Carrier 17DA Specifications

17DA
Open-Drive Centrifugal Liquid Chillers
50/60 Hz
HFC-134a
Start-Up, Operation, and Maintenance Instructions
SAFETY CONSIDERATIONS
Centrifugal liquid chillers are designed to provide safe and
reliable service when operated within design specifications. When operating this equipment, use good judgment
and safety precautions to avoid damage to equipment and
property or injury to personnel.
Be sure you understand and follow the procedures and
safety precautions contained in the chiller instructions as
well as those listed in this guide.
DANGER
DO NOT VENT refrigerant relief valves within a building. Outlet
from rupture disc or relief valve must be vented outdoors in accordance with the latest edition of ANSI/ASHRAE 15 (American
National Standards Institute/American Society of Heating, Refrigeration, and Air Conditioning Engineers). The accumulation of refrigerant in an enclosed space can displace oxygen and cause asphyxiation.
PROVIDE adequate ventilation in accordance with ANSI/ASHRAE
15, especially for enclosed and low overhead spaces. Inhalation of
high concentrations of vapor is harmful and may cause heart irregularities, unconsciousness, or death. Misuse can be fatal. Vapor is heavier
than air and reduces the amount of oxygen available for breathing.
Product causes eye and skin irritation. Decomposition products are
hazardous.
DO NOT USE OXYGEN to purge lines or to pressurize a chiller for
any purpose. Oxygen gas reacts violently with oil, grease, and other
common substances.
NEVER EXCEED specified test pressures, VERIFY the allowable
test pressure by checking the instruction literature and the design pressures on the equipment nameplate.
DO NOT USE air for leak testing. Use only refrigerant or dry
nitrogen.
DO NOT VALVE OFF any safety device.
BE SURE that all pressure relief devices are properly installed and
functioning before operating any chiller.
RISK OF INJURY OR DEATH by electrocution. High voltage is
present on motor leads even though the motor is not running when a
solid-state or inside-delta mechanical starter is used. Open the power
supply disconnect before touching motor leads or terminals.
WARNING
DO NOT WELD OR FLAMECUT any refrigerant line or vessel until
all refrigerant (liquid and vapor) has been removed from chiller.
Traces of vapor should be displaced with dry air or nitrogen and the
work area should be well ventilated. Refrigerant in contact with an
open flame produces toxic gases.
DO NOT USE eyebolts or eyebolt holes to rig chiller sections or the
entire assembly.
DO NOT work on high-voltage equipment unless you are a qualified
electrician.
DO NOT WORK ON electrical components, including control panels, switches, starters, or oil heater until you are sure ALL POWER IS
OFF and no residual voltage can leak from capacitors or solid-state
components.
LOCK OPEN AND TAG electrical circuits during servicing. IF
WORK IS INTERRUPTED, confirm that all circuits are deenergized
before resuming work.
AVOID SPILLING liquid refrigerant on skin or getting it into the
eyes. USE SAFETY GOGGLES. Wash any spills from the skin with
soap and water. If liquid refrigerant enters the eyes, IMMEDIATELY
FLUSH EYES with water and consult a physician.
NEVER APPLY an open flame or live steam to a refrigerant cylinder.
Dangerous over pressure can result. When it is necessary to heat
refrigerant, use only warm (110 F [43 C]) water.
DO NOT REUSE disposable (nonreturnable) cylinders or attempt to
refill them. It is DANGEROUS AND ILLEGAL. When cylinder is
emptied, evacuate remaining gas pressure, loosen the collar and
unscrew and discard the valve stem. DO NOT INCINERATE.
CHECK THE REFRIGERANT TYPE before adding refrigerant to
the chiller. The introduction of the wrong refrigerant can cause damage or malfunction to this chiller.
Operation of this equipment with refrigerants other than those
cited herein should comply with ANSI/ASHRAE 15 (latest edition).
Contact Carrier for further information on use of this chiller with other
refrigerants.
DO NOT ATTEMPT TO REMOVE fittings, covers, etc., while
chiller is under pressure or while chiller is running. Be sure pressure is
at 0 psig (0 kPa) before breaking any refrigerant connection.
CAREFULLY INSPECT all relief devices, rupture discs, and other
relief devices AT LEAST ONCE A YEAR. If chiller operates in a
corrosive atmosphere, inspect the devices at more frequent intervals.
DO NOT ATTEMPT TO REPAIR OR RECONDITION any relief
device when corrosion or build-up of foreign material (rust, dirt, scale,
etc.) is found within the valve body or mechanism. Replace the
device.
DO NOT install relief devices in series or backwards.
USE CARE when working near or in line with a compressed spring.
Sudden release of the spring can cause it and objects in its path to act
as projectiles.
CAUTION
DO NOT STEP on refrigerant lines. Broken lines can whip about and
release refrigerant, causing personal injury.
DO NOT climb over a chiller. Use platform, catwalk, or staging. Follow safe practices when using ladders.
USE MECHANICAL EQUIPMENT (crane, hoist, etc.) to lift or
move inspection covers or other heavy components. Even if components are light, use mechanical equipment when there is a risk of slipping or losing your balance.
BE AWARE that certain automatic start arrangements CAN
ENGAGE THE STARTER, TOWER FAN, OR PUMPS. Open the
disconnect ahead of the starter, tower fans, or pumps.
USE only repair or replacement parts that meet the code requirements
of the original equipment.
DO NOT VENT OR DRAIN waterboxes containing industrial brines,
liquid, gases, or semisolids without the permission of your process
control group.
DO NOT LOOSEN waterbox cover bolts until the waterbox has been
completely drained.
DOUBLE-CHECK that coupling nut wrenches, dial indicators, or
other items have been removed before rotating any shafts.
DO NOT LOOSEN a packing gland nut before checking that the nut
has a positive thread engagement.
PERIODICALLY INSPECT all valves, fittings, and piping for corrosion, rust, leaks, or damage.
PROVIDE A DRAIN connection in the vent line near each pressure
relief device to prevent a build-up of condensate or rain water.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53170002-01
Printed in U.S.A.
Form 17DA-3SS
Pg 1
3-09
Replaces: 17DA-2SS,
17DA-3SO
Page
• CHECK PURGE FREQUENCY
• WATER IN PURGE WATER CHAMBER
Yearly Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
• CHECK/CALIBRATE WATER TEMPERATURE
SENSORS
• CHECK REFRIGERANT LOW-PRESSURE CUTOUT
• CHECK CONDENSER HIGH-PRESSURE CUTOUT
• CHECK AUXILIARY OIL PUMP CONTROL
• CHECK SEAL OIL DIFFERENTIAL PRESSURE
TRANSDUCER
• CHECK THRUST BEARING OIL PRESSURE
TRANSDUCER
• CHECK DISCHARGE GAS HIGH-TEMPERATURE
CUTOUT
• CHECK THRUST BEARING OIL HIGH-TEMPERATURE CUTOUT
• CHECK SHAFT MOVEMENT SWITCH
• CHECK COOLER AND CONDENSER MINIMUM
FLOW PROTECTION
• CHECK AUXILIARY INTERLOCKS
• CHECK CONDENSER SUBCOOLER LEVEL
CONTROL
• CHECK COMPRESSOR GUIDE VANE CONTROL
• CHECK STARTERS AND VFDS
• CHECK PRESSURE REGULATORS
• COMPRESSOR BEARING AND GEAR
MAINTENANCE
• CHANGE OIL AND OIL FILTER
• INSPECT COOLER TUBES
• INSPECT CONDENSER TUBES
• INSPECT PURGE RECOVERY UNIT
General Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
• REFRIGERANT LEVEL
• LEAK TESTING
• CHECK LEAKAGE RATE
• BREAKING VACUUM
• PREPARING MACHINE FOR CHARGING
REFRIGERANT
• CHILLER DEHYDRATION
• REMOVING REFRIGERANT
• WATER TREATMENT
• CLEARANCES
• GEAR AND DRIVE
• PUMPOUT SYSTEM
GENERAL DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-20
Machine Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Refrigerant Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Relief Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Refrigeration Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Oil Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Purge Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . 20-22
Compressor Will Not Start. . . . . . . . . . . . . . . . . . . . . . . 20
Compressor Surge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Chilled Water Temperature Too High . . . . . . . . . . . . 20
Chilled Water Temperature Too Low with
Compressor Running. . . . . . . . . . . . . . . . . . . . . . . . . . 22
Refrigerant Temperature Too Low . . . . . . . . . . . . . . . 22
Leaving Chilled Water Temperature Fluctuates . . 22
Condenser Pressure Too High. . . . . . . . . . . . . . . . . . . 22
Oil Pressure Too Low. . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Oil Pressure Too High . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Oil Reservoir Temperature Too Low . . . . . . . . . . . . . 22
Oil Reservoir Temperature Too High. . . . . . . . . . . . . 22
Compressor Discharge Gas Temperature
Too High. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
CONTROLS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-27
Safety Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Operating Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
PRE-START UP CHECK LIST . . . . . . . . . . . . . . . . . CL-1
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . 1
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Factory Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Job Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Field-Supplied Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Inspect Machine Room . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Drive Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
• AUXILIARY EQUIPMENT WIRING
• TURBINE DRIVE WIRING
• GAS ENGINE DRIVE WIRING
Safety Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Motor Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Gas Engine Drive. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Turbine Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pumpout System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Leak Test and Dehydration . . . . . . . . . . . . . . . . . . . . . . . 4
Charge Machine with Water . . . . . . . . . . . . . . . . . . . . . . 5
Charge Machine with Oil . . . . . . . . . . . . . . . . . . . . . . . . . 5
Final Pre-Operation Alignment Check . . . . . . . . . . . . 5
Operate Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Set Purge Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Check Water Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Check Air Supply (Pneumatic Machines) . . . . . . . . . 6
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Pre-Operation Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Drive Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Initial Refrigerant Charge. . . . . . . . . . . . . . . . . . . . . . . . . 6
Initial Compressor Operation . . . . . . . . . . . . . . . . . . . . . 6
Adjust Refrigerant Charge. . . . . . . . . . . . . . . . . . . . . . . . 6
Hot Alignment Check and Doweling . . . . . . . . . . . . . . 7
Operational Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Instruct Customer Operator . . . . . . . . . . . . . . . . . . . . . . 7
• CONTROL PANEL
• VFD
• STEAM TURBINE
• GAS ENGINE
• OPERATING PROCEDURES
• LOG SHEETS
Operator Duties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Start Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-13
Manual Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Cold Weather Operation . . . . . . . . . . . . . . . . . . . . . . . . . 10
Stop Machine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Extended Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Pumpout System Operation . . . . . . . . . . . . . . . . . . . . . 11
• LUBRICATION
• CONTROL DESCRIPTION
• CONTROL SETTING
• MACHINE AND STORAGE TANK EVACUATION
(No Refrigerant in System)
• REMOVE AIR AFTER OPENING CHILLER TO
ATMOSPHERE (Refrigerant Charge in Storage Tank)
• TRANSFER REFRIGERANT CHARGE (From Storage
Tank to Machine)
• TRANSFER REFRIGERANT CHARGE (From
Machine to Storage Tank Located Below Machine)
• TRANSFER REFRIGERANT CHARGE (From
Machine to Storage Tank Located Above or Level with
Machine)
• PRESSURIZE MACHINE AND STORAGE TANK (No
Refrigerant in System)
• DISTILL REFRIGERANT CHARGE
• CHARGE REFRIGERANT
MAINTENANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-17
Weekly Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
• CHECK OIL LEVEL
2
Piping — Check the following piping installation locations:
INTRODUCTION
1.
2.
3.
4.
1. 17DA Start-Up, Operation and Maintenance Instructions
2. Job drawings showing:
a. Machine assembly
b. Machine wiring
c. Machine piping
d. Controls and related wiring
3. Manufacturer's Installation and Start-Up Instructions for:
a. Drive
b. Gear (if applicable)
Refrigerant pumpout system
External or auxiliary oil system
All bypass lines and valves
Turbine drive piping
a. Blowdown valves for each turbine stage installed
per manufacturer's instructions.
b. Trace all field installed piping to the turbine to
ensure that it conforms to the turbine manufacturers installation instructions.
c. Steam supply line condensate traps must be properly installed to keep condensate out of the turbine.
A condensate drain should be located immediately
ahead of the trip and throttle valve so that all condensate may be cleared from the steam line immediately before steam is admitted to the turbine.
d. Proper supports on steam supply and exhaust line
to prevent stress or strain on the turbine at operating temperatures.
e. Coupling alignment should be checked before and
after the steam pipe is heated and before the turbine warm-up has begun. A change in alignment
indicates a possible pipe strain that must be
corrected.
5. Gas engine drive piping (check the following piping
for agreement with job blueprints):
a. Gas pressure reducing valves with shutoff valves.
b. Engine coolant piping with coolant thermostatic
valve installed so that water flows in direction
marked on valve.
c. Oil cooler package piping
d. Exhaust piping
NOTE: Exhaust piping is critical. Refer to drive manufacturer's recommendations for installation of exhaust piping.
