Carrier 16DF013-050 User Manual
Hermetic Absorption Liquid Chillers/Heaters
Start-Up, Operation, and
Maintenance Instructions
SAFETY CONSIDERATIONS
Absorption liquid chillers/heaters 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 machine instructions as well as those
listed in this guide.
DO NOT USE OXYGEN or air to purge lines, leak test, or pressurize
a machine. Use nitrogen.
NEVER EXCEED specifie d test pressures. For the 16DF machine,
the maximum pressure is 12 psig (83 kPa). For the chilled/hot water
and condensing water piping, the maximum pressure is stamped on
the machine.
WEAR goggles and suitable protective clothing when handling lithium bromide, octyl alcohol, inhibitor, lithium hydroxide, and hydrobromic acid. IMMEDIATELY wash any spills from the skin with
soap and water. IMMEDIATELY FLUSH EYES with water and consult a physician.
DO NOT USE eyebolts or eyebolt holes to rig machine sections or the
entire assembl y.
DO NOT work on high-voltage equipment unless you are a qualified
electrician.
DO NOT WORK ON electrical components, including control panels or switches, 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.
NEVER DISCONNECT safety devices or bypass electric interlocks
and operate the machine. Also, never operate the machine when any
safety devices are not adjusted and functioning normally .
DO NOT REPEAT unsuccessful ignition attempts or restart after
flame failure without assurance that post-purge and prepurge have
eliminated combustible gas or all vapors from the combustion chamber. DO NOT EVER ATTEMPT IGNITION of a burner if there is
shutdown leakage of gas or oil through the fuel shutoff valves or from
the fuel lines.
DO NOT syphon lithium bromide or any other chemical by mouth.
BE SURE all hydrogen has been exhausted before cutting into purge
chambers. Hydrogen mixed with air can explode when ignited.
WHEN FLAMECUTTING OR WELDING on an absorption machine, some noxious fumes may be produced. Ventilate the area thoroughly to avoid breathing concentrated fumes.
DO NOT perform any welding or flamecutting to a machine while it
is under a vacuum or pressurized condition.
NEVER APPLY an open flame or live steam to a refrigerant cylinder. Dangerous overpressure can result. When necessary to heat a
cylinder, use only warm (1 10 F [43 C]) water.
DO NOT REUSE disposable (nonreturnable) cylinders or attempt to
refill them. It is DANG EROUS AND ILLEGAL. When c ylinder is
emptied, bleed off remaining gas pressure, loosen the collar and
unscrew and discard the valve stem. DO NOT INCINERATE.
DO NOT ATTEMPT TO REMOVE fittings, covers, etc., while machine is under pressure or while machine is running, and DO NOT
16DF013-050
OPERATE or pressurize a machine without all cover plates or bolts in
place.
→
CONNECT THE ABSORPTION CHILLER to a n em ergency power
source to ensure that a constant power supply is maintained to the unit
in the event that the main electrical power source is interrupted or
temporarily lost. Failure to provide an emergency power source to the
chiller could result in crystallization of the lithium bromide solution
inside the machine, rendering it temporarily inoperative. A potentially
lengthy decrystallization process might be required to return the
chiller to normal operation depending on the severity of the crystallization and/or the length of time the machine was without power.
→
PROVIDE AN EMERGENCY POWER SOURCE to the chilled
water and condenser water pumps to prevent the possibility of an
evaporator freeze-up. Failure to provide emergency power to these
pumps could result in machine operation with no flow of water
through the tubeside of the evaporator, absorber and condenser sections thereby allowing the water inside the evaporator tubes to freeze.
Further, a frozen evaporator tube can burst causing contamination of
the lithium bromide solution and the inside of the chiller. A freeze-up
in the evaporator will also result in a long period of chiller down time
due to the extensive repairs required to bring the chiller and the lithium bromide solution back to its original condition.
DO NOT climb over a machine. Use platform, catwalk, or staging.
Follow safe practices when using ladders.
DO NOT STEP ON machine piping. It might break or bend and cause
personal injury.
