RWB II ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
S70-200 IOM
Page 35
5. Isolate the oil pressure transducer PE-1 from the pack age
and open it to atmosphere.
6. Measure the voltage of PE-1 on connector P4 (terminals
WHT and BLK) on the SBC.
7. The voltage reading should be between 1.1 VDC and 1.29
VDC at standard atmospheric pressure. PE-1, PE-2, and PE-
3 all have a span of 300 PSI as compared to PE-4 with a span
of 100 PSI. Therefore, atmospheric pressure changes have a
lesser effect which is 0.0067 VDC per 1000 feet of elevation
and 0.00067 VDC per 0.1 inch Hg baro met ric de vi a tion.
8. Isolate transducer PE-2 from the package and de pres -
sur ize. NOTE: Recover or transfer all refrigerant va por,
in accordance with local ordinances, before open ing to
at mo sphere.
9. Measure the voltage of PE-2 on connector P4 (terminals
WHT and BLK) on the SBC.
10. The voltage reading should be between 1.1 VDC and 1.29
VDC at standard atmospheric pressure (see Step 12).
11. Since the discharge pressure, PE-3, cannot be closed
off from its sensing point (code require ments), close all
trans duc ers from atmosphere and open them to their sens-
ing points so all trans duc ers can equalize to separator
pres sure.
12. Measure the voltage of PE-3 on connector P4 (ter mi nals
WHT and BLK) on the SBC.
13. Measure the voltage of PE-1 on connector P4 (ter mi nals
WHT and BLK) on the SBC.
14. These two voltages should be within .04 VDC of one
an oth er.
15. Test is complete.
PRESSURE TRANSDUCERS - REPLACEMENT
1. Shut off control power.
2. Close the applicable transducer isolation valve. NOTE:
To change the discharge pressure transducer (PE-3),
it will be necessary to depressurize the entire com-
pres sor pack age. Follow "Gen er al Instructions For
Re plac ing Com pres sor Unit Components" before going
to step 3.
3. Open the microprocessor control panel.
4. Use the chart to identify transducer terminals of the An a log
Board (Quantum panel) or SBC Board (Plus panel).
MANIFOLD
TRANSDUCER
CONNECTION
Oil Pressure
PE-1
Oil Before Filter (PSID) *
PE-2
Discharge Pressure
PE-3
Suction Pressure
PE-4
* Used for Full and Cycling pumps and ext. oil cooler.
5. Disconnect transducer leads by loosening the terminal
screws for the transducer to be changed.
6. Tape a 3 ft. length of pull wire to the leads of the trans du-
cer to be removed.
*
Below 0 PSIG measured in inches of mercury.
PRESSURE TRANSDUCER CONVERSION DATA
200 psi
500 psi
Sensor
Range - PSI
Range - PSIG*
Voltage low high low high
1.0
29.92" 9.57" 29.92" 4.10
1.1
29.92" 0.30 29.92" 16.60
1.2 29.92" 5.30 17.10" 29.10
1.3 19.74" 10.30 4.10 41.60
1.4
9.57" 15.30 16.60 54.10
1.5
0.30 20.30 29.10 66.60
1.6
5.30 25.30 41.60 79.10
1.7
10.30 30.30 54.10 91.60
1.8
15.30 35.30 66.60 104.10
1.9
20.30 40.30 79.10 116.60
2.0
25.30 45.30 91.60 129.10
2.1
30.30 50.30 104.10 141.60
2.2
35.30 55.30 116.60 154.10
2.3
40.30 60.30 129.10 166.60
2.4
45.30 65.30 141.60 179.10
2.5
50.30 70.30 154.10 191.60
2.6
55.30 75.30 166.60 204.10
2.7
60.30 80.30 179.10 216.60
2.8
65.30 85.30 191.60 229.10
2.9
70.30 90.30 204.10 241.60
3.0
75.30 95.30 216.60 254.10
3.1
80.30 100.30 229.10 266.60
3.2
85.30 105.30 241.60 279.10
3.3
90.30 110.30 254.10 291.60
3.4
95.30 115.30 266.60 304.10
3.5
100.30 120.30 279.10 316.60
3.6
105.30 125.30 291.60 329.10
3.7
110.30 130.30 304.10 341.60
3.8
115.30 135.30 316.60 354.10
3.9
120.30 140.30 329.10 366.60
4.0
125.30 145.30 341.60 379.10
4.1
130.30 150.30 354.10 391.60
4.2
135.30 155.30 366.60 404.10
4.3
140.30 160.30 379.10 416.60
4.4
145.30 165.30 391.60 429.10
4.5
150.30 170.30 404.10 441.60
4.6
155.30 175.30 416.60 454.10
4.7
160.30 180.30 429.10 466.60
4.8
165.30 185.30 441.60 479.10
4.9
170.30 190.30 454.10 491.60
5.0
175.30 195.30 466.60 504.10
At 0 psig
1.094 V
1.494 V
0.968 V
1.268 V
7. Pull the transducer leads through the conduit until pull wire
ex tends out of the conduit hole in the transducer man i fold.
Separate the transducer leads from the pull wire.
8. Unscrew the transducer using a wrench on the metal hex at
the base of the transducer. DO NOT ATTEMPT TO LOOS EN
OR TIGHT EN TRANS DUC ERS BY THEIR TOP CASING.
9. Install new transducer and tape leads to the pull wire.
10. Pull new transducer leads into the control panel and
re con nect them to the terminal strip. See Analog Board lay-
outs in S90-010 M (Quantum panel) or SBC wiring di a gram
in S70-200 OM (Plus panel) .
11. Close the microprocessor control panel.
12. Reopen the transducer isolation valve.
13. Turn on control power.