Field-Supplied Tools — The following field-supplied
Wiring — Refer to job wiring diagrams. All wiring must
General — All persons concerned with the start-up and operation of the centrifugal refrigeration machine should be familiar with the equipment involved. This instruction book is intended to cover general rules for start-up procedures, followed
by operation and maintenance instructions.
Because of machine variations it is not possible to prepare
an instruction book covering all minor details. This instruction
book will fulfill common requirements. Additional information
pertaining to this particular chiller is included in the special job
binder provided with the chiller upon delivery. This includes
the prime mover, custom controls, instruments, etc.
Special attention should be given to precautionary instructions emphasized in this book to avoid start-up difficulties.
These precautions are, in general, applicable to all sizes of
17DA centrifugal refrigeration machines.
Instructions for the prime mover if not included with Carrier
Air Conditioning instructions should be obtained from the
manufacturer.
Factory Test — Prior to shipment, the compressor is completely assembled and tested. Performance as to lubrication,
speed balance and general mechanical operation has been determined to be satisfactory.
Job Data — The job consists of the following:
agree with these drawings.
AUXILIARY EQUIPMENT WIRING —
Check the
following:
1. Brine pump
2. Condenser water pump
3. Cooling tower fan motor
4. Auxiliary oil pump
5. Oil heater
6. Overload selections in all motor starters. Overload values
must agree with motor nameplate data.
TURBINE DRIVE WIRING — Check the following:
1. Turbine solenoid trip mechanism.
2. Auxiliary oil pump if used. Check pump starter for proper
voltage, amperage, and overload setting. Operate pump to
determine direction of rotation. Do not operate dry of oil.
3. Check job drawings for other electrical devices used with
the turbine. Ensure that their wiring agrees with the job
wiring blueprints.
GAS ENGINE DRIVE WIRING — All wiring must agree
with job wiring diagrams. Refer to engine manufacturer's instructions for starting techniques.
tools are need for installation and start up of the 17DA chiller:
• General mechanics tools
• Alignment tools consisting of a laser alignment instrument
or dial indicators and brackets and a low profile hydraulic
cylinder jack with hydraulic pump. These are used to
accomplish initial alignment and “hot check.”
• Digital volt-ohmmeter. This is used for instrument calibration. (Test voltage from analog ohmmeters can destroy RTD
[resistance temperature detector] sensors.)
• 4-20 mA signal generator. This is used for instrument calibration including valve positioners.
• Portable vacuum pump capable of reaching dehydration
vacuum with a capacity of 5 cfm or greater used for chiller
evacuation and dehydration.
• Electronic or wet-bulb vacuum indicator for measurement
of vacuum level.
• Electronic leak detector suitable for non-chlorinated
refrigerants.
Inspect Machine Room — All installation work as
outlined in 17DA Installation Instructions book should be completed, and all construction debris must be removed from the
immediate area of the machinery prior to initial start-up of the
machine.
Drive Arrangement — Inspect drive mounting, loca-
Safety Controls — Safety controls can be a combination
of electronic sensors supplying information to the programmable logic controller (PLC), mechanical switches which supply
an open/closed signal to the PLC, and mechanical devices that
act directly on the equipment with follow-up action provided
by the PLC. The PLC is shown in Fig. 1. A turbine overspeed
tion, coupling, speed rating, etc., for agreement with job drawings and specifications. Gear assembly (if used) must agree
with installation recommendations outlined in gear manufacturer's instructions.
3
trip is a good example of the type of safety that acts directly. If
specified, there may be both sensor inputs and mechanical
switches monitoring some points.
Refer to Table 1 for set points, except for the settings supplied
with the machine documentation. Job documentation will take
precedence over these standard settings.
Temperature switches should be set in a temperature bath and
compared to an accurate standard or electronic thermometer.
Pressure switches should be set using an accurate gage and a
controlled pressure source.
Pressure transducers should be checked using an accurate
gage and a controlled pressure source.
Thermistor and RTD sensor panel readouts should be compared to the temperature to which they are exposed. If possible,
hold the sensor in ambient air and compare the reading with an
accurate thermometer.
Mechanical interlock and limit switch operation must be confirmed by testing the actuator.
The turbine overspeed linkage should be tested before the turbine is powered. The trip actuator in the shaft can only be tested
by running the turbine. Once the turbine can run, it should be
gradually brought up to trip speed. If the turbine fails to trip at
the trip speed, then it should be shut down immediately and not
be started until a turbine manufacturer’s representative corrects
the problem.
Gas Engine Drive — Engine drives will be tested and
started by the engine manufacturer's representative. Control interfaces will be tested by the Carrier technician in co-operation
with the engine manufacturer's representative. A check list from
the engine manufacturer must be completed before the engine
service representative is called.
Turbine Drive — Turbines have their own safety systems
which should be tested according to the instructions found in
their manufacturer’s literature. If the manufacturer’s instructions
are not available, they must be obtained from the local Carrier
representative or from the turbine manufacturer.
Interlocks between the chiller controls and the turbine controls must be tested. The chiller must energize a solenoid which
then allows the trip and throttle valve to be set. If the solenoid is
deenergized, then the turbine trip and throttle valve must immediately close.
A feedback switch to the chiller controls is located on the trip
and throttle valve. The switch must close when the valve is
opened. This provides a RUN signal to the chiller controls which
will then start to load the compressor. If the trip and throttle
valve is closed by a trip from either the chiller or turbine controls, then this switch will open. This is a signal to the chiller that
the turbine has tripped and the chiller will enter a safety shutdown mode.
Other interlocks, signals and feedbacks will vary with the job.
Consult the job controls manual and the field control drawings
for the entire chiller and for the turbine.
All items on Pre-Start-Up Checklist must be completed before the turbine service representative is called.
Motor Drive — Accurate communication between the controls and the starter/VFD (variable frequency drive) must be confirmed by test. For equipment of the size and capacity of the
17DA chiller, it is likely that the control panel and the starter/
VFD will communicate through a data line, not through hardwired circuits. There may be an “Emergency Stop” button hardwired between the control panel and the starter.
Where the chiller controls and ancillary equipment controls
are connected to a building automation system via data lines, it
must be confirmed that the central system cannot override the
chiller safeties nor energize any chiller component directly. The
starter or VFD, in particular, must be protected from being energized by a command from anywhere other than the chiller controls. With the starter in a safety mode or disconnected from the
motor, attempts to energize the starter should be made from the
building controls to confirm that the building control system cannot energize the starter directly.
If the starter can be energized, reprogramming of the control
system is essential before the starter is put on-line. Accidental
starting of the motor could have extreme consequences to the
chiller.
The program correction should be made in the starter/VFD
control system rather than in the building control system so that
future updates to the building controls do not remove this
protection.
Pumpout System — The low-pressure cutout should be
set at the saturated pressure of refrigerant R-134a at 34 F (1 C).
A manual bypass switch is required to allow complete evacuation of the cooler. See Table 2.
Leak Test and Dehydration — Check the absolute
pressure on the refrigerant side of the machine. The final operation of the 17DA installation is to leak test the machine and dehydrate it to the point where it maintains a pressure of 0.21 psia
(1 kPa) (equivalent to 29.48 in. [749 mm] mercury vacuum referenced to a 30 in. [762 mm] barometer). Refer to the Leak Testing and Chiller Dehydration sections on pages 15 and 16.
If the machine absolute pressure is higher than the above values, repeat the evacuation and dehydration pumpdown operations until the machine proves to have a leak rate or vacuum loss
at a rate less than 0.1 in. (2 mm) mercury column in 24 hours.
The oil will always contain a minimal amount of dissolved
refrigerant. It is normal for a refrigerant sensor to sense refrigerant if placed too near the vent caps. If the seal allows refrigerant
vapor to pass, a sensor located at floor level 3 to 4 ft (0.9 to
1.2 m) from the sump vent cap will be quickly triggered as the
heavy refrigerant vapor will drop into the sump and flow out the
vent cap to floor level.
Table 1 — Control Settings
CONTROL
SETTING
English
Metric
36 F or 5 F lower than brine tem2.2 C or 3 C lower than brine temperature
perature
LOCATION
Low Chilled Water Temperature
Cutout
High Discharge Gas Temperature
Cutout
High Thrust Bearing Temperature
High Condenser Pressure Cutout
Compressor End Wall
220 F
104 C
Compressor Bearing Chamber
Instrument Panel
Low Cooler Pressure Cutout
Instrument Panel
85 C
13.0 kg/sq cm
0.14 kg/sq cm
Low Seal Oil Pressure Cutout
Instrument Panel
Low Bearing Oil Pressure Cutout
Instrument Panel
Auxiliary Oil Pump Differential
Pressure Control
Instrument Panel
185 F
185 psig
2 psi below design suction
pressure
Trip 11 psid
Trip 8 psig
Reset 13 psig
Stop 27 psid
Start 23 psid
Cooler Water Box
4
Trip 0.76 kg/sq cm
Trip 0.56 kg/sq cm
Reset 0.90 kg/sq cm
Stop 1.90 kg/sq cm
Start 1.60 kg/sq cm
Fig. 1 — Typical PLC Screen on Control Panel
Refrigerant R-134a requires the use of polyolester oil. Polyolester oils have a different molecular structure proprietary to
each manufacturer and have property differences that may or
may not make them suitable for operation in the 17DA chiller.
Carrier supplied oil has been laboratory tested by Carrier and
has been field tested in the 17DA chiller.
Ensure that there is adequate lubrication prior to the operation of all drive line components. Check the gear and drive
manufacturer’s instructions for proper initial lubrication
procedure.
Oil pressure from the main pump is set to maintain a pressure 35 psi (241 kPa) greater than the refrigerant pressure behind the shaft seal. If the oil pressure differential across the seal
falls below 23 psid (158 kPa), the auxiliary oil pump will start.
Table 2 — Pumpout System Ratings
PUMPOUT
SYSTEM
SETTING
Normal Condensing Pressure
Low-Pressure Cutout
High-Pressure Cutout
Relief Valve
a17-578
SATURATED CONDITIONS
(R-134a)
Maximum
Pressure
Temperature
psig kPa
F
C
146 1007
110
43
31.5
217
36
2
175 1207
121
49
185 1276
125
52
Charge Machine with Water — When the machine
has been proved leak tight and dry, it may be filled with water,
brine or other process fluid as the case may be. Vent all lines
and check for leaks.
It is advisable to install indicators on the coupling halves between the compressor and drive or gear to check for alignment
drift while charging with water and refrigerant. The weight of
these materials will always cause a shift in the position of the
machine components. Before and after indicator readings will
give a good clue to the direction final alignment should take.
Final Pre-Operation Alignment Check — Prior
to operating the compressor and speed increasing gear (if
used), coupling alignment and separation must be checked.
1. Ensure that coupling alignment is within coupling manufacturer's specified tolerances.
2. Refer to the coupling vendor’s drawing for hub separation tolerances.
3. When checking hub separation, electric motor shaft must
be in center position of shaft float or in magnetic center as
specified by the motor manufacturer.
Charge Machine with Oil — The 17DA chiller has an
integral lubrication system mounted on a common base with
the compressor. A parallel auxiliary oil pump system may also
be furnished. Charge the oil system with 35 gallons (132.5 L)
of oil, Carrier P/N PP23BZ106.
5
4. If realignment is required, follow instructions supplied by
coupling manufacturer. Carrier Standard Service Techniques, Form SM-15, Rev A, also details realignment
techniques.
Initial Compressor Operation
CAUTION
Do not apply power to any system or instrument that is
exposed to dehydration vacuum. Insulation breakdown
and serious damage can result.
Operate Drive — It is good practice to operate the drive
uncoupled from the compressor first and then couple it to the
compressor. Refer to the drive manufacturer’s instructions for
drive protection devices and settings. Check turbine overspeed
and confirm correct motor direction of rotation at this time. Reassemble coupling after operating the drive successfully.
NOTE: If there is a gear between the motor and compressor,
then it reverses rotation. Make sure that the gear output shaft is
turning in the correct direction.
1. Energize the control panel.
2. Place the guide vanes in MANUAL operation.
3. Manually energize the oil cooler solenoid and verify flow
through the oil cooler. Return the solenoid to automatic
control.
4. Observe whether the compressor shaft moves forward
(toward the suction) off the shutdown seal. Manually energize a compressor oil pump. Observe the shaft and verify that the seal movement indication changes on the PLC.
5. Turn off the oil pump and observe the shaft move back toward the driver. The PLC should indicate that the shutdown seal is closed. If the PLC does not indicate the shaft
position to be on the shutdown seal, terminate the startup.
Correct the shaft feedback before attempting a start to
prevent damage to the shaft and seal.
6. Place Compressor Oil Pumps into AUTOMATIC mode.
7. Place Capacity Control in MANUAL mode.
8. Open all valves to seal oil separator pot. Energize the separation pot heater if manually controlled. If the heater is
PLC controlled verify its operation after the compressor
starts.
9. Ensure that there is water in the cooling tower and that it
is operational.
Set Purge Valves — Open all the purge service valves.
