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YORK INTERNATIONAL

26

FORM 160.54-O2(1102)

FORM 160.54-O2(1102)

27

YORK INTERNATIONAL

VACUUM DEHYDRATION

To obtain a sufficiently dry system, the following in-

structions have been assembled to provide an effective 

method for evacuating and dehydrating a system in the 

field. Although there are several methods of dehy-

drating a system, we are recommending the following, 

as it produces one of the best results, and affords a 

means of obtaining accurate readings as to the extent of 

dehydration.

The equipment required to follow this method of de-

hydration consists of a wet bulb indicator or vacuum 

gauge, a chart showing the relation between dew 

point temperature and pressure in inches of mercury 

(vacuum), (See Table 2) and a vacuum pump capable 

of pumping a suitable vacuum on the system.

OPERATION

Dehydration of a refrigerant system can be obtained 

by this method because the water present in the 

system reacts much as a refrigerant would. By pull-

ing down the pressure in the system to a point where 

its saturation temperature is considerably below that 

of room temperature, heat will flow from the room 

through the walls of the system and vaporize the wa-

ter, allowing a large percentage of it to be removed by 

the vacuum pump. The length of time necessary for 

the dehydration of a system is dependent on the size 

or volume of the system, the capacity and efficiency 

of the vacuum pump, the room temperature and the 

quantity of water present in the system. By the use 

of the vacuum indicator as suggested, the test tube 

will be evacuated to the same pressure as the system, 

and the distilled water will be maintained at the same 

saturation temperature as any free water in the system, 

and this temperature can be observed on the thermom-

eter.

If the system has been pressure tested and found to be 

tight prior to evacuation, then the saturation tempera-

ture recordings should follow a curve similar to the 

typical saturation curve shown as Fig. 12.

The temperature of the water in the test tube will drop 

as the pressure decreases, until the boiling point is 

reached, at which point the temperature will level off 

and remain at this level until all of the water in the 

shell is vaporized. When this final vaporization has 

taken place the pressure and temperature will continue 

to drop until eventually a temperature of 35°F (1.6°C) 

or a pressure of 5 mm Hg. is reached.

When this point is reached, practically all of the air 

has been evacuated from the system, but there is still 

a small amount of moisture left. In order to provide 

a medium for carrying this residual moisture to the 

vacuum pump, nitrogen should be introduced into the 

system to bring it to atmospheric pressure and the indi-

cator temperature will return to approximately ambient 

temperature. Close off the system again, and start the 

second evacuation.

The relatively small amount of moisture left will be 

carried out through the vacuum pump and the tem-

perature or pressure shown by the indicator should 

drop uniformly until it reaches a temperature of 35°F 

(1.6°C) or a pressure of 5 mm Hg.

When the vacuum indicator registers this temperature 

or pressure, it is a positive sign that the system is 

evacuated and dehydrated to the recommended limit. 

If this level cannot be reached, it is evident that there 

is a leak somewhere in the system. Any leaks must be 

corrected before the indicator can be pulled down to 

35°F or 5 mm Hg. in the primary evacuation.

During the primary pulldown, keep a careful watch 

on the wet bulb indicator temperature, and do not let 

it fall below 35°F (1.6°C). If the temperature is al-

lowed to fall to 32°F (0°C), the water in the test tube 

will freeze, and the result will be a faulty temperature 

reading.

FIG. 12 – 

SATURATION CURVE

LD00474

6

Содержание MaxE YK Series

Страница 1: ...ETM CENTRIFUGAL LIQUID CHILLERS Supersedes NOTHING Form 160 54 O2 1102 MODEL YK STYLE E R 134a COOLING ONLY WITH OPTIVIEWTM CONTROL CENTER FOR ELECTRO MECHANICAL STARTER SOLID STATE STARTER VARIABLE SPEED DRIVE 00611VIP LDO5842 ...

Страница 2: ... materials This individual shall also be familiar with and comply with all applicable governmental standards and regulations pertaining to the task in question SAFETY SYMBOLS The following symbols are used in this document to alert the reader to areas of potential hazard WARNING indicates a potentially hazardous situation which if not avoided could result in death or se rious injury DANGER indicat...

