Gardner Denver APEXVS7-11A, Operating And Service Manual

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13-25-603 Page 33
Magnetic Unloader Solenoid Valve (Figure 4-3, page 29) - This valve controls the position of the inlet
valve in response to signals from the AirSmart Controller. During stopped operation, the unloader valve
supplies compressed air under the poppet to close the inlet valve. During run operation, the unloader
valve vents the underside of the poppet, allowing it to open.
Check Valve (Figure 4-3, page 29) - This valve is normally closed while the compressor is loaded or
stopped. While running unloaded, it opens to admit a small amount of purge air to the compressor inlet.
This reduces compressor knock, and provides enough air to pressurize the controls during startup.
Blowdown Valve (Figure 4-3, page 29) - The blowdown valve is a two-way solenoid valve which is piped
into the oil reservoir outlet ahead of the minimum pressure valve. When the solenoid is de-energized, the
valve opens and the coolant system is blown down. When the solenoid is energized, the valve closes to
allow the coolant system to pressurize.
Plant Pressure Transducer (Figure 4-3, page 29) - This transducer is connected after the minimum
pressure valve. It converts the pressure in the plant air system into an electrical signal for use by the
"AirSmart" controller for modulation and control.
Reservoir Pressure Transducer (Figure 4-3, page 29) - This transducer is connected to the coolant
system. Its signal is used to prevent loaded starts, monitor oil pressure, and to monitor the condition of
the separator.
Air Filter Vacuum Switch (Figure 4-3, page 29) - This switch is used to monitor air filter condition and
alert the user if the filter requires service or replacement.
Machine damage will occur if compressor is repeatedly restarted after any one
of the shutdown modes stops operation of the unit. Find and correct the
malfunction before resuming operation.
Discharge Thermistor
(Figure 4-3, page 29) - This sensor is located directly in the compressor
discharge. Its signal is used to monitor compressor temperature and shut down the compressor if a
coolant problem is detected.
Reservoir Thermistor (Figure 4-3, page 29) - This sensor is located in the reservoir/separator housing
and is used to monitor temperature and shut down the compressor if temperature problems occur at the
separator.
Emergency Stop Pushbutton - This is a maintained pushbutton, and removes power from the controller
outputs regardless of controller status. It is located on the middle section of the control box door, below
the keypad. This should be used for emergency purposes only - use the keypad [STOP/RESET] for
normal controlled stopping.
Automatic restarting or electrical shock can cause injury or death. Open
lockout and tagout main disconnect and any other circuits before servicing
unit.