Page 34 - Select Specialty

"Oil-Less” Scroll Medical Air Medical Systems

3.0 System Operation (continued)

3.6 Emergency Shutdown / Alarms

The following conditions may arise during operation.

High Air Temperature Shutdown - This will shut down the compressor in question and will not re-start until
the appropriate red push button is pressed on the main control panel. Before allowing the unit to re-start, the
condition should be checked (see “Compressor runs hot” in the Troubleshooting Section 4.0). Even after
pushing the button, the unit may not re-start, depending on system sequencing and system pressure.

Motor Overload Shutdown - This will shut down the compressor in question and will not re-start until the
reset button on the starter inside the main control cabinet is reset. See “Motor overheating” in the
Troubleshooting Section 4.0.

Lag Unit Running Alarm - This alarm will activate if the last available compressor unit comes on. In the
case of a duplex system, it will activate when the second compressor turns on or the lag pressure switch (PS-2)
closes. To silence the alarm, press the amber push button. In the event the lag alarm is persistent, check to see
if any leaks or valves are open downstream or reduce the system load.

Dryer Tower Switching Failure Alarm (Optional) - For units with this feature, there is one pressure switch
that senses pressure inside each dryer tower for a total of four pressure switches. If the pressure in both towers
of the same dryer fall below 50 psig, the “dryer fault” light will come on and the remote dryer switching
failure contacts will change condition (refer to the wiring diagram that came with the unit for terminal
numbers). A short time delay (1.5 seconds) is started when both pressure switches fall below 50 psig to
eliminate false alarms during normal tower switching. To eliminate alarms during periods when the dryer is
turned “off” for maintenance or other reasons, the dryer tower switching failure alarm is bypassed for that
dryer. Please note there is only one set of remote alarm contacts that will be activated in the event that either
dryer has an alarm condition.

Low Dryer Outlet Pressure Alarm (Optional) - For units with this feature, there is an adjustable pressure
switch located upstream of the dryer check valve that will alarm if the pressure in that line drops below the 75
psig factory setpoint. In the event of an alarm, the “dryer fault” light will come on and a remote set of contacts
will change condition (refer to the wiring diagram that came with the unit for terminal numbers).

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