Страница 3: ...CF CG 5CR 5OJ 5CS In complying with YORK s policy for continuous product improvement the information contained in this document is subject to change without notice While YORK makes no commitment to update or provide current information automatically to the manual owner that information if applicable can be obtained by contacting the nearest YORK Applied Systems Service office REFERENCE INSTRUCTION...

Страница 4: ... System and Fundamentals of Operation 7 SECTION 2 System Operating Procedures 9 SECTION 3 System Components Description 15 SECTION 4 Operational Maintenance 21 SECTION 5 Troubleshooting 23 SECTION 6 Maintenance 25 SECTION 7 Preventive Maintenance 34 TABLE OF CONTENTS ...

Страница 5: ... 10 FIG 4 CHILLER STARTING SEQUENCE SHUTDOWN SEQUENCE VARIABLE SPEED DRIVE 11 FIG 5 LIQUID CHILLER LOG SHEETS 12 FIG 6 SYSTEM COMPONENTS 15 FIG 7 SCHEMATIC DRAWING YK COMPRESSOR LUBRICATION SYSTEM 16 FIG 8 OIL RETURN SYSTEM 18 FIG 9 CHARGING OIL RESERVOIR WITH OIL 21 FIG 10 EVACUATION OF CHILLER 22 FIG 11 SYSTEM PRESSURES 25 FIG 12 SATURATION CURVE 27 FIG 13 DIAGRAM MEGGING MOTOR WINDINGS 29 FIG 1...

Страница 6: ... O Board and Motor Controller circuit Refer to SECTION 1 DESCRIPTION OF SYSTEM AND FUNDAMENTALS OF OPERATION 00116vip CONDENSER CONTROL CENTER COMPRESSOR MOTOR EVAPORATOR FIG 1 MODEL YK MAXETM CHILLER SYSTEM OPERATION DESCRIPTION SEE FIG 2 The YORK Model YK MaxETM Chiller is commonly applied to large air conditioning systems but may be used on other applications The chiller consists of an open mot...

Страница 7: ...eat from the refrigerant vapor causing it to condense The condenser water is supplied to the chiller from an ex ternal source usually a cooling tower The condensed refrigerant drains from the condenser into the liquid return line where the variable orifice meters the flow of liquid refrigerant to the evaporator to complete the refrigerant circuit The major components of a chiller are selected to h...

Страница 8: ...L 8 FORM 160 54 O2 1102 FIG 2 REFRIGERANT FLOW THRU CHILLER PREROTATION VANES See Detail A SUCTION EVAPORATOR ELIMINATOR OIL COOLER LD00924 FLOW CONTROL ORIFICE SUB COOLER CONDENSER DISCHARGE BAFFLE DISCHARGE COMPRESSOR ...

Страница 9: ...fter start up the excess oil may be drained from the oil filter drain valve while the compressor is running If oil level is low oil should be added to the com pressor See Oil Charging Procedure page 22 Comply with EPA and Local regu lations when removing or dispos ing of Refrigeration System oil START UP PROCEDURE Pre Starting Prior to starting the chiller observe the OptiView Control Center Make ...

Страница 10: ...mp will start to circulate oil for a 50 second pre run to establish oil flow and adequate lubrication to all bearings gears and rotating sur faces within the compressor The high and low oil pressure transducers OP and the oil temperature sensor RT3 will sense any malfunction in the lubrication system 3 The anti recycle timer software function will op erate after the 50 seconds of pre run time At t...

Страница 11: ...rent limit software function plus the 3 phase 100 solid state overload current limiter CM 2 on Electro Mechanical Starter applications or the Solid State Starter current Limit function will override the temperature control func tion and prevent the Prerotation Vanes from opening beyond the CURRENT LIMIT setting NOT FOR ALL SHUTDOWNS REFER TO DISPLAY MES SAGES SECTION OF THIS MANUAL System Operatin...

Страница 12: ... entering condenser water tempera ture may be as much as 25 F 14 C colder than the standby return chilled water temperature Cooling tower fan cycling will normally provide adequate control of the entering condenser water temperature on most installations OPERATING LOG SHEET A permanent daily record of system operating condi tions temperatures and pressures recorded at regular intervals throughout ...

Страница 13: ...s necessary 5 Perform refrigerant analysis NEED FOR MAINTENANCE OR SERVICE If the system is malfunctioning in any manner or the unit is stopped by one of the safety controls consult the Operation Analysis Chart Table 1 pages 23 and 24 of this instruction After consulting this chart if you are unable to make the proper repairs or adjust ments to start the compressor or the particular trouble contin...

