Lennox ELP090S4S Installation Instructions Manual page 10

2 - Approach temperature should be as indicated in
table 3 for each stage. An approach temperature
greater than this value indicates an undercharge.
An approach temperature less than this value
indicates an overcharge.
A - Add or remove charge in increments.
B - Allow system to stabilize at least 5 minutes each
time refrigerant is added or removed.
3 - Do not use the approach method if system pressures
do not match pressures in table 4 except when the
outdoor ambient temperature is below 65ºF (18ºC).
The approach method is not valid for grossly over or
undercharged systems.
TABLE 4. HFC-410A Normal Operating Pressures – Cooling Mode (Liquid ±10 and Suction ±5 psig)**
Temp*
65º F (18º C)
75º F (24º C)
85º F (29º C)
95º F (35º C)
105º F (41º C)
115º F (46º C)
125º F (52º C)
STD. CFM
*Temperature of air entering outdoor coil.
Liquid and suction pressures measured via condenser service valve ports.
** Indoor conditions – 80° F Dry Bulb and 67° F Wet Bulb.
TABLE 5. HFC-410A Normal Operating Pressures – Heating Mode (Liquid ±10 and Suction ±5 psig)**
Temp*
60º F (15º C)
50º F (10º C)
40º F (4º C)
30º F (-1º C)
20º F (-6º C)
10º F (-12º C)
STD. CFM
*Temperature of air entering outdoor coil.
Liquid and suction pressures measured via condenser service valve ports.
** Indoor conditions – 70° F.
ELP090 / ELA090
Liquid Suction
226
261
303
349
404
462
525
2760
ELP090 / ELA090
Liquid Suction
364
343
324
311
297
280
2760
Page 10
TABLE 3. HFC-410A Approach Temperatures*
Models
ELP090S4S /
ELA090
ELP120S4S /
ELA120
*Approach temperature method valid at full load.
Liquid
119
125
129
133
135
137
136
Liquid
121
100
83
72
57
44
Approach Approach
Temperature (ºF) Temperature (ºC)
(+/-1)
7.0
6.0
ELP120 / ELA120
Suction
247 132
291 136
333 138
370 140
437 142
495 144
562 146
4000
ELP120 / ELA120
Suction
335 115
322 101
308
294
280
266
4000
(+/-.05)
3.9
3.3
86
72
58
44