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Fabricante : Carrier
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Arquivo Nome : 16ja-1so.pdf
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Systems can vary from one installation to another. These systems and procedures are meant for general guidelines only. The three most common types of systems are given below. Review these systems and decide which applies to your machine. Then follow the start-stop procedure given. NOTE: If machine has been shut down for more than 2 days, follow procedures under Start-Up After Limited Shutdown or Start-Up After Extended Shutdown. In all cases below, when machine starts, the white run light will energize. When the machine stops, the light will go out after automatic dilution. Automatic Start-Stop System - Starting and stopping with this system is accomplished by an automatic controller such as a thermostat or time clock, etc. Also, an AUTO-MANUAL switch is provided so the machine can be started by-pressing machine START button with switch in MANUAL position. All auxiliary equipment is tied in with the machine control circuit and will start when the machine starts. If automatic time delay relays are provided, the machine will start after a preselected time interval. The operating engineer must make periodic checks to ensure that the machine with auxiliary equipment is operating satisfactorily. PROCEDURES 1. Place AUTO-MANUAL switch in the AUTOpo-sition for the machine to start or stop automatically. The automatic controller determines when the machine starts or stops. 2. To start fully automatic machines after limited or extended shutdown place the AUTO-MANUAL switch in MANUAL and press the START button. Then follow start-up procedures for limited or extended shutdown. Only after manual start has been completed should the AUTOMANUAL switch be placed in AUTO. NOTE: When the machine shuts down either automatically or manually, the refrigerant and solution pumps will continue to run until automatic dilution is completed. Semiautomatic Start-Stop System - All auxiliary equipment used with this system is tied directly to the control circuit. It is necessary for the operating engineer to press the START button to start the condensing water pump, chilled water pump, machine pumps, and cooling tower fan (if used). PROCEDURES 1. Press STOP button to stop machine. START button to start machine. Press NOTE: On shutdown the machine pumps will continue to run until automatic dilution is completed. Semiautomatic Start-Stop System with Manual Auxiliaries - All auxiliaries must be started manually. PROCEDURES 1. Start chilled water pump. 2. Start condensing water pump. 3. Start cooling tower fan (if used). (This depends on outside temperature.) 4. Press START button to start machine. 5. To stop machine, press STOP button. Then stop the following: a. Cooling tower fan (if used). b. Condenser water pump. c. Chilled water pump. NOTE: The refrigerant and solution pumps will continue to run until automatic dilution is completed. MACHINE START-UP PROCEDURES General - Procedures for start-up differ depending on how long the machine has been shut down. There are two start-up procedures: Start-up after limited shutdown (3 days to 3 weeks), and start-up after extended shutdown (over 3 weeks). Start-Up After Limited Shutdown PROCEDURES 1. Start the machine as outlined for your system under Machine Start-Stop Systems. 2. Check the leaving chilled water temperature. If temperature drops to design, then steps 3 and 4 are not necessary. If the temperature does not drop to design, noncondensables are probably present in the machine. Proceed with steps 3 and 4. 3. Determine the amount of noncondensables by taking an absorber loss reading (the temperature difference between the refrigerant and solution vapor). To determine absorber loss, refer to Carrier Standard Service Techniques, publication SM-16. A machine with absorber loss of less than 6 F can normally be started without the machine solution becoming solidified. If absorber loss is greater than 6 F, auxiliary evacuation is recommended. A machine fully evacuated will normally have an absorber loss of 2 F or less. Instructions for auxiliary evacuation are in Carrier Standard Service Techniques, publication SM-16. © Carrier Corporation 1968 Printed in U.S.A. 1-68 16JA-1SO To prevent solidification while purging: a. Place reclaim switch to MANUAL. b. Throttle back steam control valve. (1) Electronic Control - Turn the control point adjustor up approximately ten degrees (ten divisions). (2) Pneumatic Control - Turn the chilled water thermostat set point up ten degrees. 4. Evaluate machine tightness with a noncon-densable accumulation rate check. Refer to Carrier Standard Service Techniques, publication SM-16. Start-Up After Extended Shutdown - This procedure is critical since accumulated noncon-densables may allow the machine solution to solidify if the following precautions are not taken. PROCEDURES 1. Start the machine as outlined for your system under Machine Start-Up Procedures. Make sure steam valve is closed. If absorber solution level is hig...