Страница 14: ... carefully drain the cooling water from the cooling tower condenser condenser pump and the chilled water system chilled water pump and coils Open the drains on the evaporator and condenser liquid heads to assure complete drainage If a Variable Speed Drive drain its water cooling sys tem If Solid State Starter drain water from starter cooling loop 3 On the SETUP Screen disable the clock This conser...

Страница 15: ...L SECTION 3 SYSTEM COMPONENTS DESCRIPTION MOTOR EVAPORATOR COMPRESSOR SUCTION DUAL RELIEF VALVES SIGHT GLASS VARIABLE SPEED OIL PUMP CONTROL BOX REFRIGERANT CHARGING VALVE 00611vip FRONT VIEW FIG 6 SYSTEM COMPONENTS OPTIVIEW CONTROL CENTER 3 ...

Страница 16: ...YORK INTERNATIONAL 16 FORM 160 54 O2 1102 FIG 7 SYSTEM COMPONENTS CONT D 28778A DISCHARGE LINE OIL COOLER OIL RESERVOIR PUMP REAR VIEW System Components Description ...

Страница 17: ... all interconnecting oil piping and passages There are main points within the motor com pressor which must be supplied with forced lubrication as follows 1 Compressor Drive Shaft Low Speed a Shaft seal b Front and rear journal bearings one on each side of driving gear c Low speed thrust bearing forward and reverse 2 Compressor Driven Shaft High Speed a Forward and reverse high speed thrust bearing...

Страница 18: ...YORK INTERNATIONAL 18 FORM 160 54 O2 1102 LOW SPEED GEAR REAR BEARING DOUBLE BELLOWS SHAFT SEAL FIG 8 SCHEMATIC DRAWING YK COMPRESSOR LUBRICATION SYSTEM LD08577 System Components Description ...

Страница 19: ...rcurrent transformers are furnished with all units HEAT EXCHANGERS Evaporator and condenser shells are fabricated from rolled carbon steel plates with fusion welded seams Heat exchanger tubes are internally enhanced type The evaporator is a shell and tube flooded type heat exchanger A distributor trough provides uniform distribution of refrigerant over the entire shell length Stainless steel mesh ...

Страница 20: ... refrigerant Isolation of the refrigerant in this system must be performed by a quali fied service technician OPTIONAL HOT GAS BYPASS Hot gas bypass is optional and is used to eliminate compressor surge during light load or high head operation The OptiView control panel will automati cally modulate the hot gas valve open and closed as required Adjustment of the hot gas control valve must be perfor...

Страница 21: ...nducing the low pressure oil rich liquid to flow from the evaporator through the dehy drator to the compressor sump CHANGING THE DEHYDRATOR To change the dehydrator use the following pro cedure 1 Shut the stop valves on the condenser gas line oil return line to rotor support and inlet end of the dehydrator 2 Remove the dehydrator Refer to Fig 9 3 Assemble the new filter drier 4 Open condenser stop...

Страница 22: ...il charging valve A located on the remote oil reservoir cover plate See Fig 9 Do not tighten the connection at the charging valve until after the air is forced out by pumping a few strokes of the oil pump This fills the lines with oil and prevents air from being pumped into the system 3 Open the oil charging valve and pump oil into the system until oil level in the compressor oil res ervoir is abo...

Страница 23: ...gerant refrigerant into system greater than normal with high discharge Variable orifice problem Remove obstruction temperature Temperature difference between leaving Evaporator tubes dirty or Clean evaporator tubes chilled water and refrigerant in the evaporator restricted greater than normal with normal discharge temperature Temperature of chilled water too low with Insufficient load for Check pr...

Страница 24: ...YMPTOM REDUCED OIL PUMP CAPACITY Oil pump pumping capacity Excessive end clearance Inspect and replace worn parts pump Other worn pump parts Partially blocked oil supply Check oil inlet for blockage inlet 8 SYMPTOM OIL PRESSURE GRADUALLY DECREASES Noted by Observation of Daily Log Sheets When oil pump VSD frequency increases Oil filter is dirty Change oil filter to 55 hz to maintain target oil pre...

