Lennox KCC Series Unit Information page 33

B-Refrigerant Charge and Check - Fin/Tube Coil
WARNING - Do not exceed nameplate charge under
any condition.
This unit is factory charged and should require no further
adjustment. If the system requires additional refrigerant,
reclaim the charge, evacuate the system, and add required
nameplate charge.
NOTE - System charging is not recommended below 60°F
(15°C). In temperatures below 60°F (15°C) , the charge
must be weighed into the system.
If weighing facilities are not available, or to check the
charge, use the following procedure:
IMPORTANT - Charge unit in standard cooling mode.
1 - Attach gauge manifolds and operate unit in cool-
ing mode with economizer disabled until system
stabilizes (approximately five minutes). Make sure
outdoor air dampers are closed.
2 - Check each system separately with all stages
operating.
3 - Use a thermometer to accurately measure the out-
door ambient temperature.
4 - Apply the outdoor temperature to TABLE 10 to
TABLE 13 to determine normal operating pressures.
Pressures are listed for sea level applications at
80°F dry bulb and 67°F wet bulb return air.
5 - Compare the normal operating pressures to the
pressures obtained from the gauges. Minor varia-
tions 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. Correct any system problems before
proceeding.
6 - If discharge pressure is high, remove refrigerant
from the system. If discharge pressure is low, add
refrigerant to the system.
• Add or remove charge in increments.
• Allow the system to stabilize each time refriger-
ant is added or removed.
7 - Use the following approach method along with the
normal operating pressures to confirm readings.
TABLE 10 581129-01
KGC/KCC092S Fin/Tube - W & W/O Reheat
Outdoor CIRCUIT 1
Coil
Discharge
Entering
+ 10 psig
Air Temp
65°F 270
75°F 310
85°F 352
95°F 401
105°F 453
115°F 511
CIRCUIT 2
Suction Discharge Suction
+ 5 psig + 10 psig + 5 psig
128 255
131 295
133 338
136 388
140 433
145 488
KGC/KCC102S Fin/Tube - W & W/O Reheat
Outdoor
Coil
Entering
Air Temp
65°F
75°F
85°F
95°F
105°F
115°F
KGC/KCC120S Fin/Tube - W & W/O Reheat
Outdoor
Coil
Entering
Air Temp
65°F
75°F
85°F
95°F
105°F
115°F
KGC/KCC150S Fin/Tube - W & W/O Reheat
Outdoor
Coil
Entering
Air Temp
65°F
75°F
85°F
95°F
105°F
115 °F
Charge Verification - Approach Method - AHRI Testing
(Fin/Tube Coil Continued)
1 - Using the same thermometer, compare liquid tem-
perature to outdoor ambient temperature.
Approach Temperature = Liquid temperature (at
condenser outlet) minus ambient temperature.
2 - Approach temperature should match values in
TABLE 14. An approach temperature greater than
value shown indicates an undercharge. An approach
temperature less than value shown indicates an
overcharge.
140
3 - The approach method is not valid for grossly over
146
or undercharged systems. Use TABLE 10 to TABLE
151
13 as a guide for typical operating pressures.
155
160
162
Page 33
TABLE 11 581130-01
CIRCUIT 1
Discharge Suction Discharge
+ 10 psig + 5 psig + 10 psig
269 128
308 132
350 135
396 139
447 141
502 146
TABLE 12 581131-01
CIRCUIT 1
Discharge Suction + Discharge
+ 10 psig 5 psig + 10 psig
263 125
301 125
341 123
386 125
440 130
492 139
TABLE 13 581132-01
CIRCUIT 1
Discharge Suction + Discharge
+ 10 psig 5 psig + 10 psig
281 121
320 125
364 129
407 132
456 135
508 139
CIRCUIT 2
Suction
+ 5 psig
276 138
314 142
359 146
407 149
458 152
513 156
CIRCUIT 2
Suction +
5 psig
262 132
304 140
348 146
394 152
447 156
499 158
CIRCUIT 2
Suction +
5 psig
283 137
325 141
370 143
415 145
464 148
517 151