Lennox Elite XC16 Installation Instructions Manual page 19

START: Measure outdoor ambient temperature
USE WEIGH-IN METHOD
DO NOT CHARGE UNIT
Weigh-in or remove refrigerant
(Results of charging at low
based upon line length
temperatures not reliable)
If refrigerant is added
or removed, retest to
confirm that unit is
properly charged.
If value is greater than shown (high approach),
add refrigerant; if less than shown (liquid
temperature too close to ambient temperature,
low approach), remove refrigerant.
Table 2. Normal Operating Pressures In PSIG (Liquid +/− 10 and Suction+/− 5 PSIG)
IMPORTANT
Temp. of air
−024
entering
outdoor coil
5F (5C)
Liquid
65 (18.3) 215
75 (23.9) 247
85 (29.4) 288
95 (35.0) 332
105 (40.6) 381
115 (46.1) 435
65 (18.3) 225
75 (23.9) 258
85 (29.4) 301
95 (35.0) 346
105 (40.6) 397
115 (46.1) 452
*These are typical pressures only. Indoor indoor match up, indoor air quality, and indoor load will cause the pressures to vary.
ABOVE or
BELOW
64ºF and
BELOW
Figure 32. Approach TXV Charge
Use this table to perform maintenance checks; it is not a procedure for
charging the system. Minor variations in these pressures may be 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.
−036
Suction Liquid
First Stage (Low Capacity)
144 226
146 261
148 304
151 352
153 405
155 460
Second Stage (High Capacity)
140 228
142 262
144 306
146 353
149 405
151 462
1. Confirm proper airflow across coil using figure
65ºF
2. Compare unit pressures with Table 2, Normal
and
ABOVE
3. Set thermostat to call for heat (must have a
4. Connect gauge set.
5. When heat demand is satisfied, set thermostat
6. Allow temperatures and pressures to stabilize.
7. Record outdoor ambient temperature:
8. Record liquid line temperature:
9. Subtract to determine approach (APPº):
10. Compare results with table below.
APPº (Approach) Values(F:+/−1.0° [C: +/−0.6°])
Second Stage (High Capacity)
Models
ºF (ºC)* −024 −036
Any 6 (3.3) 6 (3.3)
*Temperature of air entering outdoor coil
Second Stage (High Capacity)
−048
Suction Liquid
142 224
144 258
145 299
147 345
150 395
150 450
144 235
146 269
148 313
150 361
151 412
154 471
Page 19
28.
Operating Pressures − Second Stage (High
Capacity).
cooling load between 70-80ºF (21−26ºC).
to call for second stage (high capacity) cooling.
AMBº =_________
LIQº = __________
LIQº_____ − AMBº _____ = APPº_____
−048 −060
8 (4.4) 4 (2.2)
*
−060
Suction Liquid
142 215
144 250
146 291
148 337
150 388
153 444
135 220
137 256
139 299
141 347
143 402
146 462
Suction
136
139
142
144
146
148
130
133
136
138
141
143
XC16 SERIES