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

17to the vacuum indicator only when taking a reading.Leave the valve open for 3 minutes to allow the indicatorvacuum to equalize with the chiller vacuum.3. If the entire chiller is to be dehydrated, open all isolationvalves (if present).4. With the chiller ambient temperature at 60 F (15.6 C) orhigher, operate the vacuum pump until the manometerreads 29.8 in. Hg vac, ref 30 in. bar. (0.1 psia)(–100.61 kPa) or a vacuum indicator reads 35 F (1.7 C).Operate the pump an additional 2 hours.Do not apply a vacuum greater than 29.82 in. hg vac(757.4 mm hg) or allow the temperature to drop below33 F (0.5 C) on the wet bulb vacuum indicator. At thistemperature and pressure, isolated pockets of moisturecan turn into ice. The slow rate of evaporation (sublima-tion) of ice at these low temperatures and pressures great-ly increases dehydration time.Filling the heat exchanger tubes with warm water (100 F[38 C] or cooler) will warm any moisture clinging to thetubes and thus will increase the evaporation rate. If thewaterbox covers are open warm air can be blown throughthe tubes. Again observe the 100 F (38 C) limit.5. Valve off the vacuum pump, stop the pump, and recordthe instrument reading.6. After a 2-hour wait, take another instrument reading. Ifthe reading has not changed, dehydration is complete. Ifthe reading indicates vacuum loss, repeat Steps 4 and 5.7. If the reading continues to change after several attempts,perform a leak test up to the maximum 160 psig(1103 kPa) pressure. Locate and repair the leak, andrepeat dehydration.REMOVING REFRIGERANT — Machines with refriger-ant are usually provided with a storage tank and pumpout unitto permit refrigerant removal when performing service work.Refer to Pumpout System Operation section.WATER TREATMENT — In hard water areas, the condens-ing water system must be cleaned frequently (at least yearly) toprevent a rise in condenser pressure. Proper water treatmentand cooling tower bleedoff reduces the amount of scaling and,thereby, reduces frequency of tube cleaning required.Since water conditions vary in all parts of the country, it isrecommended that a reliable water treatment specialist be con-sulted and a sample of the condenser water tested to determinethe type of water treatment required.CLEARANCES — Clearances for compressor componentsshown in Fig. 4 and listed in Table 5 are a guide to be usedwhen checking or fitting a replacement part.GEAR AND DRIVE — Refer to gear and drive manufactur-er's instructions for maintenance requirements.PUMPOUT SYSTEM — Refer to Carrier Service Instruc-tions for 5F,H condensing units for maintenance.Table 5 — ClearancesTIR — Total Indicator ReadingGENERAL DATAMachine Nameplate — The machine nameplate withmachine serial number and machine designation is located onthe safety panel. These numbers include information about themachine. For example, 17DA81 indicates:17 - Open-drive centrifugal refrigeration compressorDA - Single-stage81 - Compressor sizeThe overall assembly as well as each major component hasa serial number. When corresponding with your Carrier repre-sentative, always give machine designation, machine serialnumber, and component serial numbers.Refrigerant Properties — Refrigerant is relativelysafe. The sweet-smelling vapor is nonflammable and nontoxic.Heavy concentrations may cause dizziness, headache, and lossof consciousness. When subjected to flame, refrigerant breaksdown into toxic gases. Avoid breathing fumes.Refrigerant dissolves oils and destroys natural rubber andall components containing rubber. Carefully selected neo-prenes are safe to use.Air or water floats on top of refrigerant in gas or liquid staterespectively. Being heavier than air, refrigerant will settle in alllow places. See Tables 6A and 6B for refrigerant temperaturevs pressure (saturated) relationships.Relief Valve Assembly — The relief valve assembly islocated on the refrigerant storage tank. It prevents dangeroushigh pressure from developing within the machine from fire orany other reason.System Components — The system components con-sist of the following:• Cooler - Heat exchanger which cools "brine" passingthrough the tubes by evaporation of the refrigerant in whichtubes are immersed.• Compressor - Machine which compresses the evaporatedrefrigerant and discharges it to the condenser.• Condenser - Heat exchanger which liquefies the evaporatedrefrigerant discharged into it from the compressor.• Purge Recovery Unit - A small condensing unit with separa-tor which continuously extracts gas from the top of the con-denser and purifies it by removing air which may bepresent.Fig. 7 — Dehydration Cold Trapa19-661DESCRIPTION ITEM(Fig. 4)DIMENSION(in.) MEASURETYPEMin MaxShaft End LabyrinthSeal EndThrust End18.008.001.011.003Dia.Dia.Journal BearingLabyrinthSeal and Thrust End 3 .005 .009 Dia.Impeller Eye — .026 .034 Dia.Balancing Piston 10 .032 .036 Dia.Journal Bearings 2, 5 .0035 .0055 Dia.Thrust Clearance — .008 .012 AxialThrust Disc FaceRunout 7 .0005 TIR AxialSeal Ring 9 .0015 .004 Dia.Seal Shoulder to SealHousing Face — 1 50/ 64 1 61 / 64 AxialShaft Movement(Safety) Switch Fig. 5 .014 .018 Fig. 5Seal Movement(Safety) Switch* 4 .020 .025 Axial