Check Water Supply — Be certain that chilled water,
condensing water and oil cooler water supplies are available
and that pumps will run before operating compressor.
Check Air Supply (Pneumatic Machines) —
Make sure that control air is 35 psig (241 kPa).
START-UP
Pre-Operation Settings — Complete these settings
before starting compressor for first time.
Drive Operation — Refer to drive manufacturer's startup instructions. Complete drive starting requirements before
operating compressor.
Initial Refrigerant Charge
CAUTION
CAUTION
When liquid refrigerant R-134a is injected into a low vacuum of 29.48 in. (749 mm) mercury, it will immediately
flash to a gas at a temperature lower than –100 F (–73 C). It
is for this reason that water must be circulating before
charging liquid refrigerant. Non-circulating water would
quickly freeze and damage the machine. If an auxiliary
refrigerant storage tank (receiver) is furnished, then liquid
refrigerant may be charged directly into this evacuated
receiver without damage.
No brine or water over 100 F (37 C) can be allowed to flow
through the cooler. Damage to unit will result.
10. Open chilled and condenser water valves and start the
water pumps. If these are automatically controlled, verify
that they have opened and started.
11. Start the compressor and let it run for approximately
5 minutes. While it is running, observe bearing temperatures, vibration levels, and oil pressure. Listen for unusual
sounds.
12. Stop the compressor. During coast down again verify that
the compressor is rotating in the correct direction which is
counterclockwise if it is seen from the drive.
13. Observe the shaft movement to verify that the shutdown
seal has closed. If the shutdown seal is manually controlled, open the bleed valve on the inboard side of the
bearing chamber (inboard is the heat exchanger side.)
Large machines run with liquid refrigerant in the cooler so
refrigerant is charged into the cooler or low-pressure side of the
machine. For general instructions on how to handle refrigerant
refer to Carrier Standard Service Techniques, Form SM-1. Use
the Charging by Weight method, cross checking with the machine's refrigerant sight glass provided on the back of the cooler shell, and the suction pressure gage.
Charge refrigerant as follows:
1. Start cooler and condenser water circulating pumps.
2. Charge the first refrigerant in the vapor state, continuing
until the machine pressure exceeds 35 psig (241 kPa).
The refrigerant temperature corresponding to this pressure is high enough to prevent water freezing damage and
will also satisfy the refrigerant low-pressure cutout safety
switch setting (31.5 psig [217 kPa]).
3. Turn the refrigerant bottles or drums over and begin
charging the refrigerant in the liquid phase. Continue
charging liquid refrigerant until about 2/3 of the estimated
full load charge is in the machine.
Adjust Refrigerant Charge — To adjust the refriger-
ant charge, perform the following procedure.
1. Adjust control station to operate at MANUAL. Ensure
that the guide vanes are closed as indicated on the main
guide vane indicator.
2. The condenser liquid level control consists of a level
transmitter, the liquid line valve and a control program in
the PLC. As an initial set point, place the level setting
even with the condensed liquid thermowell. The well is
located on the same end of the vessel as the level transmitter. It can be on either side of the vessel. After the machine has reached stable operation, the level should be set
such that the condensed liquid temperature is 1 to 3° F
(0.5 to 1.6° C) below saturated condensing temperature.
6
The proportional band can be adjusted on the PLC to stabilize the level if necessary.
3. Start the compressor. Observe the machine's operation for
15 to 20 minutes before increasing the load. During this
period, make the following checks and adjustments:
a. Check oil pressure.
b. Adjust water flow thru oil cooler so that bearing
temperatures stay between 150 and 170 F (65 and
77 C) approximately.
c. Watch bearing temperatures carefully. This is the
first time that the machine has been run under
refrigeration load. Bearing temperatures may level
off at some temperature slightly higher than 170 F
(77 C) listed above. This may be the normal stable
condition for this bearing. High thrust bearing temperature will shut the machine down at 180 F
(82 C).
d. Watch the discharge temperature and if the temperature climbs past 150 F (65.5 C), open the guide
vanes in small steps of 5% or less until the discharge temperature starts to decrease.
4. Slowly open the guide vanes, by manual control, thus increasing the load. Do not exceed the current rating of the
electric motor. Watch for other signs of overloading a turbine or engine drive.
5. Add liquid refrigerant, trimming the charge off at the
point where the machine reaches design operating temperature and pressure conditions.
Realign component locations until angular and parallel
alignments are within coupling manufacturer's specified tolerances.
Dowel all equipment into place as soon as the hot alignment
check proves that the machine is within these running tolerances. See Carrier Standard Service Techniques, Form SM-15,
Rev A, for these operations.
Operational Testing — When the chiller is in operation, and it is time to set the flows and confirm that the machine
is operating according to design conditions, a heat balance
must be determined. In brief, a heat balance is the sum of the
energy being absorbed by the cooler plus the energy supplied
through the driver (turbine, motor) compared with the energy
being discharged through the condenser.
Cooler Tons + Motor Tons = Condenser Tons
When these two items are equal it is certain that the readings
and measurements are accurate. The motor kW must be corrected for motor efficiency and gear losses must be subtracted
from motor kW to get actual compressor input horsepower.
Motor kW is converted to equivalent tons by this formula:
Tons = kW / 3.515
Cooler and condenser tons: (for fresh water, specific heat
[sp ht] = 1 and specific gravity [sp gr] = 1)
Tons = (gpm * T * sp ht * sp gr) / 24
A perfect heat balance is 0, but this is practically impossible
to achieve. With laboratory quality instrumentation, less than a
2% heat balance at full load conditions should be achievable.
Greater than 5% should be regarded as very inaccurate and requires further investigation of the start-up conditions.
CAUTION
Instruct Customer Operator — Ensure the opera-
Excessive overcharge may cause liquid refrigerant carryover into the compressor, causing severe overload and possible compressor damage.
tor(s) understand all operating and maintenance procedures.
Point out the various chiller parts and explain their function as
part of the complete system.
CONTROL PANEL
1. Internal safeties
2. Communication with chiller controls
3. Starter operational sequence
4. Current and voltage monitor operation
VFD
1. Detailed description of component, section, purpose, and
operation
2. Control section processor and access to screens
3. Procedures to switch from bypass to VFD operation (if
bypass equipped)
6. Shut the machine off. When the refrigerant level settles
down, mark this optimum level on the sight glass. Maintain this shutdown level.
7. To determine the approximate refrigerant charge for the
machine, add the cooler charge to the applicable condenser charge as listed in Tables 3A and 3B.
Hot Alignment Check and Doweling — After the
machine has been running at about full load for 4 hours, its
components will have come up to steady state operating temperature conditions and the final hot alignment check may be
made.
Table 3A — Typical 17DA Cooler and Condenser Charges (R-134a) (lb)
COOLER
SIZE
61
63
65
67
71
73
75
81
82
83
84
85
86
87
88
90
15-FT TUBES
18-FT TUBES
22-FT TUBES
3,000
3,600
3,600
4,200
4,600
5,000
5,600
6,500
7,700
6,900
8,200
7,700
10,200
8,600
11,000
13,000
3,600
4,300
4,300
5,100
5,500
5,900
6,600
7,700
9,300
8,300
9,900
9,200
12,300
10,400
13,500
15,600
4,400
5,300
5,300
6,200
6,800
7,300
8,100
9,500
11,300
10,200
12,200
11,300
15,200
12,600
16,500
19,200
CONDENSER
SIZE
61
63
65
67
71
73
75
81
83
85
87
7
15-FT TUBES
18-FT TUBES
22-FT TUBES
2,000
2,000
2,500
2,500
2,600
2,600
3,100
3,500
4,000
4,600
4,500
2,400
2,400
3,000
3,000
3,100
3,100
3,700
4,100
4,700
5,400
5,300
2,900
2,900
3,600
3,600
3,800
3,800
4,500
5,000
5,800
6,700
6,500
Table 3B — Typical 17DA Cooler and Condenser Charges (R-134a) (Kg)
COOLER
SIZE
61
63
65
67
71
73
75
81
82
83
84
85
86
87
88
90
4.6 M TUBES
5.5 M TUBES
6.7 M TUBES
1362.0
1634.4
1634.4
1906.8
2088.4
2270.0
2542.4
2951.0
3495.8
3132.6
3722.8
3495.8
4630.8
3904.4
4994.0
5902.0
1634.4
1952.2
1952.2
2315.4
2497.0
2678.6
2996.4
3495.8
4222.2
3768.2
4494.6
4176.8
5584.2
4721.6
6129.0
7082.4
1997.6
2406.2
2406.2
2814.8
3087.2
3314.2
3677.4
4313.0
5130.2
4630.8
5538.8
5130.2
6900.8
5720.4
7491.0
8716.8
CONDENSER
SIZE
61
63
65
67
71
73
75
81
83
85
87
4. Location of isolation transformer, incoming switch gear.
5. Operation and servicing of the VFD Cooling system
(where applicable).
6. Interface with chiller control sequence.
7. Communication with chiller controls (hard wired, data
line)
STEAM TURBINE
1. Control interface with chiller controls
2. Turbine operation and maintenance training should be
done by the turbine manufacturer service representative.
GAS ENGINE
1. Control interface with chiller controls.
2. Engine operation and maintenance training should be
done by the engine manufacturer service representative.
OPERATING PROCEDURES
1. Starting and stopping of chiller including preparation of
turbine when applicable.
2. Valves that should be closed while machine is idle.
3. Move liquid refrigerant to storage tank for extended shutdowns. Vapor pressure in the chiller should remain above
atmosphere to prevent air from entering and to allow periodic leak checking.
LOG SHEETS
1. Information to be recorded and how often.
2. Spotting trends in the data for advanced warning of impending service needs.
4.6 M TUBES
5.5 M TUBES
6.7 M TUBES
908.0
908.0
1135.0
1135.0
1180.4
1180.4
1407.4
1589.0
1816.0
2088.4
2043.0
1089.6
1089.6
1362.0
1362.0
1407.4
1407.4
1679.8
1861.4
2133.8
2451.6
2406.2
1316.6
1316.6
1634.4
1634.4
1725.2
1725.2
2043.0
2270.0
2633.2
3041.8
2951.0
1. Energize controls. Investigate any alarm messages and
make appropriate corrections.
2. Check refrigerant level in cooler to be sure it is within operating limits (at least 1/2 sight glass). If level appears
low, check the subcooler sight glass to see if missing refrigerant is in the subcooler. This refrigerant will redistribute soon after machine starts.
3. Check oil levels for compressor, gear, drive, and other
auxiliary equipment.
4. Ensure that shutdown seal bleed valve (Fig. 3) is open.
5. Supply air to pneumatic controls. Check pressure and
cleanliness.
6. Start water pumps, if not controlled by the chiller.
7. Close shutdown seal bleed valve if it is a manual valve.
See Fig. 3. Valve must remain closed until the machine
has stopped and the shaft is at full stop.
8. Open isolation valves to refrigerant/oil separator.
9. If the chiller is a motor drive, press the START button and
then the machine will start.
10. If the chiller is a turbine drive, perform the following:
a. Push the START button on control panel. The
operator may now evacuate the surface condenser.
b. When the surface condenser is under vacuum, set
the governor for minimum speed. Open throttle
valve slowly and bring turbine up to minimum
speed. When the governor takes control, open the
throttle valve fully.
c. Run the turbine at minimum speed for the time
specified by the manufacturer. Adequate oil pressure must be present on all drive components. If
adequate oil pressure is not seen, shut down
machine.
d. Bring the turbine to operating speed. The machine
controls will assume control of the turbine and
begin to load the chiller.
11. Listen for unusual sounds which may indicate malfunction. If heard, shut down immediately.
12. Adjust oil cooling water to supply 120 F (49 C) oil to machine bearings. Observe oil temperatures on compressor,
gear, and drive until they have leveled off satisfactorily.
13. Start thermal purge unit.
Operator Duties
1. Become familiar with the chiller and related equipment
before operating the chiller.
2. Prepare the system for start-up, start and stop the chiller,
and place the system in a shutdown condition.
3. Maintain a log of operating conditions and document any
abnormal readings.
4. Inspect the equipment and make routine adjustments.
Maintain the proper oil and refrigerant levels.
5. Protect the system from damage during shutdown
periods.
Start Machine — These are general instructions for
17DA machines. Individual machines may vary in equipment
furnished. See Fig. 2 and 3.
8
9
TIME
Brine
Temp
Refrigerant
Water
Temp
CONDENSER
Shut
Press. Temp Down
Press. Temp
In Out
Level In Out
Refrigerant
COOLER
MACHINE MODEL NO.
Damper
Position
Fig. 2 — Refrigeration Log
Oil
Seal
Housing
Pressure
COMPRESSOR
Thrust Seal
End
End Supply
Bearing
Temp
MACHINE SERIAL NO.
REMARKS: Indicate shutdowns on safety controls, repairs made and oil or refrigerant added or removed. Include amounts.
