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1031452-UIM-B-0513
6 Johnson Controls Unitary Products
SUPERHEAT CHARGING METHOD -
PISTON INDOOR
1. Operate system until temperatures and pressures stabilize (mini-
mum of 10 minutes).
2. Measure and record indoor wet bulb (WB) temperature using a
sling psychrometer and the outdoor dry bulb (DB) temperature
using a thermometer.
3. Measure and record the suction pressure at the suction service
valve port.
4. Using charts located on the unit, note the superheat value corre-
sponding to the intersection of the indoor wet bulb and the outdoor
dry bulb.
5. With the superheat value obtained in step 4 and the suction pres-
sure value from step 3, find the intersection of the values on the
chart. This is the required suction tube temperature at the suction
service valve.
6. To bring the tube temperature in line with the required value from
chart, add refrigerant to the service port to cause the tube temper-
ature to fall and reclaim refrigerant to cause the temperature to
rise.
SUBCOOLING CHARGING METHOD - TXV INDOOR
The recommended subcooling is 10°F
1. Set the system running in the cooling mode by setting the thermo-
stat at least 6°F below the room temperature.
2. Operate the system for a minimum of 15-20 minutes.
3. Refer to the tabular data sheet for the recommended airflow and
verify this indoor 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 2.
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
2.
Check flare caps on service ports to be sure they are leak tight. DO
NOT OVERTIGHTEN (between 40 and 60 inch - lbs. maximum).
SECTION VIII: 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.
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 top and sides of the corner cover. Slide
corner cover down and remove from unit.
3. Run power wiring from the disconnect switch to the unit.
4. Route wires from disconnect through power wiring opening pro-
vided and into the unit control box as shown in Figure 6.
5. Install the proper size time-delay fuses or circuit breaker, and
make the power supply connections.
Example: The pressure P and temperature T measured at the liq-
uid service port is 196 psig and 90°F, respectively. From Table 2,
the saturated temperature for 196 psig is 100°F. The subcooling
temperature TC = 100°-90°=10°F
TABLE 2:
R-22 Saturated Properties
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
Pressure
PSIG
Temp °F
80 48 110 64 140 78 170 91 200 101 230 111
82 49 112 65 142 79 172 91 202 102 232 112
84 50 114 66 144 80 174 92 204 103 234 112
86 51 116 67 146 81 176 93 206 103 236 113
88 52 118 68 148 82 178 94 208 104 238 114
90 54 120 69 150 83 180 94 210 105 240 114
92 55 122 70 152 84 182 95 212 105 242 115
94 56 124 71 154 84 184 96 214 106 244 115
96 57 126 72 156 85 186 97 216 107 246 116
98 58 128 73 158 86 188 97 218 107 248 117
100 59 130 74 160 87 190 98 220 108 250 117
102 60 132 75 162 88 192 99 222 109 252 118
104 61 134 76 164 88 194 99 224 109 254 118
106 62 136 77 166 89 196 100 226 110 256 119
108 63 138 78 168 90 198 101 228 111 258 119
IT IS UNLAWFUL TO KNOWINGLY VENT, RELEASE OR DIS-
CHARGE REFRIGERANT INTO THE OPEN AIR DURING REPAIR,
SERVICE, MAINTENANCE OR THE FINAL DISPOSAL OF THIS
UNIT.
WHEN THE SYSTEM IS FUNCTIONING PROPERLY AND THE
OWNER HAS BEEN FULLY INSTRUCTED, SECURE THE
OWNER’S APPROVAL.
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.