36
RSM-DEV1 Technical Guide
TROUBLESHOOTING
Transducer Testing
Suction Pressure Transducer Testing
for R410-A Refrigerant
The evaporator coil temperature is calculated by converting the
suction pressure to temperature. The suction pressure is obtained
by using the Suction Pressure Transducer, which is connected to
the suction line of the compressor.
Use the voltage column to check the Suction Pressure Transducer
while connected to the RSM-DEV1 Module. The VCCX2 and the
RSM-DEV1 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 SP1 terminal located on the RSM-DEV1 Module terminal
block. Place the negative lead from the meter on the ground (GND)
terminal located adjacent to the SP1 terminal on the RSM-DEV1
Module terminal block. Use a refrigerant gauge set and/or an
accurate electronic thermometer to measure the temperature or
suction line pressure near where the Suction Pressure Transducer
is connected to the suction line. Measure the voltage at the SP1 and
GND terminals and compare it to the appropriate chart depending
on the refrigerant in use. If the temperature/voltage or pressure/
voltage readings do not align closely with the chart, the Suction
Pressure Transducer is probably defective and needs to be replaced.
See
Table 18, this page
. The chart shows a temperature range from
21.19°F to 80.18°F. For troubleshooting purposes, the DC voltage
readings are also listed with their corresponding temperatures and
pressures.
SUCTION PRESSURE TRANSDUCER CHART
FOR R410-A REFRIGERANT
Temperature
(°F)
Temperature
(ºC)
Pressure
(psi)
Signal
DC V
olts
21.19
-6.1
80.94
1.8
24.49
-4.4
87.16
1.9
27.80
-2.8
93.39
2.0
30.99
-1.1
99.62
2.1
33.89
0.6
105.84
2.2
36.80
2.2
112.07
2.3
39.71
3.9
118.29
2.4
42.30
5.6
124.52
2.5
44.85
6.7
130.75
2.6
47.39
8.3
136.97
2.7
49.94
9.4
143.20
2.8
52.23
11.1
149.42
2.9
54.50
12.2
155.65
3.0
56.76
13.3
161.88
3.1
59.03
15.0
168.10
3.2
61.17
16.1
174.32
3.3
63.19
17.2
180.55
3.4
65.21
18.3
186.78
3.5
67.23
19.4
193.00
3.6
69.24
20.6
199.23
3.7
71.15
21.7
205.46
3.8
72.95
22.2
211.68
3.9
74.76
23.3
217.91
4.0
76.57
24.4
224.14
4.1
78.37
25.6
230.36
4.2
80.18
26.7
236.59
4.3
Table 18: Suction Pressure Transducer Chart for
R410-A Refrigerant
