System Performance - Lennox 12CHP060 Installation Instructions Manual

Unit must be grounded with separate ground conductor.
The unit wiring diagram is located inside the unit access
panel. Low voltage control wiring are pigtail leads located
below the main control box and are color coded to match
the connection called out on the wiring schematic.
If any of the original unit wiring is replaced, the same size
and type wire must be used. Electrical wiring must be
sized to carry minimum circuit ampacity marked on the
unit. Each unit must be wired with a separate branch cir
cuit and be properly fused.

System Performance

For maximum performance of this heat pump system, the
operating temperatures and pressures should be
checked and superheat determined at Standard ARI test
conditions of 82_F outdoor − 80_F indoor dry bulb/67_F
wet bulb. If superheat measured deviates from values in
table below, refrigerant charge should be adjusted ac
cordingly for maximum performance.
Verify system performance using table 3 or table 4 as a
70°F db RETURN AIR
MODEL PRESSURE
12CHP−024
12CHP−030
12CHP−036
SUCTION SUCTION
12CHP−042
12CHP−048
12CHP−060
12CHP−024
12CHP−030
12CHP−036
LIQUID LIQUID
12CHP−042
12CHP−048
12CHP−060
TABLE 3
NORMAL OPERATING PRESSURES −− HEATING MODE
AIR TEMPERATURE ENTERING OUTDOOR COIL (°F)
0° 5° 10° 15°
17 20 24 28
14 17 21 25
14 17 21 25
16 19 23 27
15 18 22 26
14 17 21 25
181 191 200 209
168 173 179 184
165 172 178 184
167 174 181 187
203 211 220 229
163 170 177 183
general guide. These tables should not be used for charg
ing the unit. Minor variations in these pressures may be
expected due to differences in installations. Significant
differences could mean that the system is not properly
charged or that a problem exists with some component in
the system. Used carefully, this table could serve as a use
ful service guide. Table 3 should be used when unit is
charged during the heating mode. If outdoor ambient is
below 45°F, run unit through defrost cycle first, wait 15
minutes for system pressures to stabilize, then take pres
sures. Data in table 3 is based on 70°F dry bulb return air.
Data in table 4 is based on 80°F dry bulb / 67°F wet bulb
return air. Allow unit operation to stabilize before taking
pressure readings.
SUCTION SUPERHEAT TABLE
UNIT MODEL NO.
12CHP−030, −036
12CHP−024
12CHP−030
12CHP−036
12CHP−042, −048, −060
20° 25° 30° 35°
33 38 43
29 34 39
29 34 39
31 36 41
30 35 40
29 34 39
219 228 237 247
189 195 200 205
191 197 203 210
194 201 207 214
237 246 255 263
190 197 203 210
Page 8
TABLE 2
SUCTION SUPERHEAT
82_F OD minus 80_F IDDB
/ 67_F IDWB
18 − 20_ 18 20
40° 45° 50°
49 55 62 69
45 51 56 63
45 51 56 63
45 51 55 62
45 51 55 62
44 50 54 61
256 265 275
211 216 221
216 222 229
221 227 234
272 281 289
217 223 230
55° 60°
74 81
70 78
70 78
68 76
68 76
67 75
284 293
227 232
235 241
241 247
298 307
237 243