LG AR-DR12-05A Installation And Operation Manual page 126

CONTROLLER
Sequences of Operation
Water Source Heat Pump, continued.
Entering Water Temperature Alarms: The following alarms occur based on coaxial coil entering water temperatures:
• An entering water temperature alarm activates:
• When cooling and entering water temperature is greater than set-point; or
• When heating and entering water temperature is less than set-point.
• The controller responds to an entering water temperature alarm:
• When heating, it displays a low entering water temp alarm.
• When cooling, it displays a high entering water temp alarm.
• An entering water temp alarm automatically resets:
• When cooling and entering water temperature is less than set-point; or
• When heating and entering water temperature is greater than set-point.
Coax Coil Defrost, Heating: In heating mode, a water source heat pump may need to initiate a defrost cycle of the water coil to prevent a
complete freeze.
1. Initialized: The saturated suction temperature determines when a defrost cycle occurs. The following conditions must be true:
• Saturated suction temperature is less than the fluid freeze temperature set-point; and
• Cold weather start is not active; and
• The unit has controls enabled.
2. Termination: The defrost cycle terminates when the active circuit's saturated suction temperature is greater than the cancel set-point. At
defrost cycle termination, the unit reverts back to heating mode operation.
3. Water Source Heat Pump Heating Lockout: Water source heat pump heating mode is unavailable when:
• The water source heat pump defrost cycle continues for more than the maximum defrost time; or
• A defrost cycle is initiated three times in any one-hour period.
• Each strike created by a defrost mode entry clears one hour after the strike occurs.
4. Water Source Heat Pump Heating Lockout Reset: The water source heat pump heating lockout resets when:
• The water source heat pump heating lockout occurred more than two (2) hours prior; and
• The saturated suction temperature is greater than or equal to the cancel set-point; or
• If the maximum defrost time triggered the lockout, the outside air temperature is greater than the fluid freeze temp set-point plus 10°F.
Supply Fan Modulation: In heating mode, if the supply air temperature is less than 60°F, the supply fan speed decreases to maintain 60°F.
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