Refrigerant Charging

PUMP PRIMING CONN.

SUCTION

PUMP

SUPPORT

GAS VENT

GLOBE

VALVES

SUPPLY

1-IN.

(25 mm)

PIPE

CONDENSER

WARNING

To prevent personal injury, wear safety glasses and gloves when handling refrigerant. Do not overcharge system — this can cause compressor flooding.

NOTE: Do not vent or depressurize unit refrigerant to atmo- sphere. Remove and recover refrigerant following accepted practices.

TANK

FINE MESH SCREEN

REMOVE WATER

REGULATING VALVE

RETURN

Air Coil Fan Motor Removal

CAUTION

Before attempting to remove fan motors or motor mounts, place a piece of plywood over evaporator coils to prevent

Fig. 23 — Forced Circulation Method

For average scale deposit, allow solution to remain in con- denser overnight. For heavy scale deposit, allow 24 hours. Drain condenser and flush with clean water. Follow acid manu- facturer’s instructions.

Compressor — Conduct annual amperage checks to in- sure that amp draw is no more than 10% greater than indicated on the serial plate data.

Fan Motors — All units have lubricated fan motors. Fan motors should never be lubricated unless obvious, dry opera- tion is suspected. Periodic maintenance oiling is not recom- mended, as it will result in dirt accumulating in the excess oil and cause eventual motor failure. Conduct annual dry opera- tion check and amperage check to ensure amp draw is no more than 10% greater than indicated on serial plate data.

Belt — Check that the belt is tight. Retighten if needed. Re- place if it is split or cracked.

Air Coil — The air coil must be cleaned to obtain maximum performance. Check once a year under normal operating condi- tions and, if dirty, brush or vacuum clean. Care must be taken not to damage the aluminum fins while cleaning.

Checking System Charge — Units are shipped with full operating charge. If recharging is necessary:

1.Insert thermometer bulb in insulating rubber sleeve on liquid line near filter drier. Use a digital thermometer for all temperature measurements. DO NOT use a mercury or dial-type thermometer.

2.Connect pressure gage to discharge line near compressor.

3.After unit conditions have stabilized, read head pressure on discharge line gage.

NOTE: Operate unit a minimum of 15 minutes before checking charge.

4.From standard field-supplied Pressure-Temperature chart for R-410A, find equivalent saturated condensing temperature.

5.Read liquid line temperature on thermometer; then subtract from saturated condensing temperature. The dif- ference equals subcooling temperature.

coil damage.

Motor power wires need to be disconnected from motor terminals before motor is removed from unit.

1.Shut off unit main power supply.

2.Loosen bolts on mounting bracket so that fan belt can be removed.

3.Loosen and remove the 2 motor mounting bracket bolts on left side of bracket.

4.Slide motor/bracket assembly to extreme right and lift out through space between fan scroll and side frame. Rest motor on a high platform such as a step ladder. Do not allow motor to hang by its power wires.

Blower Fan Sheaves — Factory-supplied drives are pre-aligned and tensioned, however, it is recommended that the belt tension and alignment be checked before starting the unit. Always check the drive alignment after adjusting belt tension. Sheave and belt information is shown in Table 17.

Each factory-assembled fan, shaft, and drive sheave assem- bly is precision aligned and balanced. If excessive unit vibration occurs after field replacement of sheaves, the unit should be rebalanced. To change the drive ratio, follow the steps in the Blower Fan Performance Adjustment section.

After 1 to 3 minutes of operation, check the belt tension. Also check tension frequently during the first 24 hours of oper- ation and adjust if necessary. Periodically check belt tension throughout the run-in period, which is normally the initial 72 hours of operation.

ALIGNMENT — Make sure that fan shafts and motor shafts are parallel and level. The most common causes of misalign- ment are nonparallel shafts and improperly located sheaves. Where shafts are not parallel, belts on one side are drawn tight- er and pull more than their share of the load. As a result, these belts wear out faster, requiring the entire set to be replaced be- fore it has given maximum service. If misalignment is in the sheave, belts enter and leave the grooves at an angle, causing excessive belt and sheave wear.

Shaft Alignment — Check shaft alignment by measuring the distance between the shafts at 3 or more locations. If the dis- tances are equal, then the shafts are parallel.

Sheave Alignment

1.To check the location of the fixed sheaves on the shafts, use a straightedge or a piece of string. If the sheaves are properly aligned, the string will touch them at the points indicated by the arrows in Fig. 24. Rotate each sheave a half revolution to determine whether the sheave is wob- bly or the drive shaft is bent. Correct any misalignment.

2.With sheaves aligned, tighten cap screws evenly and progressively.