USE MECHANICAL EQUIPMENT (crane, hoist, etc.) to lift or
move inspection covers or other heavy components. Even if components are light, use such equipment when there is a risk of slipping
or losing your balance.
VALVE OFF AND TAG steam, water, or brine lines before opening
them.
DO NOT LOOSEN water box cover bolts until the water box has
been completely drained.
DO NOT VENT OR DRAIN water boxes containing industrial
brines, liquid, gases, or semisolids without permission of your process
control group.
BE AWARE that certain automatic start arrangements can engage
starters. Open the disconnect s a head of th e st ar ters i n addition to shutting off the machine or pum p.
INVESTIGATE THE CAUSE of flame failure or any other safety
shutdown before attempting a restart.
KEEP EYES sufficiently away from sight tubes or burner openings,
and wear a protective shield or safety glasses when viewing a burner
flame.
USE only replacement parts that meet the code requirements of the
original equipment.
DO NOT ALLOW UNAUTHORIZED PERSONS to tamper with
burner equipment or machine safeties, or to make major repairs.
PERIODICALLY INSPECT all valves, fittings, piping, and relief
devices 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.
IMMEDIATELY wipe or flush the floor if lithium bromide or octyl
alcohol is spilled on it.
BE SURE combustion air inlets to the equipment room are open and
clear of any blockage.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
Ta b 5 b
PC 211 Catalog No. 531-603 Printed in U.S.A. Form 16DF-1SS Pg 1 801 5-92 Replaces: New
CONTENTS
Page
INTRODUCTION ..............................3
MACHINE DESCRIPTION ...................3-13
Basic Absorption Cooling Cycle ..............3
Double Effect Reconcentration ................3
Basic Heating Cycle ..........................3
Machine Construction ........................3
Cooling Cycle Flow Circuits ..................6
Heating Cycle Flow Circuits ..................6
Solution Cycle and Equilibrium Diagram ......9
• PLOTTING THE COOLING SOLUTION CYCLE
• PLOTTING THE HEATING SOLUTION CYCLE
Purge ......................................13
Operation Status Indicators ..................13
Burner .....................................13
MACHINE CONTROLS .....................14-32
General .....................................14
Start-Stop System ...........................14
• SEMIAUTOMATIC START-STOP
• FULL AUTOMATIC START-STOP
Machine Control Panel ......................14
Status Indicator Sticker .....................15
Adjustment Switches ........................15
• TOGGLE SWITCHES
• SET POINT AND DIP SWITCHES
Indicator LEDs ..............................16
Remaining Time Indication for
Dilution Cycle .............................19
Control Wiring ..............................19
Typical Control Sequence —
Normal Cooling Start ......................25
Typical Control Sequence —
Normal Heating Start ......................25
Typical Control Sequence —
Normal Cooling Stop ......................28
Typical Control Sequence —
Normal Heating Stop ......................28
Abnormal Shutdown ........................29
Operating Limit Controls ....................30
• HIGH-TEMPERATURE GENERATOR,
HIGH SOLUTION LEVEL
• HIGH-TEMPERATURE GENERATOR,
HIGH LEAVING SOLUTION TEMPERATURE
• HIGH-TEMPERATURE GENERATOR,
HIGH-SATURATION (VAPOR) TEMPERATURE
• CONCENTRATION CONTROL VALVE
• COOLING TOWER CONTROL
Automatic Capacity Control .................31
• TEMPERATURE CONTROL SETTINGS
• CHILLED/HOT WATER TEMPERATURE
DISPLAY
Burner Control ..............................32
• COMBUSTION CONTROL
• FIRING RATE CONTROL
BEFORE INITIAL START-UP ................32-36
Job Data and Tools Required ................32
Inspect Field Piping .........................33
Inspect Field Wiring .........................33
Inspect Machine Controls ...................34
• PREPARATION
• CHECK COOLING CYCLE START
• CHECK HERMETIC PUMP STARTERS
AND SHUTDOWN CYCLE
• CHECK HERMETIC PUMP MOTOR OVERLOADS
• CHECK BURNER INTERLOCKS