DATE
Plant
Temp
A
B
D
OPERATOR
REMARKS
GAS ENGINE
Gas Pressure
Manifold Pressure
Jacket Water Temp
Oil Temp
C
PRIME MOVER*
STEAM TURBINE
Steam Pressure
Load Steam Pressure
Bearing Temp
Oil Pressure
Pressure
* ELECTRIC MOTOR
A Volts
B Amps
C Bearing Temp
D Oil Level
Temp
(reser- Level
voir)
GEAR OIL
REFRIGERANT TYPE
REFRIGERATION LOG CARRIER 17DA CENTRIFUGAL REFRIGERATION MACHINE
DATE
4
3
2
5
6
1
7
8
LEGEND
1 — Shaft End Labyrinth, Seal End
2 — Journal Bearing, Seal End
3 — Journal Bearing Labyrinth,
Seal End, Thrust End
4 — Seal Movement Switch
5 — Journal Bearing, Thrust End
6 — Shutdown Seal Bleed Line
(valve on opposite side)
7 — Shaft End Labyrinth, Thrust End
8 — Seal ring
9 — Balancing Piston Labyrinth
a17-572
9
Fig. 3 — Compressor Details
14. See Table 4 for normal operating ranges. Check these
characteristics hourly, recording readings in refrigeration
log. Refrigeration log should include all temperatures and
pressures mentioned above plus other machine history.
This important data helps service engineers determine
kind and frequency of service required. See your Carrier
Service Representative for refrigeration log forms (see
Fig. 2).
vane position. Operator must watch chilled water temperature
constantly when running machine in this manner.
Cold Weather Operation — Leaving condenser water
should be maintained at 65 F (18 C) minimum. Throttle condenser water flow or cycle cooling tower fans to suit.
Stop Machine
1. Check drive manufacturer's recommendations for adjustments required before shutdown.
2. Push STOP button. Drive will immediately slow down
with a change in sound level. The compressor should
come to rest within a minute or two. Check drive and
gear, when used, to be sure lubrication is maintained.
3. After compressor shaft has stopped rotating, shut off condensing water, chilled water and oil pumps.
4. Shut off cooling water to compressor oil, gear oil. and turbine oil coolers.
5. Shut off main steam (or gas) valve.
6. Open shutdown seal bleed valve (Fig. 3) after machine
completely stops rotating.
Table 4 — Normal Operating Ranges
ITEM
DESCRIPTION
1
Chilled Water Temperature
2
Condenser Entering Water
3
Compressor Supply Oil
4
Compressor Seal End Bearing
7
8
Compressor Drive End Journal
Bearing
Compressor Drive End Drive
Bearing
Condenser Temperature
Cooler Suction Temperature
9
Seal Oil Supply Pressure
10
Back of Seal Pressure
5
6
11
12
13
Thrust Bearing Oil Supply Pressure
Cooler Refrigerant Level
Speeds
Maximum Continuous Speed
Nominal Speed
RANGE
36-45 F
(2-7 C)
65-85 F
(18-29 C)
110-120 F
(43-49 C)
140-180 F
(60-82 C)
140-180 F
(60-82 C)
140-180 F
(60-82 C)
105 F (41 C) Avg
28 F (-2 C) min
35 psi (241 kPa)
greater than item
10
Approx. 2 lb (0.9
kg) higher than
suction pressure
18-22 psig
(124-152 kPa)
Varies with load*
Compressor
(17DA7,17DA8)
6350, 5300 rpm
(106, 88 r/s)
5350, 4510 rpm
(89, 75 r/s)
CAUTION
Open seal shutdown valve only after machine comes to a
full stop. If this valve is opened before the machine is fully
stopped, the Teflon shutdown seal surface will be damaged. A damaged seal will allow the full refrigerant charge
to be lost unless detected by the operator. If a hissing sound
is heard coming from the chamber or the odor of refrigerant is detected, immediately start the oil pump and inform
the servicing contractor. Leave the oil pump running until
the leak can be fixed.
7. Leave controls energized for except for seasonal shutdowns.
8. Leave oil separation tank heaters energized.
9. Isolate oil separation tank from the oil sump.
* Compare refrigerant level with optimum level when machine is shut
down.
Extended Shutdown
OPERATION
1. Pump refrigerant into storage tank and valve it off to prevent loss.
Manual Operation — Control machine manually at the
PLC by setting guide vanes on MANUAL and adjusting guide
10
LUBRICATION — Pumpout compressors are factory
charged with oil. The 5F20 open-drive is charged with 5 pints
plus 1 pint for the oil separator. Use Carrier oil part no.
PP23BZ103-001. This is a one gallon container. The oil level
should be at the center of the sight glass when the compressor
is not running. Always check the oil level before operating the
compressor.
CONTROL DESCRIPTION — The pumpout unit is
equipped with a low pressure safety, a high pressure safety, and
a time delay low oil pressure safety.
CONTROL SETTING — Set the safety switches using a metered air supply. The high-pressure switch setting can be
checked by operating the pumpout compressor while throttling
the pumpout condenser water. Exercise care when performing
the check in this manner. Watch the discharge pumpout discharge pressure gage to prevent exceeding the specified cutout
pressure.
2. If the machine will be exposed to freezing temperatures,
drain all water from cooler and condenser. Blow out oil
cooler lines to remove all traces of water. Leave water
box drains open until time to refill.
3. Deenergize the drive controls and refrigeration machine
control panels.
4. If refrigerant charge is to be left in machine, the shutdown
seal bleed valve must be left open to seal off the refrigerant side of machine. Best practice is to remove liquid refrigerant and pump vapor pressure down to be equal with
atmospheric pressure.
5. Protect drive equipment as outlined in drive manufacturer's instructions. Before putting machine back into operation after an extended shutdown period, it may be wise to
flush condenser and cooler water circuits with clean water to remove soft rust which may have formed.
Pumpout System Operation — The pumpout system operation permits transfer of refrigerant (liquid or gas)
from cooler to storage tank (or reverse). It can also be used for
machine evacuation and removal of contaminants.
Machines not containing refrigerant may be pressurized
with the pumpout unit. Since the pressurizing agent is unprocessed air, some moisture and contaminants can be introduced to
the machine by this method. Pressurizing with dry air or nitrogen is recommended. Procedures are based on typical piping
arrangements. See Fig. 4 for a typical piping schematic and
valve number designations.
The system consists of storage tank, pumpout compressor,
condenser, valves, and piping. Liquid refrigerant drains by
gravity if storage tank is below cooler. If tank is above cooler,
liquid is forced up by compressed refrigerant gas pressure. Gas
remaining in cooler is pumped out, condensed, and passed
through a high-pressure trap into the tank. Pressures may then
be equalized, by valve adjustment, permitting gravity flow of
refrigerant in opposite direction.
Compressor must rotate per arrow on crankcase for proper
lubrication.
Safety Device
Low Oil Pressure
Low Suction Pressure
High Discharge Pressure
Setting
14 psig (96 kPa)
31 psig (214 kPa)
165 psig (448 kPa)
The pumpout compressor is operated by a ON-OFF-AUTO
switch. The AUTO position enables the Low Suction Pressure
switch. This position is used to prevent a freeze-up when applying suction to a heat exchanger containing liquid refrigerant.
Otherwise, the ON position is used.
MACHINE AND STORAGE TANK EVACUATION (No
Refrigerant in System) — Perform the following procedure.
See Fig. 4 for valve numbers.
1. Place the control switch in the OFF position.
2. Close valves 2, 4, 9, 10, and 13.
3. Open valves 1, 3, 5, 6, 7, 8, 11, and 12.
Valve
Condition
1 2 3 4 5 6 7 8 9
O C O C O O O O C
NOTE: Numbers in schematic correspond to valve numbers in Pumpout System
Operation section and are used in conjuction with the tables and text to specify which
valves should be open and closed.
Fig. 4 — Pumpout System Schematic
11
10
C
11
O
12
O
a17-573
13
C
3. Operate the cooler water pump.
4. Open valves 3, 6, 7, and 9.
5. Close valves 2, 4, 5, 10 ,11, and 13.
4. Start the pumpout compressor (control switch at ON
position).
5. Operate pumpout compressor until suction gage reads
highest sustained vacuum (about 28 in. Hg VAC or
1
psia [6.9 kPa]).
6. Close valve 8.
7. Stop compressor (control switch at OFF position).
REMOVE AIR AFTER OPENING CHILLER TO ATMOSPHERE (Refrigerant Charge in Storage Tank) — Perform
the following procedure. See Fig. 4 for valve numbers.
1. Place the control switch in the OFF position.
2. Close valves 2, 4, 5, 9, 10, 11 and 13.
3. Open valves 1, 3, 6, 7, 8, and 12.
Valve
Condition
1 2 3 4 5 6 7 8 9
O C O C C O O O C
10
C
11
C
12
O
Valve
Condition
1 2 3 4 5 6 7 8
O C O C C C C C
9
C
10
C
11
C
12
O
13
C
Valve
Condition
Valve
Condition
5. Slowly open valve 5 and allow refrigerant vapor into the
chiller until chiller pressure increases to 35 psig (141 kPa)
for R-134a. Feed refrigerant slowly to avoid freeze-up.
6. Close valve 5.
7. Start the pumpout compressor (control switch in the
AUTO position).
8. When the cooler pressure is lower than storage tank pressure, open valve 11 and refrigerant will flow from the
storage tank to the machine.
9. Shut valve 11 when refrigerant level reaches the charge
level mark on the cooler sight glass.
10. Turn off the pumpout compressor (control switch in the
OFF position).
11. Close valves 3, 4, and 12.
TRANSFER REFRIGERANT CHARGE (From Machine
to Storage Tank Located Below Machine) — Perform the
following procedure. See Fig. 4 for valve numbers.
1. Vent storage tank to machine by opening valves 1, 2, 4,
and 12.
2. Open valves 11 and drain liquid from the cooler.
10
C
11
O
12
O
12
O
13
C
1 2 3 4 5 6 7 8 9
O O C C O O O C C
10
C
11
C
12
O
13
C
1 2 3 4 5 6 7 8 9
O C O C C O O C O
10
C
11
C
12
O
13
C
9. Run cooling water through the pumpout condenser.
10. Operate the pumpout compressor (control switch in the
ON position).
11. At 25 in. Hg VAC (2.5 psia, 17.21 kPa) in cooler, stop the
pumpout compressor. Close all valves and shut off
pumps.
PRESSURIZE MACHINE AND STORAGE TANK (No
Refrigerant in System) — Perform the following procedure.
See Fig. 4 for valve numbers.
1. Open valves 3, 4, 6, 7, 9, 11, and 13.
2. Close valves 1, 2, 5, 8, 10 , and 12.
13
O
Follow steps 5 and 6 carefully to prevent damage from a
freeze-up.
1 2 3 4 5 6 7 8 9
O O C O C C C C C
11
C
4. Operate the pumpout compressor (control switch in the
ON position).
5. When the storage tank pressure is less than machine pressure, open valve 11.
6. After the liquid has been transferred, stop the pumpout
compressor and the condenser water pump.
Continue to operate the cooler water pump.
7. Open valves 3, 6, 7 and 9.
8. Close valves 2, 4, 5, 10, 11, and 13.
CAUTION
Valve
Condition
10
C
6. Run cooling water through the pumpout condenser.
7. Operate the pumpout compressor (control switch in the
ON position).
8. At 25 in. Hg VAC (2.5 psia, 17.21 kPa) in cooler, stop the
pumpout compressor. Close all valves and shut off
pumps.
TRANSFER REFRIGERANT CHARGE (From Machine
to Storage Tank Located Above or Level with Machine) —
Perform the following procedure. See Fig. 4 for valve
numbers.
1. Operate the cooler and machine condenser water pumps.
2. Open valves 1, 2, 5, 6, 7, and 12.
3. Close valves 3, 4, 8, 9, 10 ,11, and 13.
4. Start pumpout compressor by putting control switch in
the ON position.
5. Operate pumpout compressor until suction gage reads
highest sustained vacuum (about 28 in. hg or 1 psia
[6.9 kPa]).
6. Close valve 8.
7. Stop compressor by placing the control switch in the OFF
position.
TRANSFER REFRIGERANT CHARGE (From Storage
Tank to Machine) — Perform the following procedure. See
Fig. 4 for valve numbers.
1. Place control switch in OFF position.
2. Operate cooler water pump and ensure that there is water
flow through the cooler.
3. Close valves 2, 4, 5, 6, 7, 8, 9, 10, and 11.
4. Open valves 1, 3, 12, and 13.
Valve
Condition
1 2 3 4 5 6 7 8 9
O C O C C O O C O
Valve
Condition
1 2 3 4 5 6 7 8 9
C C O O C O O C O
10
C
11
O
12
C
13
O
3. Operate the pumpout compressor (control switch in the
ON position) until desired pressure is reached. Do not exceed design pressure of vessels.
4. Stop the pumpout compressor (control switch in the OFF
position).
5. Close valve 13.
WARNING
Do not use refrigerant or air for leak testing. Personal
injury could result. Only use nitrogen for leak testing.
