York YLAA0195HE, Manual, Page: 183 / 206

183
JOHNSON CONTROLS
FORM 150.72-NM3 (1020)
ISSUE DATE 10/05/2020
SECTION 9 – SERVICE AND TROUBLESHOOTING
9
Analog Inputs – Pressure
Refer to the unit wiring diagram. Pressure inputs
are connected to the microboard on plugs J7 and J9.
These analog inputs represent varying DC signals
corresponding to varying pressures. All voltages are in
reference to the unit case (ground).
System 1 discharge and suction pressures will be
connected to J7 of the microboard. System 2 discharge
and suction pressure transducers will be connected to
J9 of the microboard.
The discharge transducers are optional on all units. If the
discharge transducers are not installed, no connections
are made to the microboard and the discharge pressure
readout on the display would be zero.
The suction pressure transducers are standard on all
YLAA’s. The suction pressure transducers have a range
of 0 to 400 PSIG. The output will be linear from 0.5VDC
to 4.5VDC over the 400 PSIG (27.5 barg) range.
The discharge transducers have a range from 0 to 650
PSIG. The output will be linear from 0.5VDC to 4.5VDC
over the 600 PSIG (41.25 barg) range. The following is
the formula that can be used to verify the voltage output
of the transducer. All voltage reading are in reference to
ground (unit case).
TEST POINTS:
Suction Pressure:
System 1: ...........................Microboard J7-10 to J7-9
System 2: ...........................Microboard J9-10 to J9-9
Discharge Pressure:
System 1: ...........................Microboard J7-11 to J7-7
System 2: ...........................Microboard J9-11 to J9-7
V = (Pressure in PSIG x .01) + .5
or
V = (Pressure in BARG x .145) + .5
where V = dc voltage output
Pressure = pressure sensed by transduce
r
The I/O board connections for the Discharge
Transducers:
System 1 Discharge Transducer
J7-6 = +5VDC regulated supply to transducer.
J7-11 = VDC input signal to the microboard.
See
the formula above for voltage readings
that correspond to specific discharge
pressures.
J7-7 = +5VDC return
J7-2 = drain (shield connection = 0VDC)
System 2 Discharge Transducer
J9-6 = +5VDC regulated supply to transducer.
J9-11 =VDC input signal to the microboard. See the
formula above for voltage readings that
correspond to specific discharge pressures.
J9-7 = +5VDC return
J9-2 = drain (shield connection = 0VDC)
TABLE 26 – PRESSURE TRANSDUCERS
0-400 PSIG SUCTION
PRESSURE
TRANSDUCER
0-600 PSIG DISCHARGE
PRESSURE
TRANSDUCER
PRESSURE
PSIG
VOLTAGE
VDC
PRESSURE
PSIG
VOLTAGE
VDC
0 0.5 0 0.5
50 1.0 75 1.0
100 1.5 150 1.5
150 2.0 225 2.0
200 2.5 300 2.5
250 3.0 375 3.0
300 3.5 450 3.5
350 4.0 525 4.0
400 4.5 600 4.5
RED WIRE = 5V, BLACK WIRE = 0V, WHITE/GREEN WIRE = SIGNAL