• CHECK LOW CHILLED WATER
TEMPERATURE CUTOUT
• CHECK HEATING CYCLE START AND STOP
• CHECK WATER FLOW SWITCHES
Page
• CHECK HIGH-STAGE GENERATOR
LOW SOLUTION LEVEL SWITCH
• CHECK HIGH COMBUSTION TEMPERATURE
SWITCHES
• CHECK HIGH-STAGE GENERATOR
TEMPERATURE SWITCH
• CHECK HIGH-STAGE GENERATOR
PRESSURE SWITCH
• RESTORATION
Burner System ..............................36
• GENERAL
• GAS FIRING
• OIL FIRING
Standing Vacuum Test ......................36
• LONG INTERVAL TEST
• SHORT INTERVAL TEST
Machine Evacuation .........................36
INITIAL START-UP .........................37-40
Job Data and Tools Required ................37
Noncondensable Evacuation .................37
Solution and Refrigerant Charging ...........37
• HANDLING LITHIUM BROMIDE SOLUTION
• CHARGING SOLUTION
• INITIAL REFRIGERANT CHARGING
Operational Controls Check and
Adjustment ...............................39
• PREPARATION
• WATER PUMP STARTERS
AND OVERLOADS
• HERMETIC PUMP ROTATION
Initial Combustion ..........................39
Add Octyl Alcohol ...........................40
Initial Start Operation .......................40
Capacity Control Adjustments ...............40
Refrigerant Charge Final Adjustment .........40
Check Machine Shutdown ...................40
OPERATING INSTRUCTIONS ...............40-45
Operator Duties .............................40
Before Starting Machine .....................43
Cooling/Heating Operation
Changeover ..............................43
• CHANGING FROM COOLING CYCLE
TO HEATING CYCLE
• CHANGING FROM HEATING CYCLE
TO COOLING CYCLE
Start Machine ...............................43
Heating Start-Up or Cooling Start-Up
After Limited Shutdown ...................43
Cooling Start-Up After
Extended Shutdown (More than 21 Days) ...43
Start-Up After Below-Freezing
Conditions ................................43
Operation Check ............................43
Normal Shutdown Procedure ................44
Shutdown Below Freezing Conditions ........45
Actions After Abnormal Shutdown ...........45
Actions After Power Interruption .............45
PERIODIC SCHEDULED MAINTENANCE ......46
Every Day of Operation ......................46
Every Month of Operation ...................46
Every 2 Months of Operation ................46
Every 6 Months of Operation or
Cooling/Heating Changeover ..............46
Every Year (At Changeover of Cooling/
Heating Cycle or Shutdown) ...............46
Every 2 Years ...............................46
Every 5 Years or 20,000 Hours
(Whichever is Shorter) ....................46
2
CONTENTS (cont)
Page
MAINTENANCE PROCEDURES .............46-53
Log Sheets .................................46
Absorber Loss Determination ................46
Machine Leak Test ..........................46
Machine Evacuation .........................48
Purge Exhaust Procedure ...................48
Solution or Refrigerant Sampling ............48
• SOLUTION SAMPLE
• REFRIGERANT SAMPLE
Solution Analysis ...........................49
Inhibitor ....................................49
Adding Octyl Alcohol ........................49
Removing Lithium Bromide from Refrigerant .49
Refrigerant Charge Adjustment ..............49
Page
Capacity Control Adjustment ................49
Operating and Limit Controls ................49
Burner Checks and Adjustments .............50
Service Valve Diaphragm Replacement .......50
Hermetic Pump Inspection ...................50
• DISASSEMBLY
• INSPECTION
• REASSEMBLY
• COMPLETION
Condensing Water Tube Scale ...............53
Water Treatment ............................53
Solution Decrystallization ...................53
Internal Service .............................53
TROUBLESHOOTING GUIDE ...............54-56
INTRODUCTION
Everyone involved in the start-up, operation, and maintenance of the 16DF machine should be thoroughly familiar
with these instructions, the separate burner instructions, and
other necessary job data before initial start-up, and before
operating the machine or performing machine maintenance.
