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TABLE 7
Outdoor Coil
12HPB24 12HPB30 12HPB36 12HPB42 12HPB48 12HPB60
Air Entering
Temp.
_F (_C)
liq.
+
10
PSIG
vap.
+
5
PSIG
liq.
+
10
PSIG
vap.
+
5
PSIG
liq.
+
10
PSIG
vap.
+
5
PSIG
liq.
+
10
PSIG
vap.
+
5
PSIG
liq.
+
10
PSIG
vap.
+
5
PSIG
liq.
+
10
PSIG
vap.
+
5
PSIG
65 (183.) 144 78 140 76 152 74 152 75 146 75 146 73
75 (23.9) 170 79 164 77 178 76 179 76 171 77 175 74
85 (29.4) 199 80 194 78 208 77 210 77 198 78 206 75
95 (35) 228 81 224 79 238 78 241 78 229 79 237 76
105 (40.6) 261 82 259 80 275 81 278 79 268 81 275 77
NOTE − Typical pressures only. Indoor evaporator match up, indoor air quantity, and evaporator load will cause the pressures to vary.
SUBCOOLING METHOD (TXV SYSTEMS)
(Ambient Temperature Below 60_F [16_C]
NOTE- It may be necessary to restrict air flow in order to
reach liquid pressures in the 200-250 psig range which
are required for checking charge. The indoor temperature
should be above 70_F (21_C). Block equal sections of air
intake panels, moving obstructions sideways until liquid
pressures in the 200-250 psig range are reached.
1 − Connect gauge manifold. Connect an upright R−22
drum to center port of gauge manifold.
2 − Operate indoor and outdoor units in cooling mode.
Allow outdoor unit to run until system pressures sta-
bilize.
3 − Make sure thermometer well is filled with mineral oil
before checking liquid line temperature.
4 − Read liquid line pressure and convert to con-
densing temperature using temperature/pres-
sure conversion chart.
Condensing temperature (read from gauges)
should be warmer than the liquid line tempera-
ture.
5 − Place thermometer in well and read liquid line tem-
perature. Table 8 shows how much warmer the con-
densing temperature should be.
Add refrigerant to lower liquid line temperature.
Recover refrigerant to raise the liquid line tem-
perature.
6 − When unit is properly charged liquid line pres-
sures should approximate those given in table
7.
TABLE 8
Model Condensing Temp°F Warmer Than Liquid Line
12HPB24
12HPB30
12HPB42
12HPB48
12HPB60
SUBCOOLING METHOD
AMBIENT TEMPERATURE BELOW 60 _F (16 _ C)
11°F (6.1°C)
5°F (2.8°C)
4°F (2.2°C)
4°F (2.2°C)
6°F (3.3°C)
12HPB36 3°F (1.7°C)
IMPORTANT
Use table 7 as a general guide for performing mainte-
nance checks. Table 7 is not a procedure for charg-
ing the system. Minor variations in these pressures
may be expected due to differences in installations.
Significant deviations could mean that the system is
not properly charged or that a problem exists with
some component in the system. Used prudently,
table 7 could serve as a useful service guide.
E − Oil Charge
See compressor nameplate.
IV − MAINTENANCE
At the beginning of each heating or cooling season, the
system should be cleaned as follows:
A − Outdoor Unit
1 − Clean and inspect condenser coil. (Coil may be
flushed with a water hose).
NOTE − Make sure all power is disconnected before
flushing coil with water.
2 − Visually inspect all connecting lines, joints and
coils for evidence of oil leaks.
NOTE-Outdoor fan motors are permanently
lubricated.
B − Indoor Coil
1 − Clean coil if necessary.
2 − Check connecting lines and coil for evidence of oil
leaks.
3 − Check condensate line and clean if necessary.
C − Indoor Unit
1 − Clean or change filters.
2 − Bearings are pre-lubricated and need no further oil-
ing.
3 − Check all wiring for loose connections.
4 − Check for correct voltage at unit.
5 − Check amp−draw on blower motor.
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