SERVICING
29
3. If the vacuum pump is working properly, close the valve
to the vacuum thermocouple gauge and open the high
and low side valves to the high vacuum manifold set.
With the valve on the charging cylinder closed, open the
manifold valve to the cylinder.
4. Evacuate the system to at least 29 inches gauge before
opening valve to thermocouple vacuum gauge.
5. Continue to evacuate to a maximum of 500 microns.
Close valve to vacuum pump and hold vacuum for 10
minutes. If the pressure rises to 1,000 microns or less
and remains steady the system is considered leak-free.
6. If pressure rises above 1,000 mircons, but holds steady
below 2,000 microns, moisture and / or noncondensi-
bles may be present or the system may have a small
leak. If pressure rises above 2,000 microns, a leak is
present. Check for leaks and repair as necessary then
repeat evacuation.
7. Close valve to thermocouple vacuum gauge and vacu-
um 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 PRES-
SURE.
FAILURE TO FOLLOW PROPER PROCEDURES MAY CAUSE
PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
WARNING
USE REFRIGERANT CERTIFIED TO AHRI STANDARDS. USED
REFRIGERANT MAY CAUSE COMPRESSOR DAMAGE AND IS
NOT COVERED BY THE WARRANTY. MOST PORTABLE MA-
CHINES CANNOT CLEAN USED REFRIGERANT TO MEET AHRI
STANDARDS.
WARNING
DAMAGE TO THE UNIT CAUSED BY OPERATING THE COM-
PRESSOR WITH THE SUCTION VALVE CLOSED IS NOT COV-
ERED 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 liq
-
uid 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 outdoor
ambient temperature is out of range, charge defined amount
and don't adjust subcooling. Set the room thermostat 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, refriger-
ant in the system must be adjusted to the appropriate sub-
cooling and superheat as specified in the following sections.
Refrigerant amount should be adjusted /- 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 refrig-
erant 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.
S-104 CHECKING COMPRESSOR EFFICIENCY
The reason for compressor inefficiency is that the compres
-
sor is broken or damaged, reducing the ability of the com-
pressor 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.
