Carrier Transicold X4 7300, Operation & Service Manual

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8.9.5 Condenser Pressure Control Solenoid
Valve (SV1)
Figure 8.31 Condenser Pressure Control Solenoid
Valve (SV1)
a. Checkout Procedure
To obtain proper heating and defrost, the normally
open SV1 must energize and close tightly during the
heat and defrost cycles. If the valve does not close
tightly due to physical damage, foreign material or
wear, refrigerant leakage through the valve can reduce
heating capacity.
• During normal heat or defrost cycles the fol-
lowing conditions will be observed when the
valve is operating properly:
1. Receiver refrigerant level will drop quickly at the
initiation of heating or Defrost Mode.
2. Suction pressure will rise slowly to 90-100 PSIG
(6.12 to 6.80 Bar).
3. Discharge pressure will drop quickly, but will
begin to rise to a minimum of 250 PSIG (17.0
Bars) within 15 to 20 minutes.
• If suction and discharge pressures remain
low and the receiver level does not drop, the
valve may be inoperative and can be checked
by the following method.
1. Verify the solenoid coil has proper voltage and is
energized in heating and defrosting.
2. Connect a discharge pressure gauge at the dis-
charge service valve and connect a gauge to
the liquid line service valve.
3. With the refrigerated compartment temperature
at 35°F (1.7°C) or lower, operate the unit in high
speed cool and disconnect the coil.
4. With a separate 12 VDC source, energize the
coil with the unit in high speed cooling and
observe the discharge and receiver pressures. If
the valve is closing properly, compressor dis-
charge pressure will begin to rise and the
receiver pressure will remain the same or begin
to drop slowly. If the valve is not seating prop-
erly, both discharge and receiver pressure will
rise slowly or remain the same.
5. Operate the unit until discharge pressure
reaches 200 PSIG (13.61 Bars) and disconnect
the coil. Discharge and receiver pressure should
be within 5 to 15PSIG (0.34 to 1.02 Bars) of
each other.
b. Replacing The Coil
NOTE
The coil may be replaced without removing
the refrigerant or pumping the unit down.
1. Ensure the unit will not start automatically by
disabling any two way communication, placing
the STOP/RUN-OFF switch in the OFF position
and removing the negative battery cable.
2. Remove top lock nut ( Figure 8.31 ), spacer cup
and nameplate.
3. Disconnect wiring and remove coil. Ensure
spacer is in place.
4. Replace coil by reversing the preceding steps.
Torque coil lock nut 46 to 50 inch/lbs (5.2 to 5.7
Nm).
5. Start unit and run Pretrip to check operation.
c. Replacing Internal Components
CAUTION
!
Service Mode MUST be used whenever
removing refrigerant charge, refrigerant
leak checking or evacuating.
1. Remove the refrigerant charge. (Refer to Sec-
tion 8.7.2 .)
2. Ensure the unit will not start automatically by
disabling any two way communication, placing
the STOP/RUN-OFF switch in the OFF position
and removing the negative battery cable.
3. Remove top lock nut ( Figure 8.31 ), spacer cup,
nameplate, coil and spacer.
Lock Nut
Spacer Cup
Nameplate
Coil
Spacer
Enclosing Tube
Locknut
Enclosing Tube
Plunger
Gasket
Closing Spring
Seat Disc
Body