Carrier 17DA Start-up, Operation And Maintenance Instructions Manual

Also see for 17DA: Start-up instructions Application data Operating and maintenance instructions Start-up instructions

15machine refrigerant pressure, so that any oil leakage throughthe seal is always in an inward direction.CHECK STARTERS AND VFDS — Refer to the starter/VFD manufacturer’s instructions for specific procedures.General items that must be addressed (where applicable):• Tightness of all power cable and other wire connections• Inspect all connections for evidence of excessive tempera-ture and investigate cause when evidence is found, cleanand remake the connection:• Operation of cooling fans• Dirt, corrosion, carbon tracking and oily contamination ofmechanisms and contacts• Soot, stained areas, evidence of smoke must be investigatebefore cleaning• Megohm testing of power cables• Lubrication and free operation of contactor mechanisms• Contact condition, alignment and remaining overtravel.Manufacturer’s literature will provide the minimum over-travel• Circuit breaker calibration• Operation of all safeties and interlocks• Calibration of safeties• Isolation switch operationCOMPRESSOR BEARING MAINTENANCE — The keyto good bearing maintenance is proper lubrication. Use theproper grade of oil, maintained at recommended level, tem-perature, and pressure. Inspect the lubrication system regu-larly and thoroughly.CHANGE OIL AND OIL FILTER — Periodic oil samplesshould be used as guidance regarding the necessity of oilchanges. Contaminants and evidence of deterioration by thepresence of acid are of primary importance. Synthetic oil doesnot break down and lose viscosity over time under normaloperation.The oil filters should be changed at a minimum of one yearintervals. The oil charge is 35 gallons. Carrier supplies suitableoil under part number PP23BZ106.To remove oil charge from oil reservoir, proceed as follows:1. Find two 1/2-in. plugs in the side of the reservoir locatedbeneath the pump motor end. Use bottom plug.2. Remove plug. Drain oil into suitable container and re-place plug.INSPECT COOLER TUBES — Inspect tubes and clean atthe end of the first operating season. Condition indicates fre-quency of cleaning required in future and also whether or notwater treatment is required in chilled water circuit.A yearly eddy current test of the heat exchanger tubes willreveal most damage and enable corrective action to prevent aneventual failure.INSPECT CONDENSER TUBES — Inspect tubes and cleanyearly or more often if water is contaminated. Higher than nor-mal condenser pressure usually indicates dirty tubes. Air in ma-chine also results in high pressures.Open systems and make-up water result in condenser tubesfouled by scale and algae. A specialist should analyze waterand recommend treatment required.Brushes designed to prevent scraping of tube walls are soldthrough Carrier Service Center. Hard scale may require chemi-cal cleaning.INSPECT PURGE RECOVERY UNIT — Close purge ser-vice valves. This unit handles corrosive mixtures at their high-est concentration and protects machine. Keep it in good operat-ing condition. See Fig. 6 for purge evacuator assembly compo-nents. Proceed as follows:1. Remove purge cover from purge evacuator assembly.2. Remove evacuator valve and float assembly.3. Clean refrigerant float chamber.4. Operate float valve through full travel. Valve must movefreely without binding.5. Examine valve plunger and seat for dirt and wear. Re-place plunger and seal assembly if worn.6. Reinstall components using new sealing gaskets.7. Check 1/16-in. orifice in strainer/orifice assembly (Item6, Fig. 6). Clean strainer (Item 7, Fig. 6).8. Replace the strainer.General MaintenanceREFRIGERANT LEVEL — Excessive refrigerant in coolercauses liquid droplets to be pulled into compressor suction andrequires excess power for tonnage produced.Too little refrigerant reduces the number of tubes that coolthe water, causing inlet guide vanes to open, thus further reduc-ing cooler pressure. The machine may shut down on refrigerantlow-pressure cutout even though chilled water temperature istoo high.Proper refrigerant charge is indicated when difference be-tween leaving chilled water temperature and cooler tempera-ture reaches design conditions, or becomes a minimum at de-sign load conditions. To determine the approximate refrigerantcharge for your machine, add the cooler charge to the applica-ble condenser charge as listed in Table 3.The optimum operating charge for the machine must be de-termined by adjusting the charge during operation at or nearfull design load. See Charge Refrigerant in the Start-up sectionof this manual. The optimum charge level should be marked onthe cooler level sight glass. This allows the correct amount ofrefrigerant to be returned to the machine after service or a sea-sonal shutdown.Refrigerant loss is always due to leaks, since the 17DA ma-chine operates at pressures above atmospheric. Check over themachine frequently with approved refrigerant leak-detectingequipment. Repair all leaks.LEAK TESTING — Since HFC-134a is above atmosphericpressure at normal operating temperatures, effective leak test-ing can be done with refrigerant in the machine. Refrigerantmay have to be pumped out to storage tank before leaks arerepaired.If the machine is empty of refrigerant, proceed as follows:1. Use HFC-134a as a tracer gas. Pressurize the machinewith HFC-134a vapor to 20 psig (138 kPa).2. Complete the pressurization using a dry gas (nitrogen) to90 to 100 psig (620 to 690 kPa). Maximum test pressureis 150 psig (1034 kPa). Never use air to pressurize ma-chine for a leak test. A serious explosion may result.3. Leak test using an electronic leak detector suitable forHFC-134a. Test all joints and flanges, including thepumpout and purge units. Repair all leaks and repeat testsuntil machine is tight. A heavy concentration of refriger-ant in the machine room decreases leak testing efficiency.Ventilate the room well with ample fresh air before at-tempting final leak test operation.CHECK LEAKAGE RATE — Proceed as follows:1. Start the chilled water and condensing water pumps.2. Use external vacuum pump to pull 25 in. (635 mm) mer-cury vacuum on machine.3. Valve machine off. Turn vacuum pump off. Stop waterpumps. Leave oil pump running.4. A vacuum loss rate of 0.05 in. (1 mm) mercury per 24hours or less indicates acceptable leak tightness.