DISTILL REFRIGERANT CHARGE — Water, oil, and impurities can be removed from the refrigerant while transferring
the charge from storage tank to machine. Perform the following procedure. See Fig. 4 for valve numbers.
1. Operate the cooler and machine condenser water pumps.
13
C
12
2. Open valves 1, 2, 5, 6, 7, and 12.
3. Close valves 3, 4, 8, 9, 10 ,11, and 13.
Valve
Condition
1 2 3 4 5 6 7 8 9
O O C C O O O C C
10
C
11
C
12
O
chiller main control panel. Customer specifications may
require some or all of the sensors and safeties to be duplicated
by mechanical switches. For this reason both types of sensors
and safeties will be covered in the following procedures.
CHECK/CALIBRATE WATER TEMPERATURE SENSORS — The water temperature sensors are located in the outlet piping near the water nozzles.
1. Each sensor should be compared against a calibrated sensor in a calibration bath or dry block calibrator.
2. Compare the reading of the calibrated sensor with the
temperature reading on the PLC screen. Replace or calibrate the sensor as required.
3. Confirm that any set points on the PLC match the recommended alarm or trip points for the chiller.
CHECK REFRIGERANT LOW-PRESSURE CUTOUT —
The primary low-pressure cutout will be a function of the PLC
and the pressure will be transmitted to the PLC from a transducer. An optional mechanical secondary switch may also be
installed which will send an open-closed signal to the PLC.
1. Compare the reading of the cooler pressure transducer
with a test gage and/or the condenser pressure transducer
when the machine is not in operation. Confirm that the
correct cutout pressure is configured in the PLC.
2. The chilled water low-temperature cutout set point must
be temporarily set low enough that the refrigerant lowpressure cutout will react first. A mechanical low chiller
water temperature switch should be jumpered for the duration of the test.
3. Start the machine and observe both chilled water temperature and refrigerant temperature.
4. Slowly reduce the chilled water temperature control
point. Watch the thermometer in the leaving chilled water
line and/or the leaving chilled water temperature display
on the PLC screen. Do not allow chilled water temperature to drop below 35 F.
5. The machine should shut down when refrigerant temperature reaches one degree below design suction temperature or 28 F (-2.22 C) minimum (chilled water duty).
6. Restore the chilled water low-temperature cutout to its
normal set point. Remove the jumper on the mechanical
chilled water low-temperature cutout switch.
CHECK CONDENSER HIGH-PRESSURE CUTOUT —
This PLC function and optional mechanical pressure switch
senses condenser gas pressure and shuts down the compressor
when the condenser pressure exceeds 165 psig (1138 kPa) for
R-134a or 275 psig (1896 kPa) for R-22. Do not attempt to test
this safety by forcing the condensing pressure to rise during
machine operation.
1. Compare the reading of the condenser pressure transducer with a test gage and/or the cooler pressure transducer
when the machine is not in operation. Confirm that the
correct cutout pressure is configured in the PLC.
2. To check a mechanical cutout switch, first turn off the
control power.
3. Use an air or nitrogen supply which can be regulated to
the desired pressure.
4. Check the control with an ohmmeter to determine if the
switch has opened when the desired pressure is reached.
Adjust as necessary.
CHECK AUXILIARY OIL PUMP CONTROL — The purpose of the auxiliary oil pump is to take over the job of supplying lubricating oil at the required pressure to the bearings and
the seal in the event that the main oil pump loses pressure. The
auxiliary oil pump should start before the machine trips on low
oil pressure. The pressure being measured is the differential
pressure between the machine internal pressure on the
13
C
4. Operate the pumpout compressor (control switch in the
ON position).
5. When all of the liquid refrigerant has been removed from
the storage tank, stop the pumpout compressor and close
valves 1, 2, 5, 6, 7, and 12 (all valves closed).
6. Open valve 10 and plugged drain connection 14. Drain
water and impurities. Do not allow storage tank pressure
to drop below 0 psig.
7. Close valve 10 and plugged drain connection 14.
8. If, after distilling the refrigerant, there is excess refrigerant in the cooler over the normal operating charge, then
return the excess to the storage tank. Follow the procedure Transfer Refrigerant from Machine to Storage Tank
on page 12.
CHARGE REFRIGERANT — The pumpout unit can aid in
charging refrigerant into a dehydrated machine. Perform the
following procedure. See Fig. 4 for valve numbers.
1. Follow the procedure for Machine and Storage Tank
Evacuation (No Refrigerant in System) on page 11 to remove any non-condensable gases, if present.
2. Using temporary charging lines, connect the vent of the
refrigerant supply cylinder to valve 13 and the cylinder
liquid drain to valve 10. Purge the lines as final connection is made to the valves.
3. Open valves 2, 4, 5, 6, 7, 10, and 13.
4. Close valves 1, 3, 8, 9, 11, and 12.
Valve
Condition
1 2 3 4 5 6 7 8 9
C O C O O O O C C
10
O
11
C
12
C
13
O
5. Drain any remaining liquid by raising cylinder pressure
above storage tank pressure. Close valve 4 and operate
pumpout compressor with control switch in ON position.
MAINTENANCE
The primary controls, both operating and safety are now incorporated into the programmable logic controller (PLC)
which is incorporated into the chiller main control panel. Customer specifications may require some or all of the sensors and
safeties to be duplicated by mechanical switched. For this reason both types of sensors and safeties will be covered in the following procedures.
Weekly Maintenance
CHECK OIL LEVEL — Mark edge of sight glass at normal
oil level using grease pencil. Record date and amount of oil
added in refrigeration log.
CHECK PURGE FREQUENCY — Operate the purge only
when there is air in the system as indicated by the pressure in
the purge chamber when the machine is in operation. When
purge chamber pressure is within 8 psid of condenser pressure,
the vent valve can be opened to bleed air from the chamber.
Close the valve when the differential is higher than 16 psid.
WATER IN PURGE WATER CHAMBER — Refrigerants
R-22 and R-134a hold a greater percentage of water in the liquid state than in the vapor state. As a result, a typical condensing purge does not separate water from refrigerant. Alternate
methods such as refrigerant analysis are used to detect water in
these refrigerants.
Yearly Maintenance
NOTE: The primary controls, both operating and safety, are
now incorporated into the PLC, which is incorporated into the
13
refrigerant side of the seal and the oil supply being controlled
by the differential pressure regulator. The pressure being supplied to the seal is maintained at 35 psid above the pressure on
the refrigerant side of the shaft seal. The auxiliary oil pump
should start if the differential pressure falls to or below 23 psid.
Lower the oil pressure by adjusting the differential oil pressure regulator until the oil pressure drops to 23 psid. On completion of the test, reset the oil pressure regulator to its normal
setting of 35 psid. The auxiliary pump will stop when the oil
pressure rises above 27 psid.
CHECK SEAL OIL DIFFERENTIAL PRESSURE
TRANSDUCER — This function shuts down the compressor
if the seal oil pressure differential drops below its fault limit.
The transducer should be checked for proper calibration by
comparing against a known pressure gage. If two individual
single input transducers are used instead of a differential transducer, the measured pressures will be compared by the PLC to
calculate the differential pressure reading.
CHECK THRUST BEARING OIL PRESSURE TRANSDUCER — This function shuts down the compressor if the
thrust bearing oil pressure drops below its fault limit. The thrust
bearing is in the ambient atmosphere so the oil pressure is referenced to ambient pressure. The transducer should be checked
for proper calibration by comparing against a known pressure
gage and the set point should be checked on the PLC screen.
CHECK DISCHARGE GAS HIGH-TEMPERATURE
CUTOUT — This function shuts down the compressor if the
compressor discharge gas temperature exceeds its fault limit.
The sensor is located in a temperature well in the back wall of
the compressor. It is located to the immediate right of the bearing chamber on the 7 frame compressor and to the immediate
left of the bearing chamber on the 8 frame compressor. The
sensor should be compared against a calibrated sensor in a calibration bath or dry block calibrator.
CHECK THRUST BEARING OIL HIGH-TEMPERATURE CUTOUT — This function shuts down the compressor
if the temperature of the oil leaving the compressor exceeds its
fault limit. The sensor is located in the bearing chamber and is
inserted into the leaving oil temperature well that is an integral
part of the thrust bearing housing.
The sensor should be compared against a calibrated sensor
in a calibration bath or dry block calibrator.
CHECK SHAFT MOVEMENT SWITCH — The shaft
movement switch will shut down the compressor if the thrust
bearing has been damaged. This protects the impeller from
damage. The switch is mounted inside the bearing chamber at
splitline level. It is actuated by a trigger screw that protrudes
from the main shaft.
With the shaft in the thrust position, the clearance between
the screw head and the switch should be 0.014 to 0.015 in.
(0.356 to 0.038 mm) as shown in Fig. 5.
Check the integrity of the wiring and connections between
this switch and the bulkhead terminals. If this switch has
opened during compressor operation, do not restart the machine. Contact a Carrier service representative immediately.
CHECK COOLER AND CONDENSER MINIMUM
FLOW PROTECTION — Flow monitoring devices are specified per job, however the common purpose is to prevent damage to the chiller due to insufficient water flow. With the chiller
not in operation, reduce water flow to each vessel in turn until
the low flow cutout function activates. Confirm the flow rate is
correct. Calibrate the monitor(s) as required.
CHECK AUXILIARY INTERLOCKS — Refer to the job
wiring drawing for interlock wiring. Interlocks and safety controls must deenergize the main holding coil, turbine solenoid
trip, etc. to shut down the refrigeration compressor under unsafe conditions. Serious damage to the machine could result if
safety devices are bypassed.
a17-574
Fig. 5 — Shaft Movement Switch Detail
CHECK CONDENSER SUBCOOLER LEVEL CONTROL — The purpose of this function is to control the liquid
valve in the condenser drain line. The liquid level in the condenser shell should be as close as possible to the deck that divides the condenser section from the subcooler section. When
the level is correct and the chiller is running near design conditions, the correct level should result in a temperature reading of
0 to 2° F below saturated condensing temperature at the condensed liquid thermowell near the subcooler inlet.
The control consists of a level transmitter with the PLC supplying the signal to the liquid valve. A self-contained pneumatic or electronic level control may also be supplied which controls the liquid valve directly.
To calibrate either type of control, initially set the level so
that the sight glass or transmitter output indicates that the level
is approximately at the level of the condensed liquid thermowell. Make final adjustment based on the condensed liquid
temperature. If the temperature is too low, drop the level. If the
temperature is too high, raise the level.
CHECK COMPRESSOR GUIDE VANE CONTROL —
The standard guide vane actuator is a pneumatic piston actuator controlled by a built-in positioner. The positioner receives a
3 to 15 psig signal. The signal comes from an electric-to-pneumatic transducer controlled by the PLC. The actuator is
equipped with a solenoid operated “quick-dump” valve. This
allows the vanes to immediately close on compressor shutdown and prevents the guide vanes from operating until the
chiller is fully in “run” condition. The solenoid is controlled by
the PLC.
The maximum guide vane opening should be set in the PLC
such that the vanes stop opening when the position indicator
beneath the actuator points to 90.
Set the supply air pressure regulator for 80 psig minimum,
100 psig maximum. The cushion air supply to the bottom of
the piston should be set for 40 psig. The cushion air pressure
may be varied to suit job conditions. Cushion air pressure closes the guide vanes. If an adjustment is made it must be proven
that the vanes can readily close before the compressor is started. Increasing cushion air pressure slows the vane opening
speed and increases the vane closing speed. Ensure that the air
supply is filtered and dry.
CHECK OIL PRESSURE REGULATORS — Maintain by
making proper adjustments and providing clean and ample oil
supply. See Oil Cycle section on page 18 for more information.
Thrust Bearing Oil Pressure Regulator — The regulator reduces the main oil pump discharge pressure to 18 psig for drive
end journal bearing and thrust bearing lubrication.
Differential Back-Pressure Regulator — The regulator maintains a differential pressure of 35 psid between oil pump discharge pressure and pressure in refrigerant side, back-of-seal
section of compressor. Excess oil is relieved directly to oil
sump. This control maintains oil supply pressure higher than
14
2. Remove evacuator valve and float assembly.
3. Clean refrigerant float chamber.
4. Operate float valve through full travel. Valve must move
freely without binding.
5. Examine valve plunger and seat for dirt and wear. Replace plunger and seal assembly if worn.
6. Reinstall components using new sealing gaskets.
7. Check 1/16-in. orifice in strainer/orifice assembly (Item
6, Fig. 6). Clean strainer (Item 7, Fig. 6).
8. Replace the strainer.
machine refrigerant pressure, so that any oil leakage through
the 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 temperature and investigate cause when evidence is found, clean
and remake the connection:
• Operation of cooling fans
• Dirt, corrosion, carbon tracking and oily contamination of
mechanisms and contacts
• Soot, stained areas, evidence of smoke must be investigate
before 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 overtravel
• Circuit breaker calibration
• Operation of all safeties and interlocks
• Calibration of safeties
• Isolation switch operation
COMPRESSOR BEARING MAINTENANCE — The key
to good bearing maintenance is proper lubrication. Use the
proper grade of oil, maintained at recommended level, temperature, and pressure. Inspect the lubrication system regularly and thoroughly.
