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506636−01
Table 4. Normal Operating Pressures (10 and S5 psig)
IMPORTANT
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.
Model
−018
−024
−030
−036
−041
−042
−047
−048
−060
**Temp.
5
F (
5
C)
Liquid /
Suction
Liquid /
Suction
Liquid /
Suction
Liquid /
Suction
Liquid /
Suction
Liquid /
Suction
Liquid /
Suction
Liquid /
Suction
Liquid /
Suction
Expansion Valve (TXV)
65 (18)
230 / 138
225 / 135
226 / 129
238 / 132
233 / 142
236 / 138
233 / 139
238 / 136
239 / 133
70 (21)
244 / 139
242 / 137
241 / 131
254 / 135
239 / 142
253 / 140
252 / 140
256 / 138
258 / 135
75 (24)
265 / 140
260 / 138
259 / 134
273 / 138
256 / 143
273 / 141
272 / 141
277 / 139
278 / 136
80 (27)
286 / 140
282 / 140
281 / 138
293 / 140
278 / 144
296 / 142
294 / 142
299 / 140
300 / 137
85 (29)
307 / 142
304 / 141
301 / 140
316 / 142
299 / 145
318 / 143
315 / 142
320 / 139
323 / 138
90 (32)
330 / 143
326 / 142
324 / 141
340 / 143
321 / 145
341 / 144
338 / 144
343 / 140
346 / 139
95 (35)
351 / 144
351 / 142
348 / 142
366 / 144
343 / 146
366 / 146
361 / 144
369 / 141
370 / 140
100 (38)
380 / 144
376 / 144
372 / 143
392 / 145
366 / 147
392 / 147
387 / 144
395 / 142
396 / 142
105 (41)
407 / 145
403 / 145
399 / 144
420 / 147
389 / 148
417 / 148
413 / 145
422 / 144
415 / 143
110 (43)
436 / 146
433 / 145
428 / 145
449 / 148
421 / 149
445 / 149
442 / 148
450 / 146
449 / 145
115 (45)
466 / 147
463 / 147
456 / 146
480 / 149
452 / 151
475 / 151
465 / 148
481 / 148
476 / 147
Fixed Orifice (RFC)
65 (18)
232 / 124
228 / 125
229 / 128
241 / 131
228 / 131
248 / 135
232 / 125
240 / 126
244 / 125
70 (21)
248 / 127
244 / 127
243 / 129
258 / 134
245 / 135
266 / 138
249 / 129
260 / 129
263 / 128
75 (24)
267 / 131
261 / 131
261 / 132
277 / 136
263 / 138
285 / 141
268 / 133
281 / 133
281 / 131
80 (27)
286 / 135
284 / 134
284 / 135
298 / 139
284 / 141
305 / 143
286 / 136
301 / 135
303 / 134
85 (29)
307 / 138
303 / 137
305 / 138
321 / 141
306 / 144
327 / 145
312 / 140
324 / 138
324 / 136
90 (32)
328 / 141
325 / 140
327 / 140
342 / 143
327 / 146
349 / 147
332 / 142
346 / 140
347 / 139
95 (35)
351 / 143
347 / 142
349 / 142
366 / 145
348 / 148
372 / 149
357 / 144
371 / 142
370 / 141
100 (38)
375 / 146
370 / 144
372 / 144
392 / 147
372 / 149
396 / 150
379 / 146
395 / 144
394 / 143
105 (41)
400 / 148
394 / 146
396 / 146
416 / 149
395 / 151
421 / 152
406 / 149
420 / 146
418 / 145
110 (43)
426 / 150
420 / 148
422 / 148
446 / 151
424 /153
447 / 153
430 / 150
447 / 148
444 / 146
115 (46)
457 / 153
447 / 150
449 / 150
480 / 152
453 / 155
476 / 154
460 / 152
473 / 150
471 / 147
*Values shown are typical pressures; indoor unit match up, indoor air quality equipment, and indoor load will cause the pressures to vary.
**Temperature of the air entering the outside coil.
System Operation
UNIT COMPONENTS
High Pressure Switch (S4)
XC14 units are equipped with a high-pressure switch that
is located in the liquid line of the compressor as illustrated
in
Unit Dimensions
on page 2. The switch is a Single Pole,
Single Throw (SPST), manual−reset switch with red cap
that is normally closed and removes power from the
compressor when discharge pressure rises above factory
setting at 590 + 10 psi.
Thermal Protection Switch (S5) Discharge Line
Mounted
This unit is equipped with a discharge line mounted
temperature switch that prevents compressor damage
due to loss of charge. The switch is located on the
discharge line (see figure 1 for location). When the switch
senses a discharge line temperature of 220°F +/−5°F, it
opens to shut off compressor operation. The auto−reset
switch closes when the discharge line temperature drops
below 180°F +/−9°F and the compressor is re−energized.
This single−pole, single−throw (SPST) bi−metallic switch is
wired in series with the 24V Y input signal to control
compressor operation.
Thermal Protection Switch (S173) Compressor
Mounted
Some units are equipped with a compressor mounted
normally closed temperature switch that prevents
compressor damage due to overheating caused by
internal friction. The switch is located on top of the
compressor casing (see figure 1). This switch senses the
compressor casing temperature and opens at 239−257°F
(115°C−125°C) to shut off compressor operation. The
auto−reset switch closes when the compressor casing
temperature falls to 151−187°F (66°C−86°C), and the
compressor is re−energized. This single−pole, single−throw
(SPST) bi−metallic switch is wired in series with the 24V Y
input signal to control compressor operation.
Crankcase Thermostat (S40) (−041, −047, −048 and
−060 units only)
Compressor in the above reference units are equipped
with a 70 watt, belly band type crankcase heater. HR1
prevents liquid from accumulating in the compressor. HR1
is controlled by a thermostat located on the liquid line.
