Document jy3y8G65aw21DL6xK4oNmaLLy

566 CHAPTER 25 1951 Guide condensate from the cooling coil is sprayed over the condenser. surface and vaporized, thus eliminating the need for drain connections. A simple (tampering arrangement is generally provided for exhausting some air from the room, in addition to introducing outside air and recirculating required amounts of air. It is possible to remove the equipment for winter storage or utilize the ventilating features for winter operation. Controls for Room Cooling Units , Control devices provided for self-contained cooling units, generally will include all necessary means for automatic operation. Provision is also made for adding auxiliary external controls, when desired. Remote units are not generally equipped with controls. Control systems for remote units, and auxiliary controls for self-contained units, are covered in the general treatment of Controls in Chapter 38. Fiq. 7. Sblf-Containrd Aib-Coolhd Unit Aib Conditionbr RATINGS OF UNIT AIR CONDITIONERS There are two codes governing the rating and testing of unit air con ditioners. The first code, Standard Method of Rating and Testing Air Conditioning Equipment,1 covers all types of air conditioning units except the self-contained type. The latter is covered by the second code, The Standard Method of Rating and Testing Self-Contained Air Conditioning, Units for Comfort Cooling.* ' The two codes are necessary because of the basic difference caused by the heat given up by the self-contained units. The standard rating conditions for self-contained unit air conditioners, as given in the code, are set forth in Table 1. The standard rating of a self-contained unit for the conditions specified in Table 1, includes all items which apply to the function of a unit as: (1) name of unit, (2) functions which unit performs, (3) data on cooling, (4) data on heating, (5) data on air flow, and (6) data on humidification. The standard rating conditions for unit air conditioners, other than the self-contained type, are identical with those in Table 1, except that entering wet-bulb temperature for cooling is expressed as 50 percent relative humidity (66.7 F wet-bulb) instead of 67 F wet-bulb temperature. In Unit Air Conditioners.and Unit Air Coolers 567 addition, the saturated suction refrigerant temperature for comfort cooling is specified at 40 F. This condition is omitted from Table 1 for self-contained units because it is immaterial in the rating of a unit that in cludes the evaporator and condensing unit. Table 1. Standard Rating Basib for Self-Contained Air Conditioning Units Types of Units Item Rating Condition Description Value All All a Barometric Pressure 29192 in. Hg. Cooling b Unit Ambient and Air Entering Water-Cooled, Room--Air Inlet Air-Cooled (1) Dry-Bulb 80 F and Evapora- (2) Wet-Bulb 67 F tively- Cooled Condensers c Ventilation Air See Note Water-Cooled Condensers d Water Temperature Entering Unit e Water Temperature Leaving Unit 75 F 95 F Air-Cooled r Air Entering Outside Air Inlet and Evapora- (1) Dry-Bulb tively-Cooled (2) Wet-Bulb Condensers 95 F 75 F Heating e Unit Ambient and Total Air Enter ing Unit 70 F All Types Provided h Heating Medium, Pressure 'or with Heating Temperature Function (1) Dry Saturated Steam 16.7 lb per sq in. ate (2) Water In 180 F (3) Water Out 160 F All Types i Unit Ambient Provided with Humidifying Humidifying j Total Air Entering Unit Function (1) Dry-Bulb (2) Wet-Bulb 70 F 70 F. 63 F Air Circulation All k Filters New and Clean Batins shall bo based on both ventilation and ndroulatod room air enteritis at 80 F dry-bulb and 67 F wet-bulb temperature. (The teruu not pertinent to chapter). Vote as liven in the code has been condensed in order to remove ma- APPLICATION OF UNITARY EQUIPMENT One of the chief advantages resulting from use of factory produced units is the saving in installation and field assembly labor, a factor that should always be kept in mind when selecting a location for these units.' Because of their compactness, the tendency exists to put them in closets, storage rooms, and other inaccessible places, where installation is so difficult that much of this cost advantage is lost. Access panels are provided on units for the proper servicing and main tenance of the equipment. Adequate outside clearance at' these panels is