Procedures are arranged in the sequence required for proper
machine start-up and operation.
NOTE: In this manual, temperatures are shown in °C first,
with °F given in parentheses ( ), when a temperature display is in °C or a control set point scale is in °C values.
MACHINE DESCRIPTION
Basic Absorption Cooling Cycle —
sorption chiller uses water as the refrigerant in vessels maintained under a deep vacuum. The chiller operates on the simple
principle that under low absolute pressure (vacuum), water
takes up heat and vaporizes (boils) at a low temperature. For
example, at the very deep vacuum of 0.25 in. (6.4 mm) of
mercury absolute pressure, water boils at the relatively cool
temperature of only 40 F (4 C). To obtain the energy required for this boiling, it takes heat from, and therefore chills,
another fluid (usually water). The chilled fluid then can be
used for cooling purposes.
To make the cooling process continuous, the refrigerant
vapor must be removed as it is produced. For this, a solution
of lithium bromide salt in water is used to absorb the water
vapor. Lithium bromide has a high affinity for water, and
will absorb it in large quantities under the right conditions.
The removal of the refrigerant vapor by absorption keeps
the machine pressure low enough for the cooling vaporization to continue. However, this process dilutes the solution
and reduces its absorption capacity. Therefore, the diluted
lithium bromide solution is pumped to separate vessels where
it is heated to release (boil off) the previously absorbed water. Relatively cool condensing water from a cooling tower
or other source removes enough heat from this vapor to condense it again into liquid for reuse in the cooling cycle. The
reconcentrated lithium bromide solution is returned to the
original vessel to continue the absorption process.
The 16DF ab-
Double Effect Reconcentration — With this chiller,
reconcentration of the solution is done in 2 stages to improve the operating efficiency. Approximately half of the
diluted solution is pumped to a high-temperature vessel (high
stage) where it is heated for reconcentration directly from
the combustion of gas or light oil. The rest of the solution is
pumped to a low-temperature vessel (low stage) where it is
heated by the hotwatervaporgeneratedinthehigh-temperature
vessel. The low stage acts as the condenser for the high stage,
so the heat energy first applied in the high-stage vessel is
used again in the low-stage vessel. This cuts the heat input
to almost half of that required for an absorption chiller with
a single-stage reconcentrator.
Basic Heating Cycle — The heating cycle uses a dif-
ferent vapor flow path than that used for cooling, and does
not use the absorption process. The high-temperature water
vapor produced in the direct fired high-stage vessel is passed
directly to the heating tubes where it condenses and transfers its heat into the circulating hot water. The condensed
water then flows by gravity to mix with the concentrated solution which had returned from the high-stage vessel. This
diluted solution then is pumped back to the high-stage vessel to repeat the vapor generation for the heating function.
Machine Construction — The major sections of
the machine are contained in several vessels (Fig. 1- 4,
Table 1).
The large lower shell contains the evaporator section in
its upper part and the absorber section at the bottom. In the
evaporator,therefrigerantwatervaporizesinthe cooling cycle
and cools the chilled water for the air conditioning or cooling process. In the heating cycle, hot water vapor flows into
the evaporator section where it condenses and heats the hot
water for the heating process. The heat transfer tube bundle
in the evaporator is used for both cooling and heating. In the
absorber, vaporized refrigerant water is absorbed by lithium
bromide solution in the cooling cycle. In the heating cycle,
condensed refrigerant water from the evaporator drains into
the absorber where it is mixed with the strong solution.
The short vessel with the burner, located next to the
evaporator/absorber assembly,is the high-stage generator.The
vessel above it is the separator. In both the cooling and heating cycles, approximately half of the diluted lithium bromide solution is heated directly from the combustion of gas
or oil. The water vapor created in this process is released
from the reconcentrated solution in the separator vessel.
