835965-UIM-A-0112
Johnson Controls Unitary Products
17
SECTION VI: SYSTEM CHARGE
1. The factory charge in the outdoor unit includes enough charge for
the unit, a 15 ft. line set and the smallest rated indoor coil match-up.
Some indoor coil matches may require additional charge. See tabu-
lar data sheet provided in unit literature packet for charge require-
ments.
2. Once line size/length and indoor coil adders have been figured,
weigh in this amount of charge by adding it through the liquid service
port while the indoor side of the system is still under a vacuum. The
vacuum that is on the indoor side of the system will allow you to add
most of the charge adder. If you are not able to add the full amount
then add the remainder after starting up the system to verify proper
subcooling. The subcooling charging method is explained further in
this section.
3. Release the refrigerant charge from the outdoor unit into the system.
Open both the liquid and vapor service valves at outdoor unit by
removing the plunger cap and with an allen wrench back out coun-
ter-clockwise until valve stem just touches the chamfered retaining
wall. ”PRECAUTIONS DURING BRAZING SERVICE VALVE”.
4. Replace plunger cap finger tight, then tighten an additional 1/12 turn
(1/2 hex flat). Cap must be replaced to prevent leaks.
5. Use the following subcooling charging method whenever additional
refrigerant is required for the system charge. A superheat charging
method is not suitable for TXV equipped systems.
Measurement Method
If a calibrated charging cylinder or accurate weighing device is avail-
able, add refrigerant accordingly.
Subcooling Charging Method
This condensing unit must only be used with the matching thermostatic
expansion valve kit listed in the Tabular Data Sheet. This unit
must
be
charged during
cooling single stage operation (Y1), second-stage
(Y1 & Y2)
operation only
.
Charging should be matched per the
subcooling chart located on the rating plate.
1. Set the system running in the
cooling (Y1) or second-stage (Y1 &
Y2)
cooling mode by setting the thermostat at least 6°F below the
room temperature.
2. Operate the system for a minimum of 15-20 minutes.
3. Refer to the Tech Guide for the recommended airflow and verify
thisindoor airflow (it should be about 400 SCFM per ton).
4. Measure the liquid refrigerant pressure P and temperature T at the
service valve.
5. Calculate the saturated liquid temperature ST from Table 1 "R-410A
Saturation Properties".
6. Subcooling temperature TC = Saturated Temperature (ST) - Liquid
Temp (T).
Add charge if the calculated subcooling temperature TC in Step 6 is
lower than the recommended level. Remove and recover the refrigerant
if the subcooling TC is higher than the recommended level. See Table 1
for R-410A saturation temperatures.
After disconnecting manifold gauge set check flare caps on service
ports to be sure they are leak tight. DO NOT OVERTIGHTEN (between
40 and 60 inch - lbs. maximum).
The “Total System Charge” must be permanently stamped on the unit
data plate.
Total system charge is determined as follows:
1. Determine outdoor unit charge from tabular data sheet.
2. Determine indoor coil adjustment from tabular data sheet.
3. Calculate the line charge using the tabular data sheet if line length is
greater than 15 feet.
4. Total system charge = item 1 + item 2 + item 3.
5. Permanently stamp the unit data plate with the total amount of refrig-
erant in the system.
SECTION VII: INSTRUCTING THE OWNER
Assist owner with processing warranty cards and/or online registration.
Review Owners Manual, provide a copy to the owner, and provide guid-
ance on proper operation and maintenance. Instruct the owner or the
operator how to start, stop, and adjust temperature setting.
The installer should also instruct the owner on proper operation and
maintenance of all other system components.
MAINTENANCE
1. Dirt should not be allowed to accumulate on the outdoor coils or
other parts in the air circuit. Clean as often as necessary to keep
the unit clean. Use a brush, vacuum cleaner attachment, or other
suitable means.
2. The outdoor fan motor is permanently lubricated and does not
require periodic oiling.
Refrigerant charging should only be carried out by a qualified air
conditioning contractor.
R-410A refrigerant cylinders are rose colored, and have a dip tube
which allows liquid to flow out of the cylinder in the Upright Posi-
tion. Always charge the system slowly with the tank in the upright
position.
DO NOT attempt to pump “Total System Charge” into outdoor unit
for maintenance, service, etc. This may cause damage to the com-
pressor and/or other components. the outdoor unit only has enough
volume for the factory charge, not the “Total System Charge”.
Compressor damage will occur if system is improperly charged. On
new system installations, charge system per tabular data sheet for
the matched coil and follow guidelines in this instruction.
Example: The pressure P and temperature T measured at the liquid
service port is 360 Psig and 93°F. From Table 1, the saturated tem-
perature for 360 Psig is 109°. The subcooling temperature TC =
109°-93°=16°F