CHANGE OIL AND OIL FILTER — Periodic oil samples
should be used as guidance regarding the necessity of oil
changes. Contaminants and evidence of deterioration by the
presence of acid are of primary importance. Synthetic oil does
not break down and lose viscosity over time under normal
operation.
The oil filters should be changed at a minimum of one year
intervals. The oil charge is 35 gallons. Carrier supplies suitable
oil 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 located
beneath the pump motor end. Use bottom plug.
2. Remove plug. Drain oil into suitable container and replace plug.
INSPECT COOLER TUBES — Inspect tubes and clean at
the end of the first operating season. Condition indicates frequency of cleaning required in future and also whether or not
water treatment is required in chilled water circuit.
A yearly eddy current test of the heat exchanger tubes will
reveal most damage and enable corrective action to prevent an
eventual failure.
INSPECT CONDENSER TUBES — Inspect tubes and clean
yearly or more often if water is contaminated. Higher than normal condenser pressure usually indicates dirty tubes. Air in machine also results in high pressures.
Open systems and make-up water result in condenser tubes
fouled by scale and algae. A specialist should analyze water
and recommend treatment required.
Brushes designed to prevent scraping of tube walls are sold
through Carrier Service Center. Hard scale may require chemical cleaning.
INSPECT PURGE RECOVERY UNIT — Close purge service valves. This unit handles corrosive mixtures at their highest concentration and protects machine. Keep it in good operating condition. See Fig. 6 for purge evacuator assembly components. Proceed as follows:
1. Remove purge cover from purge evacuator assembly.
General Maintenance
REFRIGERANT LEVEL — Excessive refrigerant in cooler
causes liquid droplets to be pulled into compressor suction and
requires excess power for tonnage produced.
Too little refrigerant reduces the number of tubes that cool
the water, causing inlet guide vanes to open, thus further reducing cooler pressure. The machine may shut down on refrigerant
low-pressure cutout even though chilled water temperature is
too high.
Proper refrigerant charge is indicated when difference between leaving chilled water temperature and cooler temperature reaches design conditions, or becomes a minimum at design load conditions. To determine the approximate refrigerant
charge for your machine, add the cooler charge to the applicable condenser charge as listed in Table 3.
The optimum operating charge for the machine must be determined by adjusting the charge during operation at or near
full design load. See Charge Refrigerant in the Start-up section
of this manual. The optimum charge level should be marked on
the cooler level sight glass. This allows the correct amount of
refrigerant to be returned to the machine after service or a seasonal shutdown.
Refrigerant loss is always due to leaks, since the 17DA machine operates at pressures above atmospheric. Check over the
machine frequently with approved refrigerant leak-detecting
equipment. Repair all leaks.
LEAK TESTING — Since HFC-134a is above atmospheric
pressure at normal operating temperatures, effective leak testing can be done with refrigerant in the machine. Refrigerant
may have to be pumped out to storage tank before leaks are
repaired.
If the machine is empty of refrigerant, proceed as follows:
1. Use HFC-134a as a tracer gas. Pressurize the machine
with HFC-134a vapor to 20 psig (138 kPa).
2. Complete the pressurization using a dry gas (nitrogen) to
90 to 100 psig (620 to 690 kPa). Maximum test pressure
is 150 psig (1034 kPa). Never use air to pressurize machine for a leak test. A serious explosion may result.
3. Leak test using an electronic leak detector suitable for
HFC-134a. Test all joints and flanges, including the
pumpout and purge units. Repair all leaks and repeat tests
until machine is tight. A heavy concentration of refrigerant in the machine room decreases leak testing efficiency.
Ventilate the room well with ample fresh air before attempting 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) mercury vacuum on machine.
3. Valve machine off. Turn vacuum pump off. Stop water
pumps. Leave oil pump running.
4. A vacuum loss rate of 0.05 in. (1 mm) mercury per 24
hours or less indicates acceptable leak tightness.
15
3/4-IN. INSULATION
PURGE SYSTEM
VALVE ASSEMBLY
1
2
3
4
5
6
7
8
9
10
11
12
EVACUATOR ASSEMBLY
a17-577
—
—
—
—
—
—
—
—
—
—
—
—
LEGEND
Purge Connection
Shutoff Valves
Strainer
Orifice
Condensing Chamber
Condensing Chamber Pressure Gage
Non-Condensable Vent Valve
Cooling Coil
Refrigerant Chamber and Purge Float Valve
Refrigerant Sight Glass
Water Chamber and Hand Drain Valve
Water Sight Glass
Fig. 6 — Purge Cycle Schematic Piping
BREAKING VACUUM — When breaking vacuum during
leak testing or other service work, always use dry refrigerant or
other form of dry gas; i.e., nitrogen or air.
The use of dry gas to break machine vacuum is especially
important in areas of high humidity to prevent corrosion damage due to water condensing in refrigerant spaces within
machine.
PREPARING MACHINE FOR CHARGING REFRIGERANT — After servicing machine and checking the leakage
rate, apply a vacuum pump and pull machine pressure down to
0.15 in. (4 mm) mercury absolute pressure or less. Valve off
and charge with refrigerant.
After the first few minutes of operation, residual air not removed by the vacuum pump will collect in the condenser shell
where it will be pulled off by the purge sampling tube.
CHILLER DEHYDRATION — Dehydration is recommended if the chiller has been open for a considerable period of time,
if the chiller is known to contain moisture, or if there has been a
complete loss of chiller holding charge or refrigerant pressure.
CAUTION
Do not start or megohm-test the compressor motor or oil
pump motor, even for a rotation check, if the chiller is
under dehydration vacuum. Insulation breakdown and
severe damage may result.
Dehydration can be done at room temperatures. Using a
cold trap (Fig. 7) may substantially reduce the time required to
complete the dehydration. The higher the room temperature,
the faster dehydration takes place. At low room temperatures, a
very deep vacuum is required to boil off any moisture. If low
ambient temperatures are involved, contact a qualified service
representative for the dehydration techniques required.
Perform dehydration as follows:
1. Connect a high capacity vacuum pump (5 cfm [.002 m3/s]
or larger is recommended) to the refrigerant charging
valve (Fig. 4, item 10). Tubing from the pump to the chiller should be as short in length and as large in diameter as
possible to provide least resistance to gas flow.
2. Use an electronic vacuum indicator or a wet bulb vacuum
indicator to measure the vacuum. Open the shutoff valve
16
3.
4.
5.
6.
7.
to the vacuum indicator only when taking a reading.
Leave the valve open for 3 minutes to allow the indicator
vacuum to equalize with the chiller vacuum.
If the entire chiller is to be dehydrated, open all isolation
valves (if present).
With the chiller ambient temperature at 60 F (15.6 C) or
higher, operate the vacuum pump until the manometer
reads 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 below
33 F (0.5 C) on the wet bulb vacuum indicator. At this
temperature and pressure, isolated pockets of moisture
can turn into ice. The slow rate of evaporation (sublimation) of ice at these low temperatures and pressures greatly increases dehydration time.
Filling the heat exchanger tubes with warm water (100 F
[38 C] or cooler) will warm any moisture clinging to the
tubes and thus will increase the evaporation rate. If the
waterbox covers are open warm air can be blown through
the tubes. Again observe the 100 F (38 C) limit.
Valve off the vacuum pump, stop the pump, and record
the instrument reading.
After a 2-hour wait, take another instrument reading. If
the reading has not changed, dehydration is complete. If
the reading indicates vacuum loss, repeat Steps 4 and 5.
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, and
repeat dehydration.
Table 5 — Clearances
ITEM
(Fig. 4)
DESCRIPTION
Shaft End Labyrinth
Seal End
Thrust End
Journal Bearing
Labyrinth
Seal and Thrust End
Impeller Eye
Balancing Piston
Journal Bearings
Thrust Clearance
Thrust Disc Face
Runout
Seal Ring
Seal Shoulder to Seal
Housing Face
Shaft Movement
(Safety) Switch
Seal Movement
(Safety) Switch*
DIMENSION
(in.)
Min
Max
MEASURE
TYPE
1
8
.008
.001
.011
.003
Dia.
Dia.
3
.005
.009
Dia.
—
10
2, 5
—
.026
.032
.0035
.008
.034
.036
.0055
.012
Dia.
Dia.
Dia.
Axial
7
.0005 TIR
Axial
9
.0015
.004
Dia.
—
50/
61/
Axial
1
64
1
64
Fig. 5
.014
.018
Fig. 5
4
.020
.025
Axial
TIR — Total Indicator Reading
GENERAL DATA
Machine Nameplate — The machine nameplate with
machine serial number and machine designation is located on
the safety panel. These numbers include information about the
machine. For example, 17DA81 indicates:
17 - Open-drive centrifugal refrigeration compressor
DA - Single-stage
81 - Compressor size
The overall assembly as well as each major component has
a serial number. When corresponding with your Carrier representative, always give machine designation, machine serial
number, and component serial numbers.
Refrigerant Properties — Refrigerant is relatively
safe. The sweet-smelling vapor is nonflammable and nontoxic.
Heavy concentrations may cause dizziness, headache, and loss
of consciousness. When subjected to flame, refrigerant breaks
down into toxic gases. Avoid breathing fumes.
Refrigerant dissolves oils and destroys natural rubber and
all components containing rubber. Carefully selected neoprenes are safe to use.
Air or water floats on top of refrigerant in gas or liquid state
respectively. Being heavier than air, refrigerant will settle in all
low places. See Tables 6A and 6B for refrigerant temperature
vs pressure (saturated) relationships.
a19-661
Fig. 7 — Dehydration Cold Trap
REMOVING REFRIGERANT — Machines with refrigerant are usually provided with a storage tank and pumpout unit
to permit refrigerant removal when performing service work.
Refer to Pumpout System Operation section.
WATER TREATMENT — In hard water areas, the condensing water system must be cleaned frequently (at least yearly) to
prevent a rise in condenser pressure. Proper water treatment
and 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 is
recommended that a reliable water treatment specialist be consulted and a sample of the condenser water tested to determine
the type of water treatment required.
CLEARANCES — Clearances for compressor components
shown in Fig. 4 and listed in Table 5 are a guide to be used
when checking or fitting a replacement part.
GEAR AND DRIVE — Refer to gear and drive manufacturer's instructions for maintenance requirements.
PUMPOUT SYSTEM — Refer to Carrier Service Instructions for 5F,H condensing units for maintenance.
Relief Valve Assembly — The relief valve assembly is
located on the refrigerant storage tank. It prevents dangerous
high pressure from developing within the machine from fire or
any other reason.
System Components — The system components consist of the following:
• Cooler - Heat exchanger which cools "brine" passing
through the tubes by evaporation of the refrigerant in which
tubes are immersed.
• Compressor - Machine which compresses the evaporated
refrigerant and discharges it to the condenser.
• Condenser - Heat exchanger which liquefies the evaporated
refrigerant discharged into it from the compressor.
• Purge Recovery Unit - A small condensing unit with separator which continuously extracts gas from the top of the condenser and purifies it by removing air which may be
present.
17
Since the coldest condenser water flows through the subcooler tubes, the temperature of the refrigerant is reduced as
much as possible before it enters the cooler.
When the refrigerant clears the refrigerant flow valve and is
once again at cooler pressure, the refrigeration cycle is complete.
• Controls - Instruments which control the brine temperature,
protect the various elements of the machine, and automatically start and stop the compressor. When specified, additional controls for automatic operation of interconnecting
equipment such as fans and pumps are furnished.
• Drive - Prime mover which supplies the power to drive the
compressor.
• A refrigerant pumpout and storage unit is usually furnished
with this equipment. The refrigeration cycle covers the first
three major components; the others are described in other
portions of this manual.
Oil Cycle — See Fig. 9. External, positive displacement oil
pump (Item 9) mounted on reservoir (Item 11) discharges to
cooler (Item 7) and filter (Item 6). Auxiliary oil pump (Item 10)
is provided to maintain continuous lubrication during
emergencies.
Supply oil temperature is read on thermometer (Item 5) located in line between cooler and filter. Oil temperature is controlled by regulating water flow to the cooler. Differential pressure regulator (Item 8) maintains seal and seal end journal
bearing (Item 15) oil pressure at 35 psid (241 kPa) above backof-seal refrigerant pressure. Seal oil low pressure cutout (Item
1) shuts down compressor if seal oil pressure drops below cutout pressure. Seal end journal bearing temperature is read on
thermometer (Item 14).
Pressure regulating valve (Item 4) regulates oil supply pressure to thrust bearing and seal-end journal bearing (Item 15).
Bearing oil pressure is read on bearing oil supply pressure gage
(optional). Thrust bearing oil low-pressure cutout safety function shuts down compressor if bearing oil pressure drops below
cutout pressure.
Oil from the seal and bearings returns by gravity flow thru a
common drain line to the oil reservoir. Oil leakage thru the seal
to the refrigerant side drains to a separation tank (Item 13)
where absorbed refrigerant is driven from the oil by a small
heater.
