For 208/230-V; Unit Controls; High-Pressure Relief Valve; Loss Of Charge Switch - Carrier 50ZHA024-060 Installation & Service Instructions Manual

50ZHA SPEED TAP
1
024
2
2
030
3
1
036
2
3
042
4
1
2
048
3
4
1
2
060
3
4
Air delivery values are based on operating voltage of 230-v., dry coil, without filter or electric heater. Deduct wet coil, filter, and electric heater pressure drops to obtain
external static pressure availabe for ducting.
Do not operate the unit at a cooling airflow that is less than 350 cfm for each 12,000 Btuh of rated cooling capacity. Evaporator coil frosting may occur at airflows below
this point.
Dashes indicate portions of the table that are beyond the blower motor capacity or are not recommended.
RATED AIRFLOW
SIZE
Low
Stage Stage
048 Tap 1 Tap 3
060 Tap 1 Tap 3
Step 5—Unit Controls
All compressors have the following internal-protection controls.

HIGH-PRESSURE RELIEF VALVE

This valve opens when the pressure differential between the low
and high side becomes excessive.

LOSS OF CHARGE SWITCH

Located on the outdoor liquid line is a low-pressure switch which
functions as a loss-of-charge switch. This switch contains a
Schrader core depressor. This switch opens at 7 psig and closes at
22 psig. No adjustment is necessary.

COMPRESSOR OVERLOAD

This overload interrupts power to the compressor when either the
current or internal temperature become excessive, and automati-
cally resets when the internal temperature drops to a safe level.
Table 7—Dry Coil Air Delivery* Horizontal Discharge
(Deduct 10 percent for 208 Volt Operation)
WATTS/C.F.M
0.1 0.2
Watts - 99
C.F.M. - 848
Watts - -
C.F.M - -
Watts - 155
C.F.M - 1108
Watts - -
C.F.M. - -
Watts 180 166
C.F.M. 1344 1215
Watts - -
C.F.M. - -
Watts 269 283
C.F.M. 1440 1404
Watts - -
C.F.M. - -
Watts — 204
C.F.M. — 1129
Watts — —
C.F.M. — —
Watts 386 398
C.F.M. 1680 1652
Watts — 440
C.F.M. — 1745
Watts 224 235
C.F.M. 1334 1288
Watts - -
C.F.M. - -
Watts 608 626
C.F.M. 1931 1900
Watts 737 755
C.F.M. 2093 2061
HIGH AIRFLOW
High Low High
Stage Stage
Tap 2 Tap 4
Tap 2 Tap 4
EXTERNAL STATIC PRESSURE
.03 0.4 0.5 0.6
100 118 130 142
793 757 698 632
- - - 222
- - - 970
146 157 170 -
995 951 884 -
- - - 261
- - - 1117
179 191 204 216
1172 1136 1095 1051
- 261 276 290
- 1343 1304 1272
305 321 336 349
1369 1333 1301 1273
418 432 450 465
1572 1543 1504 1475
209 216 229 236
1087 1027 994 932
233 245 254 266
1164 1122 1066 1025
409 418 425 435
1625 1583 1555 1515
448 457 462 469
1717 1684 1651 1612
251 266 277 291
1259 1224 1181 1157
286 301 311 325
1333 1296 1261 1232
643 660 668 685
1878 1844 1817 1789
770 787 799 817
2028 2001 1971 1934
This overload may require up to 60 minutes (or longer) to reset;
therefore, if the internal overload is suspected of being open,
disconnect the electrical power to the unit and check the circuit
through the overload with an ohmmeter or continuity tester.
Step 6—Sequence of Operation

FAN OPERATION

The FAN switch on the thermostat controls indoor fan operation.
When the FAN switch is placed in the ON position, the IFR
(indoor-fan relay) is energized through the G terminal on the
thermostat. The normally-open contacts close, which then provide
power to the indoor (evaporator) fan motor (IFM). The IFM will
run continuously when the FAN switch is set to ON.
When the FAN switch is set to AUTO, the thermostat deenergizes
the IFR (provided there is not a call for cooling). The contacts open
and the IFM is deenergized. The IFM will be energized only when
there is a call for cooling, in heat pump heating mode or if the unit
is equipped with accessory electric heat, the indoor-fan motor will
also run while the accessory electric heat is energized.
NOTE: Some units are equipped with a time-delay relay. On
these units, the indoor fan remains on for 30 seconds after G or Y
is deenergized.
13
0.7 0.8 0.9 1.0
- - - -
- - - -
233 244 257 260
918 861 795 729
- - - -
- - - -
275 286 291 315
1053 1014 980 877
- - - -
- - - -
301 316 329 342
1234 1190 1148 1100
360 - - -
1239 - - -
480 490 503 518
1441 1418 1380 1332
249 — — —
881 — — —
276 289 — —
954 906 — —
438 441 451 —
1477 1444 1403 —
477 480 485 486
1573 1537 1508 1470
298 - - -
1117 - - -
333 344 370 -
1199 1170 1062 -
697 - - -
1755 - - -
826 812 782 -
1899 1850 1757 -