3
The smaller shell above the evaporator/absorber assembly contains the low-stage generator and condenser. In the
cooling cycle, about half of the diluted lithium bromide
solution is heated and reconcentrated in the low-stage
generator by high-temperature vapor from the high-stage generator. The water vapor released from the solution in this
process is condensed to liquid in the condenser section. This
vessel is not used in the heating cycle, although about half
of the diluted solution does flow through the generator.
This chiller also has: 2 solution heat exchangers to improve operating economy; an external purge system to maintain machine vacuum by the continuous removal of noncondensables; 2 hermetic pumps to circulate the solution and
refrigerant; various operation, capacity, and safety devices
to provide automatic, reliable machine performance; and the
ability to manually switch between cooling and heating
operation.
Fig. 1 — 16DF Machine, Front View
Fig. 2 — Machine Controls and Components, Schematic
4
Fig.3—Valve and Component Locations, Front View
Fig.4—Valve and Component Locations, Rear View
5
Table1—Valve Descriptions
VALV E US E
A Heating/Cooling Vapor
B Heating/Cooling Liquid
C Heat Exchanger Service
D Palladium Cell Isolation
E Purge Storage Tank Evacuation
F Auxiliary Evacuation
G Vacuum/Pressure Gage
H Solution Pump Service
J Refrigerant Pump Service
K High-Stage Generator Service
Cooling Cycle Flow Circuits — Figure 5 illustrates
the basic flow circuits of the 16DF absorption chiller during
the cooling cycle.
The liquid to be chilled is passed through the evaporator
tube bundle and is cooled by the evaporation of refrigerant
water sprayed over the outer surface of the tubes by the recirculating refrigerant pump. The refrigerant vapors are drawn
into the absorber section and are absorbed by the lithium
bromide-water solution sprayed over the absorber tubes. The
heat picked up from the chilled liquid is transferred from the
absorbed vapor to cooling water flowing through the absorber tubes.
The solution in the absorber becomes diluted as it absorbs
water, and loses its ability to continue the absorption. It is
then transferred by the solution pump to the generator sections to be reconcentrated. Approximately half of the weak
(diluted) solution goes to the high-stage generator where it
is heated directly by the combustion of gas or oil to boil out
the absorbed water. The mixture of reconcentrated solution
and vapor rises to the separator, where the vapor is released
and is then passed to the low-stage generator tubes. In the
low-stage generator, the rest of the weak solution is heated
by the high-temperature vapor from the high-stage separator, to boil out the remaining absorbed water.
The resulting water vapor from the low-stage generator
solution passes into the condenser section and condenses on
tubes containing cooling water.This is the same cooling water which had just flowed through the absorber tubes. The
condensed high-temperature water from the low-stage generator tubes is also passed over the condenser tubes where it
is cooled to the condenser temperature. The combined condensed refrigerant liquid, from the 2 generators, now flows
back to the evaporator to begin a new refrigerant cycle.
The strong (reconcentrated) solution flows from the 2 generators back to the absorber spray headers to begin a new
solution cycle. On the way, it passes through solution heat
exchangers where heat is transferred from the hot, strong solution to the cooler, weak solution being pumped to the generators. Solution to and from the high-stage generator passes
through both a high-temperature heat exchanger and a lowtemperature heat exchanger. Solution to and from the lowstage generator passes through only the low-temperature heat
exchanger,mixedwiththe high-stage generator solution. This
heat transfer improves solution cycle efficiency by preheating the relatively cool, weak solution before it enters the generators, and precooling the hotter, strong solution before it
enters the absorber.
During high-load cooling operation, some abnormal conditions can cause the lithium bromide concentration to increase above normal. When this happens, a small amount of
refrigerant is transferred by an evaporator overflow pipe into
the absorber solution to limit the concentration. This is necessary to keep the strong solution concentration away from
crystallization (see Solution Cycle and Equilibrium Diagram section, page 9).
