036-21345-001-B-0105
6
Unitary Products Group
*These power requirements include the following condenser fan motor KW.
LINE SIZING
When sizing refrigerant pipe for a split-system air conditioner,
check the following:
1.
Suction line pressure drop due to friction.
2.
Liquid line pressure drop due to friction.
3.
Suction line velocity for oil return.
4.
Liquid line pressure drop due to vertical rise.
Tables 6 and 7 list friction losses for both the suction and liq-
uid lines on the condensing section. For certain piping
arrangements, different sizes of suction line pipe may have to
be used. The velocity of the refrigerant vapor must always be
great enough to carry the oil back to the compressor.
Evaporator Below Condensing Section - On a split system
where the evaporator blower is located below the condensing
section, the suction line must be sized for both pressure drop
and for oil return. Oil traps may be required on this type of
application. See Table 6.
Condensing Section Below Evaporator - When the con-
densing section is located below the evaporator blower, the
liquid line must be designed for the pressure drop due to both
friction loss and vertical rise. See Table 7. If the pressure
drop due to vertical rise and friction exceeds 40 psi, some
refrigerant will flash before it reaches the thermal expansion
valve.
Flash Gas:
1.
Increases the liquid line pressure loss due to friction
which in turn causes further flashing.
2.
Reduces the capacity of the refrigerant control device
which starves the evaporator.
3.
Erodes the seat of the refrigerant control device.
4.
Causes erratic control of the refrigerant entering the
evaporator. (See Installation Instructions for more detail.)
TABLE 5: UNIT COOLING CAPACITIES AND POWER REQUIREMENTS - CONDENSING UNIT ONLY
Model
Suction Press. & Corresponding
Temp. @ Saturation
Temperature of Air on Condenser Coil,
°
F
65
75
85
95
105
115
PSIG
°
F
MBH
KW*
MBH
KW*
MBH
KW*
MBH
KW*
MBH
KW*
MBH
KW*
HA300
61.5
68.5
76.0
84.0
35
40
45
50
258
282
308
322
22.0
22.4
22.8
23.2
247
270
294
319
23.6
24.0
24.3
24.7
236
258
280
304
25.5
25.8
26.2
26.5
225
245
266
289
27.6
28.0
28.3
28.7
213
232
253
274
30.1
30.5
30.9
31.2
202
220
239
259
33.0
33.4
33.7
34.1
HB360
61.5
68.5
76.0
84.0
35
40
45
50
316
343
371
400
26.3
26.8
27.4
28.1
301
327
354
382
28.2
28.8
29.5
30.1
385
310
337
364
30.5
31.2
31.8
32.5
269
294
319
346
33.2
33.8
34.5
35.2
253
277
302
328
36.0
36.6
37.2
37.8
237
260
284
309
39.4
39.9
40.6
41.2
HB480
61.5
68.5
76.0
84.0
35
40
45
50
423
458
494
531
33.6
34.4
35.3
36.2
404
438
473
509
36.2
37.0
37.9
38.8
384
417
451
486
39.2
40.0
40.8
41.8
364
396
429
462
42.6
43.4
44.3
45.2
344
375
406
439
46.5
47.3
48.1
49.0
324
354
384
415
50.9
51.7
52.5
53.4
HB600
61.5
68.5
76.0
84.0
35
40
45
50
514
561
610
661
39.6
40.4
41.3
42.2
492
537
584
632
42.9
43.6
44.5
45.3
470
512
556
603
46.7
47.4
48.2
49.0
447
487
529
573
51.0
51.8
52.6
53.4
425
462
502
544
56.1
56.9
57.7
58.5
402
437
474
514
61.8
62.6
63.5
64.4
Model
HA300
HB360
HB480
HB600
KW
3.4
4.3
4.3
3.8