Страница 25: ...ector can be used to detect any leaks too small to be found by the soap test To test with R 22 proceed as follows 1 With no pressure in the system charge R 22 gas into the system through the charging valve to a pressure of 2 PSIG 14 kPa 2 Build up the system pressure with dry nitrogen to approximately 75 to 100 PSIG 517 to 690 kPa To be sure that the concentration of refrigerant has reached all pa...

Страница 26: ... disconnect the vacuum pump leaving the vacuum indicator in place 6 Hold the vacuum obtained in Step 3 in the system for 8 hours the slightest rise in pressure indicates a leak or the presence of moisture or both If after 24 hours the wet bulb temperature in the vacuum indi cator has not risen above 40 F 4 4 C or a pressure of 6 3 mm Hg the system may be considered tight Be sure the vacuum indicat...

Страница 27: ... and found to be tight prior to evacuation then the saturation tempera ture recordings should follow a curve similar to the typical saturation curve shown as Fig 12 The temperature of the water in the test tube will drop as the pressure decreases until the boiling point is reached at which point the temperature will level off and remain at this level until all of the water in the shell is vaporize...

Страница 28: ...0 lbs 207 345 862 or 12 066 kg of refrigerant TABLE 3 REFRIGERANT CHARGE CHECKINGTHEREFRIGERANTCHARGE DURINGUNITSHUTDOWN The refrigerant charge is specified for each chiller model See Table 3 Charge the correct amount of refrigerant and record the level in the evaporator sight glass The refrigerant charge should always be checked and trimmed when the system is shut down The refrigerant charge leve...

Страница 29: ... the condenser or evaporator compressor while making any necessary repairs While the main disconnect switch and compressor motor starter are open meg the motor as follows 1 Using a megohm meter megger meg between phases and each phase to ground See Fig 13 these readings are to be interpreted using the graph shown in Fig 14 2 If readings fall below shaded area remove ex ternal leads from motor and ...

Страница 30: ...TERNATIONAL 30 FORM 160 54 O2 1102 LD00476 FIG 14 MOTOR STARTER TEMPERATURE AND INSULATION RESISTANCES Minimum Insulation Resistance vs Temperature per IEEE Std 43 Open Motors Maintenance TEMPERATURE F MEGOHMS ...

Страница 31: ...d pressure over a period of time accompanied by a steady rise in condensing temperature and noisy operation These symptoms may also be due to foul gas buildup Purging will remove the foul gas revealing the effect of fouling TUBE FOULING Fouling of the tubes can be due to deposits of two types as follows 1 Rust or sludge which finds its way into the tubes and accumulates there This material usually...

Страница 32: ...d the ends of all tubes with water Do not use carbon tetrachloride for this purpose since its fumes give the same flame discoloration that the refrigerant does 3 With nitrogen or dry air blow out the tubes to clear them of traces of refrigerant laden moisture from the circulation water As soon as the tubes are clear a cork should be driven into each end of the tube Pressurize the dry system with 5...

Страница 33: ...s passages or dirty oil filters If the unit is shutting down on HOT High Oil Temperature or Low Oil Pressure OP change the oil filter element Examine the oil filter element for the presence of aluminum particles Aluminum gas seal rings can contact the impeller and account for some aluminum particles to accumulate in the oil filter espe cially during the initial start up and first several months of...

Страница 34: ...s are not supplied and bearings are designed for long life under standard conditions Frames 284T thru 587UZ are furnished with double shielded or open ball or roller bearings It is neces sary to re lubricate anti friction bearings periodically See Table 4 Frame Size Standard 8hr Day Continuous 24hr Day Grease Qty oz 143T 256T 7 Years 3 Years 1 284TS 286TS 210 Days 70 Days 1 324TS 587USS 150 Days 5...

Страница 35: ... user to provide for proper water treatment to provide for a longer and more economical life of the equipment The following recommendation should be followed in determining the condition of the water side of the condenser and evaporator tubes 1 The condenser tubes should be cleaned annually or earlier if conditions warrant If the temperature difference between the water off the condenser and the c...

Страница 36: ...800 861 1001 www york com P O Box 1592 York Pennsylvania USA 17405 1592 Subject to change without notice Printed in USA Copyright by York International Corporation 2002 ALL RIGHTS RESERVED Form 160 54 O2 1102 Supersedes NOTHING ...

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