Table 9-1.--A/M27T-5 Main Control Panel Controls and Indicators--Continued.
Indicates hydraulic fluid flow to high pressure port (2 to 30
Adjusts pressure at which compensation occurs in high
pressure pump when power supply is being used as a high
PUMP CASE FILTER indicator
Illuminates when pump case drain filter high differential
pressure switch S3 closes. S3 will close if the pump case
drain filter input and output pressure differ by 35 psi or
LOW PRESS FILTER indicator
Illuminates when low pressure filter high differential
pressure switch S4 closes. S4 will close if low pressure filter
and inlet and outlet pressures differ by 50 psi or more.
Function depends on setting of PRESSURE SELECTOR
VALVE (see 21, below). Calibrated to indicate 0 to 30
inches Hg vacuum and 0 to 300 psi.
Used to calibrate COMPOUND GAUGE when
PRESSURE SELECTOR VALVE is set to CALIBRATE
L.P. GAUGE TEST port
Allows application of hydraulic fluid from external source
for use in testing and calibrating COMPOUND GAUGE.
Used only when PRESSURE SELECTOR VALVE is set to
4-position, 5-way valve. Acts as a hydraulic switch for
connecting COMPOUND GAUGE to hydraulic pump or
power supply return line. H.P. PUMP INLET and BOOST
PUMP INLET settings connect COMPOUND GAUGE to
hydraulic pump high pressure and boost pump inlets,
respectively. RETURN BACK PRESSURE connects
COMPOUND GAUGE to power supply return line.
CALIBRATE GAUGE isolates COMPOUND GAUGE
Panel Light (DS3)
Provides main control panel lighting. Illuminates if ignition
switch S1 is set to IGNITION ON.
PRESSURE BYPASS VALVE
When open, causes HIGH PRESSURE RELIEF VALVE to
dump flow to return line at no pressure.
HIGH PRESS FILTER indicator
Illuminates when high pressure filter high differential
pressure switch S2 closes. S2 will close if high pressure
filter inlet and outlet pressures differ by 100 psi or more.