Table of Contents
Advertisement
c. With the voltmeter set to read 50 volts DC, attach the
positive lead to outlet pin "A" of the six pin connector,
and the negative lead to pin "B" or TP-9 of the con-
troller.
d. Turn ON the unit for 40 seconds, and watch the volt-
meter. There should be approximately 24 to 32 VDC
shown on pin "A".
e. There should be zero volts on pin "B".
f. After a short delay, the reading should rise to approx-
imately 24 to 32 VDC on pin "E".
g. Pins "C" and "D" will have zero to 5 volts transistor
logic (TTL) signals present, however, this can only
be checked with the connector assembled as this is
an open collector type circuit.
By checking the outputs on "A," "B," and "E" it can be
verified that the controller is supplying power to the drive
module. To be thorough, and if it is desired, the signals
on pins "C" and "D" can be checked as follows:
1. Install a jumper assembly (Carrier part number
07--00408--00) to connect the drive module and con-
troller connectors as shown in Figure 45.
2. Connect the positive lead of the voltmeter to test
connector socket "C" and negative lead to socket
"B," and run as before by resetting unit.
3. Repeat for sockets "D" and "B."
Controller
Drive Module
Connector (EC)
Connector (SD)
A
B
C
D
E
Test
Connector
Figure 45. Jumper Assembly
There should be approximately five volts DC on sockets
"C" and "D" (S1 and S2) when measured as above. If not
the connections or controller is faulty.
If any of these pins are not consistent, the connections
or controller is suspect. Check and replace as required.
6.18.5 Emergency Repair Procedures:
In the event that the SMV system has a failure and
replacement components are not readily available the
system can be by--passed by removing the valve piston.
to remove the piston, do the following:
a. Perform a low side pump down. Refer to section 6.4,
page 59.
b. Remove SMV powerhead by loosening the 2-1/8
inch diameter nut (see Figure 45) to relieve any pres-
sure and then , sliding the powerhead out.
c. Remove the piston by loosening the Allen screw and
removing the piston and screw.
d. Install the powerhead assembly (without the piston),
torque to 35 to 40 foot-lbs.
A
B
C
D
E
Jumper
e. Open all valves.
f. Start the unit.
g. Adjust the suction service valve so that the approxi-
mate temperature OR current limit is maintained.
For perishable loads, it is recommended that the ad-
justment be made so that the available capacity is
slightly larger than the load, the unit will cycle OFF
and ON.
h. Once repair parts become available, repair as re-
quired.
6.19 DISCHARGE PRESSURE REGULATOR
VALVE CHECK PROCEDURE
The discharge pressure regulator valve (DPRV) is
designed to maintain a minimal level of pressure within
the compressor. Refer to paragraph 2.2, page 11, for
valve setting.
The following procedure can be used to perform a
functional check:
a. Install a high pressure gauge at the discharge service
valve.
b. Install another high pressure gauge at the liquid line
service valve.
c. Run unit with -18 C (0 F) set point.
d. After five minutes, read both gauges and subtract the
liquid line pressure from the discharge pressure. This
is the actual differential pressure.
e. Using the ambient temperature and the chart below,
determine the replacement differential pressure.
Replacement Differential Pressure Bar (psig)
4.76
(70)
4.08
(60)
3.40
(50)
2.72
(40)
2.04
(30)
DO NOT REPLACE DPRV
1.36
(20)
0.68
(10)
0
- -1
4
10
(30)
(40)
(50)
Ambient Temperature Bar (F)
DPRV Replacement Value Chart
1. This test should not be run below -1.1 C
(30 F) or above 49 C (120 F). If the actual
differential pressure is close to the
replacement differential pressure, it is
recommended that the readings be taken
several times at two minutes intervals.
2. If valve cap is found to be leaking it may be
replaced using cap & O-ring (Carrier Part
Number 40-50024-00).
73
REPLACE DPRV
16
21
27
32
38
(90)
(60)
(70)
(80)
(100)
NOTE
43
49
(110)
(120)
T-305
Advertisement
Table of Contents
Troubleshooting
