8-3262-11039
8.20.3 Replacing Compressor Discharge Pressure
T ransducer
a. Pump down the compressor. (Refer to Section
8.10.1.) Frontseat both suction and discharge ser-
vice valves to isolate compressor.
b. Equalize compressor discharge and suction pres-
sures through the service valve gauge set.
c. Disconnect wiring from defective transducer and re-
move. The CDP is located at the side of the center
compressor cylinder head. (See Figure 2-2)
WARNING
The Compressor Discharge Pressure
T ransducer does not have a Schrader valve
in the connecting fitting. Any discharge
pressure remaining in the compressor will
be released when removing the CDP.
d. Calibrate new discharge transducer before installing
in compressor. (Refer to Section 8.20.1)
e. Install new discharge transducer, being careful to ob-
tain the correct transducer for your unit. R-404A
CDPs have a red dot on the side.
NOTE
Place unit in Service Mode before performing
the following operations on the unit. Refer to
Section 5.2
f. Evacuate and dehydrate the compressor. (Refer to
Section 8.12.)
g. Check unit operation by running Pretrip (Refer to Sec-
tion 3.5).
8.21 COMPRESSOR SUCTION PRESSURE TRANSDUCER (CSP AND EVOP)
LOW RANGE PRESSURE TRANSDUCER
-- CSP/EVOP
OUTPUT VOL TAGE WITH
5V SUPPLY (VOLTS)
PRESSURE (PSIG)
8.21.1 Calibrating Compressor Suction Pressure
T ransducer
The Compressor Suction Pressure Transducer (CSP)
has a range of --14.7 to100 PSIG (--1 to 6.8 Bar).
Because of this much smaller range, calibration of the
CSP is not required.
8.21.2 Testing Compressor Suction Pressure
T ransducer
a. Verify that the wiring to the transducer is correct.
(See wiring diagram, Section 10).
b. Power up the transducer circuit. Place unit into PC
Mode (Refer to Section 5.1), or place unit in Manual
Start Mode.
c. Check Voltage to transducer. Voltage reading be-
tween A (negative) and B (positive) should be 5.0
VDC.
d. Check wire resistance between C (output to micro-
processor) and 1MP6.
e. Place +5.0 VDC on transducer terminal B and --5.0
VDC on transducer terminal A. Test voltage between
B and C. The reading should be as shown in table be-
low.
Table 8-6. Compressor Suction Pressure Transducer
PSIG Bar Voltage PSIG Bar Voltage PSIG Bar Voltage
-- 1 0 -- 0 . 7 0.7 30 2.0 2.1 70 4.8 3.5
-- 5 . 0 -- 0 . 3 0.8 35 2.4 2.2 75 5.1 3.6
0.0 0.0 1.0 40 2.7 2.4 80 5.4 3.8
5.0 0.3 1.2 45 3.1 2.6 85 5.8 4.0
10.0 0.7 1.4 50 3.4 2.8 90 6.1 4.1
15.0 1.0 1.5 55 3.7 2.9 95 6.5 4.3
20.0 1.4 1.7 60 4.1 3.1 100 6.8 4.5
25.0 1.7 1.9 65 4.4 3.3
To Next Page
Loading...