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side the cover of the enclosure. Wye–delta starters
employ three contactors which are controlled sequen-
tially to provide low current starting. For wye–delta
starters, the motor nameplate amps must be first multi-
plied by 0.577 before using the heater table.
Optional Switches – The “Auto Sentry” controller has
one additional input available for dealer or user
installed optional shutdown switches. If the contact is
opened, the compressor will be shut down, and will dis-
play “HIGH VIBRATION.”
COMPRESSOR CAPACITY CONTROL – TURN
VALVE UNITS ONLY
The capacity of the compressor is controlled by the ac-
tion of the Turn Valve and the Compressor Inlet Valve.
The turn valve controls compressor delivery to match
demands of 40% to 100% of the compressor’s maxi-
mum capacity. The inlet valve throttles to control com-
pressor delivery to match demands of 0% to 40% of the
compressors maximum capacity.
Example with normal setting of 100 PSIG:
Discharge
Compressor Manifold
Delivery Inlet Valve Turn Valve Pressure
Full Capacity Open Closed 100
70% Capacity Open 50% Open 100
40% Capacity Open Full Open 100
30% Capacity Closing Full Open 103
20% Capacity Closing Full Open 103
0% Capacity Closed Full Open 103
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