27
RSMD-CM Technical Guide
TROUBLESHOOTING
Suction Pressure 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 RSMD-CM Module(s). The VCCX2 and
the RSMD-CM Module(s) must be powered for this test. Read
voltage with the meter set on DC volts. Place the positive lead
from the meter on the SP1/SP2 terminal located on the RSMD-CM
Module(s) terminal block. Place the negative lead from the meter
on the ground (GND) terminal located adjacent to the SP1/SP2
terminal on the RSMD-CM Module(s) 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/SP2 and GND terminals and
compare it to the appropriate chart depending on the refrigerant
you are using. If the temperature/voltage or pressure/voltage
readings do not align closely with the chart, your Suction Pressure
Transducer is probably defective and will need to be replaced.
See the Suction Pressure Transducer, Pressure, Temperature, and
Voltage Chart for R410-A Refrigerant testing. The chart shows
a temperature range from 20°F to 80°F. For troubleshooting
purposes, the DC Voltage readings are also listed with their
corresponding temperatures and pressures.
Table 4: Suction Pressure Transducers
Coil Pressure/Temperature/Voltage
Chart for R410-A Refrigerant
Suction Pressure Transducer
Coil Pressure – Temperature – Voltage
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
143.2
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
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
Summary of Contents for RSMD-CM
Page 1: ...RSMD CM Technical Guide ...