The evaporator refrigerant level is directly related to machine solution concentration. As the concentration increases
(has less water), so does the refrigerant level. As the solution
concentration increases beyond a safe limit, the refrigerant
level rises to the level of the overflow pipe and some spills
over to flow into the absorber. The concentration at which
the refrigerant overflows is determined by the amount of refrigerant (water) which is charged into the machine.
If, for some reason, the machine controls and evaporator
overflow do not prevent strong solution crystallization during abnormal operating conditions, and flow blockage occurs, the strong solution overflow pipe will reverse or limit
the crystallization until the cause can be corrected. The overflow pipe is located between the low-temperature generator discharge box and the absorber, bypassing the heat
exchangers.
If crystallization occurs, it generally takes place in the shell
side of the low-temperature heat exchanger, blocking the flow
of strong solution from the generators. The strong solution
then backs up in the discharge box and spills over into the
overflow pipe, which returns it directly to the absorber sump.
The solution pump then returns this hot solution through the
heat exchanger tubes, automatically heating and decrystallizing the shell side.
Heating Cycle Flow Circuits — Figure 6 illustrates
the basic flow circuits of the 16DF absorption chiller during
the heating cycle.
The liquid to be heated is passed through the evaporator
tube bundle and is heated by condensation of hot water vapor from the high-stage generator. The solution flowing from
the absorber, through the heat exchangers to the generators
via the solution pump, and then back through the heat exchangers to the absorber sprays is basically the same as in
the cooling cycle. However, the solution is heated and reconcentrated only in the high-stage generator. The heating
refrigerant water cycle is quite different from that of the cooling cycle. The cooling water flow is turned off, as is the refrigerant recirculating pump.Thehigh-temperaturewatervapor
from the high-stage generator is diverted to the evaporator,
and the condensed vapor in the evaporator is drained directly to the absorber solution.
6
A,B — Connecting Piping from Purge
CA1 — Solution Pump Motor Overload
CA2 — Refrigerant Pump Motor Overload
CA3 — Burner Blower Motor Overload
FA1 — Chilled/Hot Water Flow Switch
FD — Burner Flame Detector
LCD — Level Control Device
M—Burner Firing Rate Positioning
PA1 — High-Temperature Generator High-
PA2 — Low Gas Pressure Switch
PA3 — High Gas Pressure Switch
PA4 — Low Combustion Air Pressure
*See Purge Unit insert.
NOTE: Service valve connections are
Unit Diagram to Machine Cycle
Diagram
Motor
Pressure Switch
Switch
1
⁄2-in. NPT.
LEGEND
PI1 — High-Temperature Generator
Pressure Gage
PI3 — Supply Gas Pressure Gage
PI4 — Regulated Gas Pressure Gage
TA1 — Chilled/Hot WaterTemperature Limit
TA2 — Solution Pump Motor High-
Temperature Limit
TA3 — Exhaust Gas High-Temperature
Limit
TA4 — Fire Tube High-Temperature Limit
TA5 — Return End Refractory
High-Temperature Limit
TI1-3 — Weak Solution Temperature
Measurement Wells
TI4-6 — Strong Solution Temperature
Measurement Wells
Fig. 5 — Cooling Cycle with Data Points
TI7 — Refrigerant Temperature
Measurement Well
TI8 — Refrigerant Condensate Tempera-
ture Measurement Well
TI9 — Exhaust Gas Temperature
Measurement Gage
TS1 — Leaving Chilled/Hot Water
Temperature Sensor
TS2 — Weak Solution Temperature
Sensor
TS3 — High-Temperature Generator
Vapor Temperature Sensor
TS4 — Entering Chilled/Hot Water
Temperature Sensor
TS5 — High-Temperature Generator
Strong Solution Temperature
Sensor
7
A,B — Connecting Piping from Purge
CA1 — Solution Pump Motor Overload
CA2 — Refrigerant Pump Motor Overload
CA3 — Burner Blower Motor Overload
FA1 — Chilled/Hot Water Flow Switch
FD — Burner Flame Detector
LCD — Level Control Device
M—Burner Firing Rate Positioning
PA1 — High-Temperature Generator High-
PA2 — Low Gas Pressure Switch
PA3 — High Gas Pressure Switch
PA4 — Low Combustion Air Pressure
*See Purge Unit insert.
