Main Chiller Controller Technical Guide
SECTION 4:
TROUBLESHOOTING
39
Discharge Pressure Transducer Testing
Discharge Pressure Transducer
Testing 0-500 PSI
The Discharge Pressure is obtained by using the Discharge Pressure
Transducer, which is connected into the Discharge Line of the
Compressor.
Use the voltage column to check the Discharge Pressure Transducer
while connected to the Compressor Circuit Module. The Module
must be powered for this test. Read voltage with a meter set on DC
volts. Place the positive lead from the meter on the DP input terminal
located on the Module. Place the negative lead from the meter on
the ground (COM) terminal located adjacent to the DP terminal on
the Module. Use a refrigerant gauge set to measure the suction line
pressure near where the Discharge Pressure Transducer is connected
to the discharge line. Measure the Voltage at the terminals DP and
COM terminals and compare it to the appropriate chart depending
on the refrigerant you are using. If the pressure/voltage readings do
not align closely with the chart, your Discharge Pressure Transducer
is probably defective and will need to be replaced.
Discharge Pressure Transducer
– Temp/Pressure/Voltage Chart for R134a
Refrigerant 0-500 PSI
Temper
atur
e
°F
Pr
essur
e
PSI
Signal DC V
olts
Temper
atur
e
°F
Pr
essur
e
PSI
Signal DC V
olts
10
12
0.596
90
104.3
1.335
15
15.1
0.621
95
113.9
1.411
20
18.4
0.647
100
124.1
1.493
25
22.1
0.677
105
134.9
1.579
30
26.1
0.709
110
146.3
1.671
35
30.4
0.743
115
158.4
1.767
40
35
0.78
120
171.1
1.869
45
40
0.82
125
184.5
1.976
50
45.4
0.863
130
198.7
2.09
55
51.2
0.91
135
213.5
2.208
60
57.4
0.959
140
229.2
2.334
65
64
1.012
145
245.6
2.465
70
71.1
1.069
150
262.8
2.603
75
78.6
1.129
155
281
2.748
80
86.7
1.194
160
299.9
2.899
85
95.2
1.262
Table 7: Temperature/Pressure/Voltage for
Discharge Pressure Transducers