TechPlus ComfortAire, Service Supplement Manual

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10.Allow the correct charge (refer to s pec’s) to enter the system. Then close
the valve on the refrigerant drum and the high side valve on the gauge
manifold.
Checking the Refrigerant Charge
If the unit has an insufficient charge, the evaporator will be “starved” and the
temperature will rise in the vehicle even though the unit is running. Also, an
insufficient charge does not circulate enough oil to properly lubricate the
compressor. The charge may be determined with the following conditions
established:
1. Install a gauge manifold set or charging station.
2. Run the unit at its coldest setting, blowers on high speed, and all windows
and doors closed on the vehicle.
3. The discharge pressure should coincide with the temperature/pressure
chart.
4. If pressures are low, check for leaks, if no leaks exist, charge the
refrigerant with vapor through the low side.
Checking the Compressor Oil Charge
Generally there is enough oil charge in the compressor to handle a system with a
refrigerant charge of 3 lbs. With these systems being larger an additional an
additional 5 oz of oil should be added to each system during a charge. The
compressor is filled with PAG oil (Poly Alkylene Glycol).
Oil must be added at the suction port on the compressor prior to vacuuming the
system, or use an automatic oil injector found on most charging stations.
The other instance when oil may need to be added to the system is when there is
a refrigerant leak, or when the evaporator, condenser, or receiver drier need to
be replaced, 1 once of oil should be added for each component replaced.
Returning oil to the compressor – Open all doors and windows – Turn A/C fan on
high – run unit at idle for 20 minutes.
Always measure oil removed and install the same measurement when replacing.
High Pressure Binary Switch
The High Pressure Binary Switch is found on the receiver drier. If the discharge
pressure reaches 384 psi, the HP Binary switch de energizes the compressor
clutch. Also if high side pressure is below 28 psi, the HP Binary switch will
disengage the compressor clutch.
To test a HP Binary switch re-work a gauge manifold high side as shown in the
following illustration:
1
APPENDIX
c O m F O r t A i r e A / c s Y s t e m s
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