Carrier 69NT40-541-306, Операция и обслуживание

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T-354 7–30
3. Remove the piston by loosening the Allen screw and removing the piston and screw.
4. Install the powerhead assembly (without the piston) and torque to 35 to 40 foot-lbs.
5. Open all valves.
6. Start the unit.
7. Adjust the suction service valve so that the approximate temperature OR current limit is maintained. For per-
ishable loads, it is recommended that the adjustment be made so that the available capacity is slightly larger
than the load. The unit will cycle OFF and ON.
8. Once repair parts become available, repair as required.
7.20 DPRV CHECK PROCEDURE
The discharge pressure regulating valve (DPRV) is designed to maintain a minimal level of pressure within the
compressor. Refer to
Section 3.2 for valve setting.
The following procedure can be used to perform a functional check:
1. Install a high pressure gauge at the discharge service valve.
2. Install another high pressure gauge at the liquid line service valve.
3. Run unit with -18

C (0

F) set point.
4. After five minutes, read both gauges and subtract the liquid line pressure from the discharge pressure. This
is the actual differential pressure.
5. Using the ambient temperature and the chart below, determine the replacement differential pressure.
Figure 7.26 DPRV Replacement Value Chart
NOTE
This test should not be run below -1.1

C (30

F) or above 49

C (120

F). If the actual differential pres-
sure is close to the replacement differential pressure, it is recommended that the readings be taken
several times at two minutes intervals.
NOTE
If valve cap is found to be leaking it may be replaced using cap & O-ring (Carrier Part Number 40-
50024-00).
0
10
20
30
40
50
60
70
30 40 50 60 70 80 90 100 110 120
Ambient Temperature (F)
R
e
p
lacem
en
t
D
iffer
e
n
tial
P
ressu
re
(p
si)
REPLACE DPRV
DO NOT REPLACE DPRV