The refrigerant gas is vented to the compressor suction. The
oil is returned to the reservoir thru a float valve (Item 12) which
controls the oil level in the separation tank.
Refrigeration Cycle — See Fig. 8. In the cooler, heat is
transferred from water flowing thru the tubes to cold refrigerant around the tubes. The cooler refrigerant temperature corresponds to cooler pressure as listed in Tables 6A and 6B. Heat
extracted from the water evaporates the liquid refrigerant, releasing large volumes of refrigerant gas which pass into the
compressor.
Eliminators in the top of the cooler prevent any liquid refrigerant from being carried over into the compressor.
The compressor impeller raises the gas from cooler pressure
up to condenser pressure. Gas flow into the compressor is controlled by adjusting the suction inlet guide vanes and the variable diffuser width. This controls cooler pressure and, therefore, machine capacity.
In the condenser, heat is transferred from the high-pressure
refrigerant gas to water flowing through the tubes. The gas condenses on the tubes and the liquid drains in to the condenser
subcooler section. A subcooler level control keeps the subcooler tubes covered with refrigerant and provides an effective liquid seal, preventing refrigerant gas flow from high-pressure to
low-pressure side of the machine.
a17-575
Fig. 8 — Refrigeration Cycle
18
17
18
1
PT
15
16
2
PT
3
PT
4
6
5
8
14
9
13
12
7
11
10
1
2
3
4
5
6
7
8
9
—
—
—
—
—
—
—
—
—
LEGEND
Seal Oil Supply Pressure Transmitter
10
Back-of-Seal Oil Pressure Transmitter
11
Bearing Oil Supply Pressure Transmitter
12
Low Pressure Regulator
13
Oil Supply Temperature Gage
14
Oil Filter
15
Oil Cooler
16
Differental Pressure Regulator
17
Main Oil Pump
18
—
—
—
—
—
—
—
—
—
Auxiliary Oil Pump
Oil Resevoir
Seal Oil Return Float Valve
Oil/Refrigerant Separator
Seal-End Journal Bearing Thermometer
Seal and Seal-End Journal Bearing
Seal Movement Switch
Thrust Bearing and Drive-End Journal Bearing
Shutdown Seal Automatic and Manual Bleed Valves
a17-576
Fig. 9 — Schematic Oil Diagram
The condensed vapors fall in the condensing chamber (Item
5) and separate by gravity. Refrigerant collects in the lower
chamber (Item 9) and water in the upper chamber (Item 11). As
the refrigerant level in the lower chamber rises, float valve
(Item 9) opens and refrigerant flows through valve (Item 2) to
the cooler. Refrigerant vaporized in the cooling coil also returns to the cooler.
Air and any other non-condensables accumulate in the condensing chamber. As the pressure in the chamber rises to approach within 8 psi of the chiller condenser pressure, the noncondensables must be vented through the non-condensable
Vent valve (Item 7). Watch the condensing chamber gage (Item
6), and close the vent valve when the chamber pressure drops
to 16 psi below chiller condenser pressure.
Auxiliary oil pump, if used, operates when seal oil and
back-of-seal oil pressure difference is less than 23 psi. Control
is located on machine safety panel.
Purge Cycle — See Fig. 6. Non-condensable gases, water
vapor, and refrigerant vapor pass from top of machine condenser through strainer (Item 3) and orifice (Item 4) to purge condensing chamber (Item 5). Water and refrigerant vapors are
condensed by cooling coil (Item 8) which is supplied with filtered refrigerant (Item 3) through orifice (Item 4) in machine
condenser liquid line.
NOTE: Refrigerants HCFC-22 and HFC-134a hold a greater
percentage of water in the liquid state than in the vapor state.
As a result, HCPC-22 and HFC-134a refrigerants will not
release water in the purge. Use another method to detect water
in these refrigerants.
19
can be done, stop the machine until load on the system
increases.
CONDENSER WATER TEMPERATURE IS TOO
HIGH — As machine cooling load drops below design, entering condenser water temperature must also drop. The ability of
a centrifugal compressor to produce pressure is directly related
to the amount of gas passing through it. Lower the condenser
water pressure or temporarily raise the chilled water set point.
FOULED TUBES IN EITHER HEAT EXCHANGER —
Clean the tubes.
LOW
WATER
FLOW
IN
EITHER
HEAT
EXCHANGER — Condenser water should remain at design
flow. Cooler water flow can be varied to meet system needs.
The allowable minimum must be determined for each machine.
If surge occurs the load on the machine may seem sufficient
when it is not unless flow rate and delta T are both checked.
VARIABLE SPEED DRIVE OPERATING TOO
SLOWLY. — When leaving chiller water temperature is controlled by varying the compressor speed, it is possible that during low load conditions the rpm required for the capacity may
be too low to maintain the required lift. In this case, the speed
must be temporarily increased and the guide vanes used to control the water temperature. Conditions allowing return to speed
control are indicated by the full opening of the guide vanes.
During shutdown all pressures equalize and refrigerant will
not separate from air in the purge. Do not vent the purge when
the machine is not running.
TROUBLESHOOTING
When troubleshooting the 17DA machine, check the PLC
display on the control panel first. Messages on the main screen
will indicate the fault or faults, plus further information can be
found on the screens applicable to that function or functions related to the fault.
Compressor Will Not Start
SAFETY SWITCH MALFUNCTION — There are standard
mechanical switches on the chiller along with sensors that provide information to the PLC. Two standard sensors that are always provided are the seal movement safety switch and the
shaft movement safety switch. If either switch or its wiring is
open circuited, then the PLC will show an alarm.
Mechanical switches for various temperatures and pressures
may be provided in addition to the sensors of the PLC, if specified by the customer. These mechanical switches are also connected to PLC inputs and the switch or circuit that is open will
be reported by the PLC.
DRIVE MALFUNCTION — Safety switches and sensors on
the motor, speed increaser or turbine normally are connected to
and identified by the PLC. Variable frequency (speed) drives
(VFD) will have their own display panel. Starters of the size
used for the 17DA chillers generally have monitoring instruments that will provide information on internal problems, problems with incoming power, etc.
Chilled Water Temperature Too High — Following are some of the causes of a high chilled water temperature
and corrections associated with them.
CHILLED WATER SET POINT TOO HIGH — Lower set
point.
MOTOR IS LOAD LIMITED BELOW THE REQUIRED
POWER TO MAINTAIN CHILLED WATER TEMPERATURE — Reset limit.
CHILLED WATER SET POINT HAS BEEN OVERRIDDEN BY THE BUILDING CONTROL SYSTEM —
Check settings of building control system.
GUIDE VANES NOT FULLY OPENING (for reasons other
than the above)
• Check supply air pressure to the actuator
• Check the instrument air signal
• Guide vane travel limited in the PLC
• Defective electronic-to-air signal transducer
• Guide vanes mechanically stuck
• Actuator or positioner malfunctioning
• “Quick dump” solenoid operated valve on the positioner is
leaking
HIGH CONDENSER PRESSURE — See section entitled
Condenser Pressure Too High.
COOLER WATERBOX DIVISION PLATE GASKET OUT
OF PLACE — Fix gasket.
LEAVING CHILLED WATER SENSOR DEFECTIVE —
Replace sensor.
EXCESSIVE WATER FLOW THROUGH THE
COOLER — Check chiller configuration.
EXCESSIVE DIFFERENCE BETWEEN CHILLED
WATER TEMPERATURE AND REFRIGERANT TEMPERATURE
• Low refrigerant charge
• Fouled cooler tubes
• Debris in waterbox blocking tubes
The temperature difference will increase at low flow.
Check refrigerant-leaving chilled water difference at design
flow.
Compressor Surge — Surge is a repeated loss and recovery of the compressors aerodynamic lift. This loss of lift is
characterized by a reversal of flow back through the compressor. During surge there will be an intermittent high pitched
whistle signifying the reversal of the flow through the compressor. The pressure gages and the motor amps will rise and
fall.
Intermittent operation in surge is not normally detrimental
to the machine. Prolonged operation in surge can cause damage
related to heat build-up.
The ability of a centrifugal compressor to produce pressure
is directly related to the amount of gas passing through it, and
the lift characteristics on the compressor at these load points.
All of the possible causes are related to this fact. Computer
modeling of the 17DA compressor for each application can
provide guidance on how to adjust the characteristics of the operation to minimize the occurrence of surge.
The amount of required condenser water temperature reduction versus load reduction varies widely among centrifugal
compressors based on design and duty. The 17DA chiller is
able to handle deep load reductions without a major drop in
condenser water temperature. This does not imply that condenser water temperature should be held near design temperature at all times. It is an advantage to power consumption to
keep the condenser water temperature as low as possible down
to a minimum temperature. The minimum and maximum temperatures vary with machine and duty. They may be obtained
through your Carrier Service Office.
The following sections are some of the causes of surge and
corrections associated with them.
INSUFFICIENT LOAD TO MAINTAIN STABILITY —
Increase load on the machine. Open the optional hot gas
bypass. Reduce condenser water temperature. If none of these
20
Table 6A — HFC-134a Pressure —
Temperature (F)
TEMPERATURE,
F
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96
98
100
102
104
106
108
110
112
114
116
118
120
122
124
126
128
130
132
134
136
138
140
Table 6B — HFC-134a Pressure —
Temperature (C)
PRESSURE
(psig)
6.50
7.52
8.60
9.66
10.79
11.96
13.17
14.42
15.72
17.06
18.45
19.88
21.37
22.90
24.48
26.11
27.80
29.53
31.32
33.17
35.08
37.04
39.06
41.14
43.28
45.48
47.74
50.07
52.47
54.93
57.46
60.06
62.73
65.47
68.29
71.18
74.14
77.18
80.30
83.49
86.17
90.13
93.57
97.09
100.70
104.40
108.18
112.06
116.02
120.08
124.23
128.47
132.81
137.25
141.79
146.43
151.17
156.01
160.96
166.01
171.17
176.45
181.83
187.32
192.93
198.66
204.50
210.47
216.55
222.76
229.09
TEMPERATURE,
C
–18.0
–16.7
–15.6
–14.4
–13.3
–12.2
–11.1
–10.0
–8.9
–7.8
–6.7
–5.6
–4.4
–3.3
–2.2
–1.1
0.0
1.1
2.2
3.3
4.4
5.0
5.6
6.1
6.7
7.2
7.8
8.3
8.9
9.4
10.0
11.1
12.2
13.3
14.4
15.6
16.7
17.8
18.9
20.0
21.1
22.2
23.3
24.4
25.6
26.7
27.8
28.9
30.0
31.1
32.2
33.3
34.4
35.6
36.7
37.8
38.9
40.0
41.1
42.2
43.3
44.4
45.6
46.7
47.8
48.9
50.0
51.1
52.2
53.3
54.4
55.6
56.7
57.8
58.9
60.0
21
PRESSURE
(kPa)
44.8
51.9
59.3
66.6
74.4
82.5
90.8
99.4
108.0
118.0
127.0
137.0
147.0
158.0
169.0
180.0
192.0
204.0
216.0
229.0
242.0
248.0
255.0
261.0
269.0
276.0
284.0
290.0
298.0
305.0
314.0
329.0
345.0
362.0
379.0
396.0
414.0
433.0
451.0
471.0
491.0
511.0
532.0
554.0
576.0
598.0
621.0
645.0
669.0
694.0
720.0
746.0
773.0
800.0
828.0
857.0
886.0
916.0
946.0
978.0
1010.0
1042.0
1076.0
1110.0
1145.0
1180.0
1217.0
1254.0
1292.0
1330.0
1370.0
1410.0
1451.0
1493.0
1536.0
1580.0
temperature at the subcooler inlet thermowell. This is located
adjacent to the level control/transmitter.
If air is suspected, then check the purge. See the Purge Cycle section on page 19.
FOULED CONDENSER TUBES — Check for fouled or obstructed tubes. Clean as required.
Chilled Water Temperature Too Low with
Compressor Running
CHILLED WATER SET POINT IN THE PLC SET TOO
LOW — Correct set point and check for overrides from the
building control system.
LOW COOLING LOAD — The compressor cannot unload
completely. If there is so little load that the guide vanes close
fully, then the water temperature will continue to drop until the
recycle function or chilled water low-temperature safety stops
the machine.
INACCURATE THERMISTOR — The reading on the panel will not coincide with other sensors monitoring the leaving
chilled water.
SENSORS OUTSIDE OF THE CHILLER CONTROLS
ARE INACCURATE — The machine sensor could be correct
and other sensor(s) are out of calibration.
GUIDE VANES NOT CLOSING
• Check pressure of supply air and cushion air pressure.
• Confirm that the air signal from the transducer matches the
signal output from the PLC.
• Calibrate the positioner.
• Test the actuator for leakage past the piston seal.
Oil Pressure Too Low
PLUGGED FILTERS — Switch to alternate filter cartridge.
Replace plugged filter.
PRESSURE REGULATOR SET TOO LOW — Adjust as
required.
