Daikin SWP Series Installation Manual page 19

Phase Voltage Monitor (PVM)
The phase voltage monitor is designed to help protect
three-phase loads from damaging power conditions . A
microprocessor-based voltage and phase-sensing circuit
constantly monitor the three-phase voltages to detect harmful
power line conditions . When a harmful condition is detected,
its output relay is deactivated after a specified amount of
time (Trip Delay) . The output relay reactivates after power
line conditions return to an acceptable level for a specified
amount of time (Restart Delay) . The trip and restart delays
prevent nuisance tripping due to rapidly fluctuating power line
conditions .
Other features:
• LED display to indicate status (see "1" in
• Loss of phase
• High or low voltage
• Voltage imbalance
• Phase reversal
• Rapid cycling
• Standard 1 to 500 second variable restart delay (see "2"
in Figure 18)
• Standard 2% to 8% variable voltage imbalance (see "3" in
Figure 18)
• Standard 1 to 30 second trip delay (see "4" in
Figure 18: Phase Voltage Monitor
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High Pressure Switches
(ETL Marked Units Only)
The high pressure switch (HP1-HP8) is a single pole pressure
activated device that opens on a pressure rise . When the
switch opens, it de-energizes the compressor circuit, shutting
down the compressor . The MicroTech III controller displays an
alarm condition. Once the cause of the fault is identified and
corrected, manually reset the unit through the MicroTech III
keypad/display interface . The control is attached to a Shrader
fitting and is located at the compressor. To check the control,
shut off water flow to the condensers and observe the cutout
point on a high pressure gauge . The high pressure control
should open at 500 psig and close at 380 psig . After testing
the high pressure control, check the pressure relief device for
Figure 18)
leaks .
Low Pressure Switches
The low pressure switch (LP1-LP8) is a single pole, pressure
activated device that closes on a pressure rise . It senses
evaporator pressure and is factory set to close at 120 psig and
open at 70 psig . Compressor operation is not allowed until the
switch closes . The low pressure switch is an automatic reset
control . If the condition occurs on any one compressor three
times in a 24-hour period, the alarm has to be reset manually
through the MicroTech III keypad/display interface to restart the
Figure 18)
compressor . The low pressure switch is attached to a Shrader
fitting and is located at the compressor.
Compressor Motor Protector
All compressors are thermally protected . The solid state
protection device (MP1-MP8) is located in the compressor
junction box . Whenever the protection system opens, the
compressor shuts down for 30 minutes, and the MicroTech III
controller displays an alarm indication .
The solid state protection device is used on the following:
• Independent circuits—13, 15 hp
The in-line protection control automatically resets when the
alarm condition is removed and the time delay is satisfied.
The in-line protection device is used on the following:
• Independent circuits—6, 8, 10 hp
If the condition occurs on any one compressor three times in
a 24-hour period, the alarm has to be manually reset through
the MicroTech III keypad/display interface to restart the
compressor .
19 IM 1032-2 • Self-Contained Air Conditioning Systems
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