minus an offset (if liquid pressure is not available), falls below
the low condenser set-point for the duration of the compressor protection delay, a low condenser pressure alarm activates. This alarm
remains active after the alarm condition clears for the duration of the envelope alarm lockout delay or until the alarm is manually reset.
• Abnormal Pressure: If the discharge pressure minus the suction pressure is less than 30 psi for 240 seconds, an abnormal pressure alarm
activates. This alarm remains active after the alarm condition clears for the duration of the envelope alarm lockout delay or until the alarm is
manually reset.
Units With Electronic Expansion Valves: When an inverter scroll compressor is installed with an electronic expansion valve, the following
compressor envelope logic applies:
• Compressor Envelope Zones: As the compressor operation
approaches a zone other than the normal operation (Zone 1), the
controller modulates the inverter compressor's speed according to
the compressor control algorithm to prevent the compressor from
leaving Zone 1.
If the compressor is outside Zone 1 for a period, an alarm activates
corresponding to the following zones:
• Zone 2: High Pressure Ratio
• Zone 3: High Discharge Pressure
• Zone 4: High Motor Current
• Zone 5: High Suction Pressure
• Zone 6: Low Pressure Ratio
• Zone 7: Low Delta Ratio
• Zone 8: Low Discharge Pressure
• Zone 9: Low Suction Pressure
Water Source Heat Pump
Water Valve: At a call for a compressor, the following occurs:
• The water source heat pump water valve for that circuit opens to 100%; and
• Notifies the BMS to start the pump via:
• Hardwired output by closing the contact on the board; and
• BMS-communicated point by enabling a pump request.
• The water source heat pump compressor delay timer starts; and
• Allows the compressor to start after the delay time has expired.
After the last compressor in the circuit turns off, the controller:
• Forces the water source heat pump water valve for that circuit to open 100% for five (5) minutes; and
• Starts the water source heat pump compressor delay timer to delay notifying the BMS to turn the pump off; and
• Notifies the BMS to stop the pump via:
• Hardwired output by opening the contact on the board; and
• BMS-communicated point by disabling a pump request.
Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
Sequences of Operation
Figure 75: Compressor Envelope Example (see Zone Descriptions).
2
9
Evaporator Temperature
CONTROLLER
3
4
1
6
7
8
5
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