Carrier 50BV020-064 Evaporator Fan Performance Adjustment, Charging the System, Troubleshooting

a50-7135tf

Fig. 36 — Sheave Alignment

Evaporator Fan Performance Adjustment —

To change fan speeds from factory settings:

1.Shut off unit power supply.

2.Loosen nuts on the 4 carriage bolts in the mounting base. Using adjusting bolts and plate, slide the motor and remove the belt.

3.Loosen movable-pulley flange setscrew.

4.Screw the movable flange toward the fixed flange to increase speed, and away from the fixed flange to decrease speed. Increasing the fan speed increases the load on the motor. Do not exceed the maximum speed specified in Tables 3A and 3B.

5.Set the movable flange at nearest keyway of the pulley hub and tighten the setscrew. (See Tables 3A and 3B for speed change for each full turn of pulley flange.)

6.Replace and tighten the belts (see Belt Tension Adjust- ment section).

7.Restore power to the unit.

To align fan and motor pulleys:

1.Loosen fan pulley setscrews.

2.Slide fan pulley along fan shaft.

3.Make angular alignment by loosening motor from mounting plate.

4.Restore power to unit.

BELT TENSION ADJUSTMENT — Using a gage, apply 4 lb of force to the center of the belt and adjust the tension until a deflection of 1/64-in. is achieved for every inch of shaft center distance. See Fig. 37.

Ideal belt tension is the lowest value under which belt slip will not occur at peak load conditions.

LB FORCE

DEFLECTION

a50-7136ef

Fig. 37 — Fan Belt Tension

Charging the System

REMOTE AIR-COOLED UNITS — The 50BVE,K,U,X units are shipped with a holding charge of dry nitrogen. Remote condensers, interconnecting piping, and refrigerant to charge the system are all field supplied.

To evacuate the system, refer to GTAC II, Module 4, Dehy- dration for Proper Evacuation and Dehydration Techniques.

To charge the 50BVE,K,U,X systems:

1.Add an initial minimum refrigerant charge after evacu- ation to allow the unit to start. Refer to Tables 25A and 25B. Additional refrigerant will be added based on the length of interconnecting piping and vertical separa- tion between the indoor unit and the condenser(s).

Table 25A — Minimum Operating Charge (lb), 50BVE,K Units Matched with 09DK Condensers

UNIT SIZE		020		024		028		034
Circuit 1...	2	8.1...	8.1	9.1...	9.1	9.1...	9.1	18...	18

Table 25B — Minimum Operating Charge (lb), 50BVU,X Units Matched with 09DK Condensers

UNIT SIZE		034		044		054		064
Circuit 1...	2	18	...18	10...	10	18...	18	18...	18
Circuit 3...	4		-	10...	10	18...	18	18...	18

2.To finish charging the system, make sure the unit is running at full-load operating conditions. Charge to a clear sight glass. Refer to GTAC II, Module 5, Charging, Recovery, Recycling and Reclamation and the Refrigerant Service Techniques manual for proper charging techniques.

3.Add 10 lb of R-22 or R-410A over a clear sight glass to flood subcooler section of the condenser coils.

4.Alternately, and as a double-check, when properly charged at full-load operating conditions, there should be 15 F subcooling entering the TXV (the difference between saturated condenser temperature and actual liquid temperature entering the TXV).

Compressor Oil — All units are factory charged with oil. It is not necessary to add oil unless compressor(s) is re- moved from the unit. If necessary, oil can be removed/charged via Schrader fitting. Operate the system at high evaporator tem- perature prior to oil recharge to assist oil return to the compres- sor(s) from other system components. If necessary, recharge the system as shown in Table 26.

Table 26 — Oil Recharge

50BV			OIL	OIL	PART
	SIZE	COMPRESSOR	RECHARGE
UNIT				TYPE	NUMBER
			(oz)
	020	ZR94KC	81
C,E,	024	ZR108KC	106
Q,J,K	028	ZR144KC	106	3GS 150
	034	ZR19M3	137	viscosity
				yellow	P903-0101
	034	ZR19M3	137
				mineral
T,U,	044	ZR125KC	106	oil
V,W,X	054	ZR16M3	137
	064	ZR19M3	137

TROUBLESHOOTING

Refer to Tables 27-29 to determine the possible cause of the problem and the associated procedure necessary to correct it. See Fig. 38-47 for unit and control wiring.

51