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1945 Theatre Catalog, 4th Edition, Page 406 (382)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 406
Page 406

1945 Theatre Catalog, 4th Edition, Page 406

the terminal. Excess sparking is an indication that the contacts should be cleaned, Oftentimes the pitted surfaces andzdust are not visible. Clean with care, by using a fine sandpaper on the two terminals which form the contact.

Couplings ancl Unions

When fan, compressor, or pumps are not belt-driven, nor the fan mounted on the motor shaft, couplings are used to connect the motor drive to the rotating part. The coupling may be identihed as the disc-like part located between the motor shaft and fan, compressor, or pump shaft. These discelike parts are bolted together so that the two shafts will operate as a unit.

Unions are metal-to-metal seat unions with conical or spherical joints, having at least one face made from brass. In addition to the ordinary pattern, they may be made in special forms, such as elbows, tees, and so forth. They are designed for use where the working pressures do not exceed 50 pounds to the square inch.

Check line-up of couplings and unions at least once a year, according to the owners operating instructions. Where a coupling seems out of line, that is, the shafts do not continue as one piece, consult your maintenance man. '


Dampers are used for regulating the amount of air in the system. They are automatically or manually operated. Bearings and linkages, connecting the damper levers to controls, should be kept oiled so that they will move freely. Automatically operated dampers should be checked for easy operation. Dampers should not be allowed to rust, and should

THE DUCT SYSTEM of an air-conditioning installation must be kept free from dust and lint which not only prevents.

be painted often to prevent such deterioration.

Ducts and Duct Systems

Ducts compose the air distributing system, when air-conditiioning equipment is located remotely from the room being conditioned. Two precautions should be taken in servicing ducts: one is guarding against the collecting of dust and lint and the other the prevention of opening up joints, permitting large quantities of conditioned air to escape. Check all ducts for opened joints and tighten wherever possible. Ducts should be cleaned out at intervals, so that dust and lint will not accumulate and restrict the How of air within. Cleaning of ducts is also a precaution against fire. To prevent ducts from rusting, refer to Metals for the care of sheet metal.

Fans and Blowers

Fans, included in all air-conditioning systems, may be either the propellor or the multiblade, centrifugal type. Sources of noise in fan system, include (1) improper balance of the moving parts, (2) excessive speeds of fans not properly selected, (3) pulsations due to fans too large for the system, (4) high-frequency hum from electric motors, (5) air noises from imperfectly designed or insulated ducts, and (6) lack of insulation. These faults should be corrected.

Fans, like all moving parts, require periodic attention to keep the maintenance low and to insure long life of the fan. To care for fans, follow the instructions given under Bearings, Belts, and Metals. With fans of the propellor type, clean the blades when they are accessible without removing parts of the unit. Centrifugal fans do not have

the proper operation of dampers and vents but also forms a tirevhazard. Shown here is part of the duct system Installed in a large California theatre. Besides maintaining the ducts free from matter which might cause clogging, it is also necessary to maintain exterior surfaces for the prevention of rust. Follow the instructions.


easily accessible blades, so require a trained service engineer for a cleaning job. To avoid excess wear, fan and fan motor bearingsshould'be iubricated regularly, using the Oil or grease recommended by the manufacturer.


In most air-conditioning, refrigeration, and heating systems, the pulley for runing the equipment (notthe motor pulley) is built to serve as a ,tiywheel. Therefore, in most instances, checking on the pulley means checking on the flywheel. Keep fiywheel running true. A wobbly fiywheel, or pulley, causes unnecessary shaft and belt wear and excessive vibration. If the wheel becomes wobbly, call your maintenance man. Keep the screw tight, so that the dywheel, or pulley, is held in place.


Fuses and motor-overload protectors must be of the right size and type to protect motors against overheating and possible burn-out. If the fuses are oversize, they will not protect the motor; if undersize, they may blow and stop the motor needlessly. Fuses should not be of the delayed-action type. It always pays to have these devices checked by your Serviceman or electrician. All motor fuses should be of the proper size, as specified by the underwriters. Also, fuses should be tested for tightness, contacts, and cleanliness of contact surfaces. The links in the fuses should be replaced about every one or two years, as it is not always wise to wait for a fuse to blow before replacing the links.


Various gauges are put on air-conditioning and refrigeration equipment to show how the equipment is operating. They are of value only when they are recording properly. Mark on the gauge the place the indicating needle should be when the equipment is operating correctly, according to the instructions supplied at the time of installation. When the gauges are not operating, call your maintenance man.

Grilles and Air Outlets

Stopped-up grilles, air outlets, and louvers cut down the how of air and lessen the efiiciency of the entire system. When cleaning this equipment, he careful not to change the adjustment of the outlets or dampers.


Leaks in air-conditioning, refrigeration, and heating equipment mean waste. To save, prevent these leaks when possible by proper care, and repair all leaks promptly. Leaks in water lines are detected by drips, those in steam lines by presence of moisture. Usually leaks can be repaired by an unskilled, but instructed mechanic.


A large amount of metal is used in air-conditioning, refrigeration, heating, and ventilation equipment, so its protection is an important part of maintenance.

1945 Theatre Catalog, 4th Edition, Page 406