835959-UIM-D-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 control box cover.
FIELD CONNECTIONS POWER WIRING
1. Install the proper size weatherproof disconnect switch outdoors and
within sight of the unit.
2. Remove the screws from the control box cover and remove from
unit.
3. Run power wiring from the disconnect switch to the unit.
4. Route wires from disconnect through the reversible high voltage
conduit plate and then into the unit control box shown in Figures 5.
5. Install the proper size time-delay fuses or circuit breaker, and make
the power supply contactor connections.
6. Energize the crankcase heater if equipped to save time by preheat-
ing the compressor oil while the remaining installation is completed.
FIELD CONNECTIONS CONTROL WIRING
1.
Route low voltage wiring through the snap bushing in the low volt-
age box as shown in Figure 5. Make low voltage wiring connec-
tions inside the low voltage box per Figures 6 & 7.
2.
The complete connection diagram and schematic wiring labels are
located on the inside surface of the unit control box cover.
3.
Replace the control box cover removed in Step 2 of the “Field Con-
nections Power Wiring” procedures.
4.
All field wiring to be in accordance with national electrical codes
(NEC) and/or local city codes.
5.
Mount the thermostat about 5 ft. above the floor, where it will be
exposed to normal room air circulation. Do not place it on an out-
side wall or where it is exposed to the radiant effect from exposed
glass or appliances, drafts from outside doors or supply air grilles.
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 accor-
dance with the above codes.
FIGURE 5:
Outdoor Unit Control Box
Defrost
Control
Board
Low Voltage
Box
Snap Bushing
Conduit
Plate
Ground Lug
Capacitor
Contactor
Relay
Transformer
A0195-001
