SERVICING
16
2000 microns, moisture and non-condensables are still
present. If gauge continues to rise a leak is present.
Repair and re-evacuate.
7. Close valve to micron gauge and vacuum pump. Shut
off pump and prepare to charge.
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 is not
covered by the warranty. Most portable machines
cannot clean used refrigerant to meet AHRI Standards.
CAUTION
Damage to the unit caused by operating the compressor
with the suction valve closed is not covered under the
warranty and may cause serious compressor damage.
Charge the system with the exact amount of refrigerant.
See the Installation Manual for the correct refrigerant
charge.
An inaccurately charged system will cause future problems.
1. When using an ambient compensated calibrated
charging cylinder, allow liquid refrigerant only to enter
the high side.
2. Once the system stops taking refrigerant, close the valve
on the high side of the charging manifold.
3. Start the system and charge the balance of the refriger-
ant 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 sys-
tem. 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 65°F to 105°F. If out-
door ambient temperature is out of range, charge defined
amount and don’t adjust subcooling. Set the room thermo-
stat to CHARGE mode.
After system has stabilized per startup instructions, check
subcooling as detailed in the following section.
In the event of system overcharge or undercharge, refrig-
erant in the system must be adjusted to the appropriate
subcooling and superheat as specified in the following
sections. Refrigerant amount should be adjusted within
+/- 0.5 lb. if the outdoor ambient temperature is greater than
65°F and less than 105°F. Manufacturer recommends that
the system should be evacuated and should be charged
the initial refrigerant for given line length when the ambient
temperature is less than 65°F and more than 105°F. Refer
to the Installation Manual to calculate refrigerant amount.
5. With the system still running, remove hose and reinstall
both valve caps.
6. Check system for leaks.
NOTE:
Subcooling information is valid only while the unit is
operating at 100% capacity or 100% of compressor speed
in CHARGE MODE. Compressor speed is displayed under
STATUS menu in the thermostat.
CHECKING COMPRESSOR EFFICIENCY
The reason for compressor inefficiency is that the com
-
pressor is broken or damaged, reducing the ability of the
compressor to pump refrigerant vapor.
The condition of the compressor is checked in the following
manner.
1. Attach gauges to the high and low side of the system.
2. Start the system and run CHARGE MODE.
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 - re-
place the compressor.
CHECKING SUBCOOLING
Refrigerant liquid is considered subcooled when its tem-
perature is lower than the saturation temperature corre-
sponding to its pressure. The degree of subcooling equals
the degrees of temperature decrease below the saturation
temperature at the existing pressure.
1. Attach an accurate thermometer or preferably a thermo-
couple type temperature tester to the liquid service valve
as it leaves the condensing unit.
