835966-UIM-E-0814
Johnson Controls Unitary Products
7
CHARGING IN HEATING MODE
If charging in heating mode, there are two methods for charging:
Weighing in the charge is the best method for ensuring the unit per-
forms as rated. However, if a device is installed in the line set that alters
the amount of refrigerant, such as a refrigerant flow meter, then the bet-
ter method for charging is to match the liquid pressure from the heating
charging chart (if available) or heating service data (available from
wwwupgnet.com). If no such device exists in the line set, then the
method is acceptable if weighing in the charge is not an option.
If servicing a unit for low heating performance and you find that you
have to add a significant amount of charge (ex: 20-30 ounces) in order
to match the published liquid pressures, the unit will NOT be over-
charged in cooling. Heat pumps are sensitive to charge in heating, but
not in cooling.
CHARGING WITH GAUGES
Do not charge a heat pump in cooling mode with gauges or charging
charts or any other method other than weighing in the charge.
However for servicing a heat pump unit, the charging charts are an
acceptable troubleshooting method, but when the servicing is com-
pleted, the charge should be reclaimed and weighed in (to guarantee
optimal performance in heating mode). If servicing in heating mode, the
charge does not have to be reclaimed if the liquid pressures match the
published values.
Before measuring the pressures, use the method above to check the air
flow and then consult the table and match the liquid pressure to that air
flow.
Before servicing a unit, confirm that your gauges are accurate by
comparing the gauges against a calibrated pressure gauge that has
been calibrated against a national standard. If a calibrated pressure
gauge is not available, place a R-410A virgin refrigerant container in a
conditioned space long enough to come to temperature equilibrium with
the surroundings. Then measure the temperature of the air and the
pressure of the refrigerant and compare it to the following table:
:
If the gauges are correct, then measure the pressures using both
the cooling and heating charts.
SECTION VII: ELECTRICAL
CONNECTIONS
GENERAL INFORMATION & GROUNDING
Check the electrical supply to be sure that it meets the values specified
on the unit nameplate and wiring label.
Power wiring, control (low voltage) wiring, disconnect switches and over
current protection must be supplied by the installer. Wire size should be
sized per NEC requirements.
The complete connection diagram and schematic wiring label is located
on the inside surface of the unit service access panel and this instruc-
tion.
FIELD CONNECTIONS POWER WIRING
1. Install the proper size weatherproof disconnect switch outdoors and
within sight of the unit.
2. Remove the screws at the bottom of the corner cover. Slide corner
cover down and remove from unit. See Figure 5.
3. Run power wiring from the disconnect switch to the unit.
4. Remove the service access panel to gain access to the unit wiring.
Route wires from disconnect through power wiring opening provided
and into the unit control box.
5. Install the proper size time-delay fuses or circuit breaker, and make
the power supply connections.
6. Energize the crankcase heater if equipped to save time by preheat-
ing the compressor oil while the remaining installation is completed.
Refrigerant charging should only be carried out by a qualified air con-
ditioning contractor.
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.
TABLE 2:
R-410A Saturation Properties
Temp
(°F)
Pressure
(Psig)
Temp
(°F)
Pressure
(Psig)
Temp
(°F)
Pressure
(Psig)
40
119
75
218
110
365
45
130
80
236
115
391
50
143
85
255
120
418
55
156
90
274
125
447
60
170
95
295
130
477
65
185
100
317
70
201
105
341
All field wiring must USE COPPER CONDUCTORS ONLY and be in
accordance with Local, National Fire, Safety & Electrical Codes. This
unit must be grounded with a separate ground wire in accordance
with the above codes.
FIGURE 5:
Typical Field Wiring
Corner
Cover
Control
Wiring
Power
Wiring
Service
Access
Panel
Ambient
Temperature
Sensor
A0203-001