FAULTY PRESSURE REGULATOR — Replace regulator.
FAULTY PUMP OR MOTOR — Replace faulty component.
Oil Pressure Too High
PRESSURE REGULATOR SET TOO HIGH — Adjust as
required.
RESTRICTION IN PRESSURE SENSING LINE —
Check pressures and temperatures throughout lubrication system. Correct as required.
Oil Reservoir Temperature Too Low
Refrigerant Temperature Too Low
EXCESSIVE WATER FLOWING THROUGH OIL
COOLER
• Adjust water flow.
• If equipped with an automatic regulator, adjust the
regulator.
• Check for good thermal contact between the regulator sensing bulb and the oil line leaving the oil cooler. Check the
capillary tube for damage.
• Replace the regulator if faulty.
COOLER WATERBOX DIVISION PLATE GASKET OUT
OF PLACE — Fix gasket.
LOW REFRIGERANT CHARGE — When the machine can
be stopped, allow time for liquid to flow to the cooler. Compare
the liquid level with the charging mark on the cooler level
sightglass. Add refrigerant if required.
Check for leaks and check shutdown seal operation. Test refrigerant alarm sensors.
Oil Reservoir Temperature Too High
Leaving Chilled Water Temperature Fluctuates
INSUFFICIENT WATER FLOW THROUGH OIL
COOLER
• Adjust water flow.
• If equipped with an automatic regulator, then adjust the
regulator.
• Check for good thermal contact between the regulator sensing bulb and the oil line leaving the oil cooler. Check the
capillary tube for damage. Check for contamination plugging the regulator valve.
• Replace the regulator if faulty.
FOULED OR OBSTRUCTED
OIL
COOLER
TUBES — Check oil cooler. Clean if necessary.
TEMPERATURE OF OIL RETURNING FROM BEARINGS TOO HIGH — Check for bearing wear, in particular
the thrust bearing. Check the bearings for foreign particles or
any indication of wiping.
A bad bearing can cause extensive damage to machine. Be
sure to diagnose and correct reasons for overheated bearings
before restarting the machine.
RETURN CHILLED WATER TEMPERATURE FLUCTUATING FASTER THAN CONTROLS CAN RESPOND —
Adjust controls.
CAPACITY CONTROL IN PLC NEEDS ADJUSTING — Adjust capacity controls.
GUIDE VANES MOVING ERRATICALLY
• Check actuator (see Guide Vanes Not Closing section
above)
• With machine not running, disconnect the actuator and
move the guide vanes manually. There should be a resistance, easily overcome, at the point where the discharge diffuser starts opening or closing. Check for obstructions.
Condenser Pressure Too High
LOW WATER FLOW OR HIGH WATER TEMPERATURE — Check the following:
• Check condensing water pump for proper operation.
• Check delta P and delta T across the condenser water side to
determine if there is bypassing around the division plate.
• Check delta P across the condenser water pump.
• Check cooling tower controls and fans. Check to see if
tower bypass is open.
• Check for correct level in the cooling tower.
• Check flow meter readings.
• If the condenser water valves automatically regulate condenser flow, check the control settings and valve operation.
• Ensure that condenser water strainers are clean.
AIR IN THE CONDENSER — Air or other non-condensable gases in the condenser will cause a rise in normal condensing pressures. Because of the subcooler, true condensing temperatures cannot be determined. If the subcooler level is set according to the method in the Charge Refrigerant section, then
the actual condensing temperature will be close to the
Compressor Discharge Gas Temperature Too
High
EXTREMELY LOW LOAD — Verify low load condition.
Add load to machine if possible.
LOW COOLER REFRIGERANT LEVEL — Insufficient
charge in the machine or condenser refrigerant level too high.
EXCESSIVE TRAVEL OF DIFFUSER THROTTLING
RING — This can only be determined through compressor
disassembly.
CONTROLS
Safety Controls — Safety controls come in multiple
forms. Safety functions are programmed into the PLC which
22
positioner. A solenoid valve in the instrument line prevents the
actuator from opening the guide vanes until the start-up sequence is complete. The solenoid will also cause the guide
vanes to close immediately upon machine shut down. This prevents the pressure equalization gas flow from the condenser to
the cooler from back spinning the compressor and driver.
In case of supply air failure, the reserve air tank has sufficient volume to close the vanes.
The hot gas bypass valve works together with the guide
vanes. At low loads, the guide vane opening will be small. The
hot gas valve will start to open as the guide vanes approach the
minimum opening. The purpose of the hot gas bypass is to provide enough gas flow to the compressor to allow it to operate in
a stable way at low chiller loads.
The guide vane position as determined by water temperature can be overridden by other functions. Functions can override only to close the vanes and reduce the machines capacity.
No override can increase the guide vane position.
Override functions are:
• refrigerant temperature too low
• condenser pressure too high
• motor current too high, based on the demand limit set point.
Inside the compressor, the guide vane actuator shaft also
moves a diffuser throttle ring. Its position is determined by
cams. During low loads, typically below 50%, the guide vanes
and throttle ring move together. The diffuser throttling ring provides optimum performance down to 10% load. At higher
loads the throttle ring is fully open and capacity is controlled by
the guide vanes alone or in conjunction with variable compressor speed.
Variable frequency drives (VFDs) can be used along with
the guide vanes to control machine capacity. When a variable
speed drive or turbine is used, refer to the custom operating
manual for specific details of the control sequence.
Figure 12 shows a typical turbine control which determines
the required compressor speed using the difference between
leaving chilled water and entering condenser water. This is not
the only way to determine speed and sometimes the speed and
guide vane position are varied together to optimize power consumption. As long as the compressor speed required to maintain the desired leaving chilled water temperature is sufficient
to maintain the required condenser pressure, it is most economical to control capacity by varying speed alone. If higher compressor rpm is required to maintain condenser pressure, the
guide vanes will temporarily take control of capacity. The sequence is chosen based on individual job requirements.
Condenser refrigerant level is set when the machine is commissioned. The level ensures that the subcooler tubes are covered with liquid and the liquid level does not reach the condenser tubes. A level control on the condenser operates the
control valve in the line connecting the condenser drain with
the cooler liquid inlet.
The level control function can reside in the PLC. In that
case a level transmitter is mounted on the condenser in place of
a level controller. The control still operates the liquid line
valve.
use the same sensors as the operating functions. Per customer
specifications, these may be supplemented by mechanical
switches which directly measure pressures or temperatures.
These switches are connected to discrete inputs of the PLC and
the PLC controls the machine.
Starters and VFDs contain their own safeties that will shut
down the starter/drive and then report the trip to the PLC via
the communications line. It may be necessary to go to the drive
control panel to read the actual trip code. On the PLC, the display may only show that the trip was initiated by the drive.
STANDARD SAFETY FUNCTIONS — The following
safety functions are standard:
• low chilled water flow
• low condenser water flow
• high discharge gas temperature
• chilled water low temperature
• condenser high pressure
• cooler low pressure
• seal oil pressure
• bearing oil pressure
• thrust bearing high temperature
• seal movement switch
• excess shaft movement switch
• gear and turbine oil pressure switches
JOB SPECIFIC SAFETY FUNCTIONS — The settings for
job specific safety functions will be found in the custom operating manuals provided with the machine. Examples of job
specific safety functions are:
• vibration monitoring
• optional RTD bearing temperature sensors for the compressor and the drive components
• turbine overspeed
• failure of a synchronous motor to synchronize
• TEWAC (totally enclosed, water cooled) motor cooling coil
leak
Operating Controls — Figures 10 and 11 are schematic
representations of the basic control system governing water
temperature, power demand limit, and condenser liquid level
(liquid flow control). A comprehensive description of the complete control logic specific to each machine is provided in the
custom operating manual. A brief description of the basic schematic follows.
The primary control devices are the compressor guide
vanes, the hot gas bypass valve (optional) and the condensed
liquid valve. Compressor speed may also be varied on some
jobs. That will not be covered here.
Compressor inlet guide vanes control the amount of refrigerant gas that the compressor pulls from the cooler. By varying
this capacity, the control system maintains correct leaving water temperature. The correct temperature is set on the PLC and
can be also be set remotely. The PLC directs the position of the
guide vanes based on the leaving water temperature. The guide
vanes can also be controlled manually from the PLC.
The guide vane position signal is sent to an actuator that
moves the guide vanes in proportion to the control signal. The
standard actuator is pneumatic and the signal from the PLC is
converted to a 3 to 15 psi instrument signal to the actuator
23
PLC — Programmable Logic Controller
Fig. 10 — Typical 17DA Motor-Driven Machine Control Diagram
a17-579
24
25
PLC — Programmable Logic Controller
Fig. 11 — Typical 17DA Turbine-Driven Machine Control Diagram
FRONT VIEW
REAR VIEW
Fig. 12 — Machine Configuration
26
COMPRESSOR REAR VIEW
COMPRESSOR FRONT VIEW
LEGEND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
Free Cooling Vapor Valve (optional)
Sub-Cooler Refrigerant Level Controller
Cooler Sight Glass
Hot Gas Bypass Valve (optional)
Compressor Auxiliary Oil Pump
Purge Vapor Connection
Cooler Entering Water Temperature Instrument
Cooler Entering Water Flow Instrument
Cooler Leaving Water Temperature Instrument
Condenser Entering Water Temperature Instrument
Condenser Entering Water Flow Instrument
Condenser Leaving Water Temperature Instrument
Refrigerant Level Control Valve
Free Cooling Liquid Valve (optional)
Relief Valve
Purge
Condenser Refrigerant Liquid Temperature Instrument
Sub-Cooler Refrigerant Liquid Temperature Instrument
Discharge Temperature Instrument Connection
Cooler Refrigerant Liquid Temperature Instrument
Guide Vane Actuator
Positioner
Solenoid Valve
High Discharge Temperature Switch
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Thrust Bearing Temperature Instrument
Oil Filter
Oil Cooler
Oil Reservoir
Oil Reservoir Level Sightglass
Oil Reservoir Vent
Bearing Housing Vent
Compressor Seal End Journal Bearing RTD
Compressor Thrust End Journal Bearing RTD
Thrust Bearing Oil Return RTD
Oil Supply RTD
Bearing Supply Oil Pressure Transmitter
Oil Pump and Motor
OIl Differential Pressure Regulator Valve
Oil Pressure Regulator Valve
Shut Down Seal Solenoid Valve
Seal Supply Oil Pressure Transmitter
Seal Oil Return Pressure Transmitter
Thrust End Journal Bearing Transducer (X)
Thrust End Journal Bearing Transducer (Y)
Thrust End Bearing Transducer
Seal End Journal Bearing Transducer (X)
Seal End Journal Bearing Transducer (Y)
Fig. 12 — Machine Configuration (cont)
27
Copyright 2009 Carrier Corporation
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53170002-01
Printed in U.S.A.
Form 17DA-3SS
Pg 28
3-09
Replaces: 17DA-2SS,
17DA-3SO
1. Steam System
a. Is steam available? ______
b. Have the steam lines been blown out and checked for cleanliness? ______
c. Have the turbine steam inlet and exhaust chambers been checked for foreign material before steam lines are attached? ______
d. Are there adequate pipe hangers and supports on the steam lines and has an analysis of the piping been concluded to eliminate
piping stress on the turbine? ______
e. Have limiting rods been placed on expansion joints when they are used? ______
f. If a trip and throttle valve is supplied, does it have adequate support under it so that no weight or stress is placed
on the turbine? ______
g. Have all steam leak-off lines and drains been piped as indicated on the Dresser-Rand Outline drawing? ______
h. Has an atmospheric relief valve been installed in the exhaust line between the turbine and the first block valve? ______
2. Turbine Preparation
a. Has the turbine been rough aligned to the driven machine and grouted in? ______
b. Have all shipping plugs and/or blind flanges been removed from the oil pipes and lube console and oil lines cleaned
prior to installing? ______
c. Has oil tank been cleaned and inspected in preparation to filling with oil? ______
d. When oil console is supplied by others, has provisions been made to circulate oil and checked for cleanliness without
passing oil through the turbine? ______
e. Is piping complete and water available for oil cooler? ______
f. Has proper oil for turbine and driven machine been obtained and brought to jobsite? ______
g. Has auxiliary oil pump, where supplied, been checked for correct rotation? ______
h. Are pneumatic and electrical connections to the turbine governor and safety devices completed? ______
i. Is piping and wiring to gauge board, where furnished, complete? ______
3. Condensing Turbines Only
a. Has a means been provided to drain the casing while under vacuum? ______
b. Have the condenser condensate pumps been checked for correct rotation? ______
c. Has the condenser hot well level control been checked for correct operation? ______
Signed By: ____________________________________ Date: ____________
Firm Name: ______________________________________________________
Copyright 2009 Carrier Corporation
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53170002-01
Printed in U.S.A.
Form 17DA-3SS
Pg CL-1
3-09
Replaces: 17DA-2SS,
17DA-3SO
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - CUT ALONG DOTTED LINE
CUT ALONG DOTTED LINE
PRE-START UP CHECK LIST