Service manual

6-- 18T--318
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.
0
10
20
30
40
50
60
70
30 40 50 60 70 80 90 100 110 120
Amb ient Temperature (F)
Replacement Differential Pressu re (psi)
REPLACE DPRV
DO NOT REPLACE DPRV
Figure 6-25 DPRV Replacement V alue Chart
NOTE
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).
6.20 AUTOTRANSFORMER
If the unit does not start, check the following:
a. Make sure the 460 VAC (yellow) power cable is
plugged into the receptacle (item 3, Figure 4-1) and
locked in place.
b. Make sure that circuit breakers CB-1 and CB-2 are in
the “ON” position. If the circuit breakers do not hold in,
check voltage supply.
c. There is no internal protector for this transformer de-
sign; therefore, no checking of the internal protector is
required.
d. Using a voltmeter and with the primary supply circuit
ON, check the primary (input) voltage (460 vac).
Next, check the secondary (output) voltage (230
vac). The transformer is defective if output voltage is
not available.
6.21 CONTROLLER
6.21.1 Handling Controller
CAUTION
Do not remove wire harnesses from con-
troller unless you are grounded to the unit
frame with a static safe wrist strap.
CAUTION
Unplug all controller connectors before
performing arc welding on any part of the
container.
The guidelines and cautions provided herein should be
followed when handling the Controller/DataCORDER
module. These precautions and procedures should be
implemented when replacing the module, when doing
any arc welding on the unit, or when service to the
refrigeration unit requires handling and removal of the
controller.
12
3 4
1. Controller Software 3. Controller
Programming Port
2. Mounting Screw 4. Test Points
Figure 6-26 Contr oller Sec tion of the Control Box
a. Obtain a grounding wrist strap (Carrier Transicold PN
07-00304-00) and a static dissipation mat (Carrier
T ransicold PN 07-00304-00). The wrist strap, when
properly grounded, will dissipate any potential build-
up on the body. The dissipation mat will provide a stat-
ic-free work surface on which to place and/or service
the controller.
b. Disconnect and secure power to the unit.
c. Place strap on wrist and attach the ground end to any
exposed unpainted metal area on the refrigeration
unit frame (bolts, screws, etc.).
d. Carefully remove the controller. Do not touch any of
the electrical connections if possible. Place the mod-
ule on the static mat.