Carrier 50ZHA024-060 Deduct 10 percent for 208 Volt Operation, UnitControls, Sequenceof Operation

Table 7—Dry Coil Air Delivery* Horizontal Discharge

(Deduct 10 percent for 208 Volt Operation)

50ZHA	SPEED TAP	WATTS/C.F.M				EXTERNAL STATIC PRESSURE
			0.1	0.2	.03	0.4	0.5	0.6	0.7	0.8	0.9	1.0
	1	Watts	-	99	100	118	130	142	-	-	-	-
024		C.F.M.	-	848	793	757	698	632	-	-	-	-
	2	Watts	-	-	-	-	-	222	233	244	257	260
		C.F.M	-	-	-	-	-	970	918	861	795	729
	2	Watts	-	155	146	157	170	-	-	-	-	-
030		C.F.M	-	1108	995	951	884	-	-	-	-	-
	3	Watts	-	-	-	-	-	261	275	286	291	315
		C.F.M.	-	-	-	-	-	1117	1053	1014	980	877
	1	Watts	180	166	179	191	204	216	-	-	-	-
036		C.F.M.	1344	1215	1172	1136	1095	1051	-	-	-	-
	2	Watts	-	-	-	261	276	290	301	316	329	342
		C.F.M.	-	-	-	1343	1304	1272	1234	1190	1148	1100
	3	Watts	269	283	305	321	336	349	360	-	-	-
042		C.F.M.	1440	1404	1369	1333	1301	1273	1239	-	-	-
	4	Watts	-	-	418	432	450	465	480	490	503	518
		C.F.M.	-	-	1572	1543	1504	1475	1441	1418	1380	1332
	1	Watts	—	204	209	216	229	236	249	—	—	—
		C.F.M.	—	1129	1087	1027	994	932	881	—	—	—
	2	Watts	—	—	233	245	254	266	276	289	—	—
048		C.F.M.	—	—	1164	1122	1066	1025	954	906	—	—
	3	Watts	386	398	409	418	425	435	438	441	451	—
		C.F.M.	1680	1652	1625	1583	1555	1515	1477	1444	1403	—
	4	Watts	—	440	448	457	462	469	477	480	485	486
		C.F.M.	—	1745	1717	1684	1651	1612	1573	1537	1508	1470
	1	Watts	224	235	251	266	277	291	298	-	-	-
		C.F.M.	1334	1288	1259	1224	1181	1157	1117	-	-	-
	2	Watts	-	-	286	301	311	325	333	344	370	-
060		C.F.M.	-	-	1333	1296	1261	1232	1199	1170	1062	-
	3	Watts	608	626	643	660	668	685	697	-	-	-
		C.F.M.	1931	1900	1878	1844	1817	1789	1755	-	-	-
	4	Watts	737	755	770	787	799	817	826	812	782	-
		C.F.M.	2093	2061	2028	2001	1971	1934	1899	1850	1757	-

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		HIGH AIRFLOW
SIZE	Low	High	Low	High
	Stage	Stage	Stage	Stage
048	Tap 1	Tap 3	Tap 2	Tap 4
060	Tap 1	Tap 3	Tap 2	Tap 4

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.

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.

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