Table of Contents
Advertisement
h. Disconnection of the suction pressure transducer will
cause an "A15" alarm. Once the transducer is recon-
nected, the alarm will go to inactive and can then be
cleared.
4.15 TEMPERATURE SENSOR CHECKOUT
a. An accurate ohmmeter must be used to check resist-
ance values shown in Table 4-1.
b. Due to variations and inaccuracies in ohmmeters,
thermometers or other test equipment, a reading
within two percent of the chart value would be consid-
ered acceptable. If a sensor is bad, the resistance val-
ue would usually be much higher or lower than the
value given in Table 4-1 .
c. At least one sensor lead must be disconnected from
the controller before any reading can be taken. Not
doing so will result in a false reading. Two preferred
methods of determining the actual test temperature
at the sensor are an ice bath at 32°F (0°C) and/or a
calibrated digital temperature meter.
Table 4-1. Temperature Sensor Resistance
Temperature
°
°
F
C
--20
--28.9
--10
--23.3
0
--17.8
10
--12.2
20
-- 6.7
30
-- 1.1
32
0
40
4.4
50
10.0
60
15.6
70
21.1
77
25
80
26.7
90
32.2
100
37.8
110
43.3
120
48.9
4.16 PRESSURE TRANSDUCER CHECKOUT
NOTE
System must be operating to check transduc-
ers.
a. With the system running use the driver display and
manifold gauges to check suction and/or discharge
pressure(s) simultaneously.
b. Determine with the gages whether one or both pres-
sure readouts are correct. If one is correct, exchange
T-356
Resistance In Ohms
165,300
117,800
85,500
62,400
46,300
34,500
32,700
26,200
19,900
15,300
11,900
10,000
9,300
7,300
5,800
4,700
3,800
the pressure transducer locations. If the problem
moves with the transducer replace the faulty trans-
ducer.
c. If the driver display read out disagrees with both val-
ues shown on the manifold gauges proceed to step d.
Use care when checking/manipulating
wires/plugs attached to the Logic Board.
Damage to the board or wiring harness can
occur.
d. Verify that the wiring to the transducer(s) is in good
condition.
e. Use a digital volt--ohmmeter to measure voltage
across the transducer connector corresponding to
terminals A & B. See Figure 4-14. The reading should
be 5.0 VDC.
f. Use a digital volt--ohmmeter to measure wire continu-
ity between the connector positions corresponding to
C and J6--23(Suction) or C and J6--20(Discharge).
See Figure 1-6 or Figure 5--2.
g. Use a digital volt--ohmmeter measure voltage across
the transducer at terminals A & C. See Figure 4-14.
Compare to values in Table 4-2. A reading within two
percent of the values in the table would be considered
good.
Figure 4-14 Transducer Terminal Location
4.17 REPLACING SENSORS AND TRANSDUCERS
a. Place main battery disconnect switch in OFF position
and lock.
b. Tag and disconnect wiring from defective sensor or
transducer.
c. Remove and replace defective sensor or transducer.
Sensor/transducer connections are fitted with
Schreader valves to facilitate replacement.
d. Connect wiring to replacement sensor or transducer.
e. Checkout replacement sensor or transducer. (Refer
to section 4.15 or 4.16, as applicable.)
f. Repair or replace any defective component(s), as re-
quired.
4--12
CAUTION
C
B
A
03/11
Advertisement
Table of Contents