NOTE: Service valve connections are
Unit Diagram to Machine Cycle
Diagram
Motor
Pressure Switch
Switch
1
⁄2-in. NPT.
LEGEND
PI1 — High-Temperature Generator
Pressure Gage
PI3 — Supply Gas Pressure Gage
PI4 — Regulated Gas Pressure Gage
TA1 — Chilled/Hot WaterTemperature Limit
TA2 — Solution Pump Motor High-
Temperature Limit
TA3 — Exhaust Gas High-Temperature
Limit
TA4 — Fire Tube High-Temperature Limit
TA5 — Return End Refractory
High-Temperature Limit
TI1-3 — Weak Solution Temperature
Measurement Wells
TI4-6 — Strong Solution Temperature
Measurement Wells
Fig. 6 — Heating Cycle with Data Points
TI7 — Refrigerant Temperature
Measurement Well
TI8 — Refrigerant Condensate Tempera-
ture Measurement Well
TI9 — Exhaust Gas Temperature
Measurement Gage
TS1 — Leaving Chilled/Hot Water
Temperature Sensor
TS2 — Weak Solution Temperature
Sensor
TS3 — High-Temperature Generator
Vapor Temperature Sensor
TS4 — Entering Chilled/Hot Water
Temperature Sensor
TS5 — High-Temperature Generator
Strong Solution Temperature
Sensor
8
Solution Cycle and Equilibrium Diagram — The
solution cycles for cooling and heating operation can be illustrated by plotting them on a basic equilibrium diagram
for lithium bromide in solution with water (Fig. 7 and 8).
The diagram is also used for performance analyses and
troubleshooting.
The left scale on the diagram indicates solution and water
vapor pressures at equilibrium conditions. The right scale
indicates the corresponding saturation (boiling or condensing) temperatures of the refrigerant (water).
The bottom scale represents solution concentration, expressed as percentage of lithium bromide by weight in solution with water. For example, a lithium bromide concentration of 60% means 60% lithium bromide and 40% water
by weight.
The curved lines running diagonally left to right are solution temperature lines (not to be confused with the horizontal saturation temperature lines). The single curved line
beginning at the lower right represents the crystallization line.
The solution becomes saturated at any combination of temperature and concentration to the right of this line, and it
will begin to crystallize (solidify) and restrict flow.
The slightly sloped lines extending from the bottom of the
diagram are solution-specific gravity lines. The concentration of a lithium bromide solution sample can be determined
by measuring its specific gravity with a hydrometer and reading its solution temperature. Then, plot the intersection point
for these 2 values and read straight down to the percent lithium
bromide scale. The corresponding vapor pressure can also
be determined by reading the scale straight to the left of the
point, and its saturation temperature can be read on the scale
to the right.
PLOTTING THE COOLING SOLUTION CYCLE — An
absorption solution cycle at typical full load conditions is
plotted in Fig. 7 from Points 1 through 12. The corresponding values for these typical points are listed in Table 2. Note
that these values will vary with different loads and operating
conditions.
Point 1 represents the strong solution in the absorber, as it
begins to absorb water vapor after being sprayed from the
absorber nozzles. This condition is internal and cannot be
measured.
Point 2 represents the diluted (weak) solution after it leaves
the absorber and before it enters the low-temperature heat
exchanger.Thisincludes its flow through the solution pump.
This point can be measured with a solution sample from the
pump discharge.
Point 3 represents the weak solution leaving the lowtemperature heat exchanger. It is at the same concentration
as Point 2 but at a higher temperature after gaining heat from
the strong solution. This temperature can be measured. At
this point, the weak solution is split, with approximately half
of it going to the low-stage generator,and the rest of it going
on to the high-temperature heat exchanger.
