GSX14 Service Manual

SERVICING
147
7. Close valve to thermocouple vacuum gauge and vacuum
pump. Shut off pump and prepare to charge.
S-103 CHARGING
WARNING
REFRIGERANT UNDER PRESSURE!
* Do not overcharge system with refrigerant.
* Do not operate unit in a vacuum or at negative
pressure.
Failure to follow proper procedures may cause
property damage, personal injury or death.
CAUTION
Use refrigerant certified to AHRI standards. Used
refrigerant may cause compressor damage and will
void the warranty. Most portable machines cannot
clean used refrigerant to meet AHRI standards.
CAUTION
Operating the compressor with the suction valve
closed will void the warranty and cause serious
compressor damage.
Charge the system with the exact amount of refrigerant.
Refer to the specification section or check the unit name-
plates for the correct refrigerant charge.
An inaccurately charged system will cause future prob-
lems.
1. When using an ambient compensated calibrated charg-
ing cylinder, allow liquid refrigerant only to enter the high
side.
2. After the system will take all it will take, close the valve on
the high side of the charging manifold.
3. Start the system and charge the balance of the refrigerant
through the low side.
NOTE: R410A should be drawn out of the storage container
or drum in liquid form due to its fractionation properties, but
should be "Flashed" to its gas state before entering the
system. There are commercially available restriction devices
that fit into the system charging hose set to accomplish this.
DO NOT charge liquid R410A into the compressor.
4. With the system still running, close the valve on the
charging cylinder. At this time, you may still have some
liquid refrigerant in the charging cylinder hose and will
definitely have liquid in the liquid hose. Reseat the liquid
line core. Slowly open the high side manifold valve and
transfer the liquid refrigerant from the liquid line hose and
charging cylinder hose into the suction service valve port.
CAREFUL: Watch so that liquid refrigerant does not
enter the compressor.
Final Charge Adjustment
The outdoor temperature must be 60°F or higher. Set the
room thermostat to COOL, fan switch to AUTO, and set the
temperature control well below room temperature.
After system has stabilized per startup instructions, compare
the operating pressures and outdoor unit amp draw to the
numbers listed on the performance label on the outdoor unit.
If pressures and amp draw are too low, add charge. If
pressures and amp draw are too high, remove charge.
Check subcooling and superheat as detailed in the following
section.
5. With the system still running, remove hose and reinstall
both valve caps.
6. Check system for leaks.
Do not charge a remote condensing unit with a non-matching
evaporator coil, or a system where the charge quantity is
unknown. Do not install or charge R410A condensers
matched with coils having capillary tubes or flow control
restrictors. AHRI rated Coil combinations with thermostatic
expansion valves (TEV's) should be charged by subcooling.
See "Checking Subcooling and Superheat" sections in this
manual. Subcooling values for "Ultron" system are found in
the Technical Information manuals for "Ultron" outdoor units.
Due to their design, Scroll compressors are inherently more
tolerant of liquid refrigerant.
NOTE: Even though the compressor section of a Scroll
compressor is more tolerant of liquid refrigerant, continued
floodback or flooded start conditions may wash oil from the
bearing surfaces causing premature bearing failure.
S-104 CHECKING COMPRESSOR EFFICIENCY
The reason for compressor inefficiency is broken or dam-
aged scroll flanks on Scroll compressors, reducing the ability
of the compressor to pump refrigerant vapor.
The condition of the scroll flanks is checked in the following
manner.
1. Attach gauges to the high and low side of the system.
2. Start the system and run a "Cooling Performance Test.
If the test shows:
a. Below normal high side pressure.
b. Above normal low side pressure.
c. Low temperature difference across coil.
d. Low amp draw at compressor.
And the charge is correct. The compressor is faulty - replace
the compressor.