JOHNSON CONTROLS
182
FORM 150.67-NM2
ISSUE DATE: 01/31/2019
SECTION 9 – SERVICE AND TROUBLESHOOTING
Liquid and Refrigerant Sensor Test Points
(Table 35 on page 182)
Entering Chilled Liquid Sensor
J6-5 = +5VDC regulated supply to sensor.
J6-8 = VDC input signal to the I/O board. See Table 32
for voltage readings that correspond to specific
liquid temperatures.
J6-2 = drain (shield connection = 0VDC) Return
Leaving Chilled Liquid Temperature Sensor
J6-4 = +5VDC regulated supply to sensor.
J6-7 = VDC input signal to the microboard. See Table
32 for voltage readings that correspond to spe-
cific liquid temperatures.
J6-1 = drain (shield connection = 0VDC) Return
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 correspond-
ing to varying pressures. All voltages are in reference
to the unit case (ground).
System 1 discharge and suction pressures will be con-
nected 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 connec-
tions are made to the microboard and the discharge
pressure readout on the display would be zero.
The suction pressure transducers are standard on all
YCAL’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. Fol-
lowing 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).
TABLE 35 - ENTERING/LEAVING CHILLED LIQUID
TEMP. SENSOR, TEMPERATURE/
VOLTAGE CORRELATION
TEMP °F
VOLTAGE
(SIGNAL INPUT
TO RETURN)
TEMP °C
10 1.33 -12
12 1.39 -11
14 1.46 -10
16 1.51 -9
18 1.58 -8
20 1.65 -7
22 1.71 -6
24 1.78 -4
26 1.85 -3
28 1.91 -2
30 1.98 -1
32 2.05 0
34 2.12 1
36 2.19 2
38 2.26 3
40 2.33 4
42 2.40 6
44 2.47 7
46 2.53 8
48 2.60 9
50 2.65 10
52 2.73 11
54 2.80 12
56 2.86 13
58 2.92 14
60 2.98 16
62 3.05 17
64 3.11 18
66 3.17 19
68 3.23 20
70 3.29 21
72 3.34 22
74 3.39 23
76 3.45 24
78 3.5 26
80 3.54 27