RWB II ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
S70-200 IOM
Page 32
0.10 VDC to read between 1.38 VDC and 1.62 VDC.
5. Isolate the oil pressure transducer PE-1 from the package
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 barometric de-
viation.
8. Isolate transducer PE-2 from the package and depressur-
ize. NOTE: Recover or transfer all refrigerant vapor, in
accordance with local ordinances, before opening to at-
mosphere.
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 requirements), close all transduc-
ers from atmosphere and open them to their sensing points
so all transducers can equalize to separator pressure.
12. Measure the voltage of PE-3 on connector P4 (terminals
WHT and BLK) on the SBC.
13. Measure the voltage of PE-1 on connector P4 (terminals
WHT and BLK) on the SBC.
14. These two voltages should be within .04 VDC of one an-
other.
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 compressor
package. Follow "General Instructions For Replacing
Compressor Unit Components" before going to step 3.
3. Open the microprocessor control panel.
4. Use the chart to identify transducer terminals of the Ana-
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 transdu-
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
extends out of the conduit hole in the transducer manifold.
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
LOOSEN OR TIGHTEN TRANSDUCERS 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-
connect them to the terminal strip. See Analog Board lay-
outs in S90-010 M (Quantum panel) or SBC wiring diagram
in S70-200 OM (Plus panel) .
11. Close the microprocessor control panel.
12. Reopen the transducer isolation valve.
13. Turn on control power.