Point 4 represents the weak solution in the low-stage generator after being preheated to the boiling temperature. The
solution will boil at temperatures and concentrations corresponding to a saturation temperature established by the vapor condensing temperature in the condenser. This condition
is internal and cannot be measured.
Point 5 represents the weak solution leaving the hightemperature heat exchanger and entering the high-stage generator. It is at the same concentration as Points 2 and 3, but
at a higher temperature after gaining heat from the strong
solution. This temperature can be measured.
Point 6 represents the weak solution in the high-stage generator after being preheated to the boiling temperature. The
solution will boil at temperatures and concentrations corresponding to a saturation temperature established by the vapor condensing temperature in the low-stage generator tubes.
This condition is internal and cannot be measured.
Point 7 represents the strong solution leaving the high-stage
generator and entering the high-temperature heat exchanger
after being reconcentrated by boiling out refrigerant. It can
be plotted approximately by measuring the temperatures of
the leaving strong solution and the condensed vapor leaving
the low-stage generator tubes (saturation temperature). This
condition cannot be measured accurately.
Point 8 represents the strong solution from thehigh-temperature
heat exchanger as it flows between the 2 heat exchangers. It
is the same concentration as Point 7, but at a cooler temperature after giving up heat to the weak solution. It is an
internal condition and cannot be measured.
Point 9 represents the strong solution leaving the low-stage
generator and entering the low-temperature heat exchanger.
It is at a weaker concentration than the solution from the
high-stage generator, and can be plotted approximately by
measuring the temperatures of the leaving strong solution
and vapor condensate (saturation temperature). This condition cannot be measured accurately.
Point 10 represents the mixture of strong solution from the
high-temperature heat exchanger and strong solution from
the low-stage generator after they both enter the lowtemperature heat exchanger. It is an internal condition and
cannot be measured.
Point 11 represents the combined strong solution before it
leaves the low-temperature heat exchanger after giving up
heat to the weak solution. This condition is internal and cannot be measured.
Point 12 represents the strong solution leaving the lowtemperature heat exchanger and entering the absorber spray
nozzles, after being mixed with some weak solution in the
heat exchanger. The temperature can be measured but the
concentration cannot be sampled. After leaving the spray
nozzles, the solution is somewhat cooled and concentrated
as it flashes to the lower pressure of the absorber.
9
Fig. 7 — Equilibrium Diagram, Cooling Cycle
Table2—Typical Full Load Cooling Cycle Equilibrium Data
POINT
1 111 44 0.26 6.6 62.2 41 5
2 100 38 0.26 6.6 59.0 41 5
3 158 70 1.20 30.0 59.0 84 29
4 181 83 2.20 56.0 59.0 104 40
5 289 143 23.00 584.0 59.0 198 92
6 300 149 27.00 686.0 59.0 208 98
7 332 167 27.00 686.0 64.5 208 98
8 167 75 0.80 20.3 64.5 72 22
9 194 90 2.20 56.0 62.0 104 40
10 178 81 1.30 33.0 63.4 86 30
11 126 52 0.39 9.9 63.4 51 11
12 117 47 0.30 7.6 62.0 45 7
SOLUTION TEMPERATURE VAPOR PRESSURE
°F °C in. Hg mm Hg °F °C
SOLUTION PERCENTAGE
LITHIUM BROMIDE
SATURATION TEMPERATURE
10
PLOTTING THE HEATING SOLUTION CYCLE —Aheating solution cycle at typical full load conditions is plotted in
Fig. 8 from Points 1 through 11. The corresponding values
for these typical points are listed in Table3.Theheating cycle
operates with lower (more dilute) solution concentrations than
used with the cooling cycle because most of the refrigerant
water is drained from the evaporator into the solution. Note
that these values will vary with different loads and operating
conditions.
Point 1 represents the strong solution in the absorber after
being sprayed from the absorber nozzles, before it begins to
mix with condensed water vapor draining from the evaporator. The temperature of the solution to the spray nozzles
can be measured, but the concentration cannot be sampled.
Point 2 represents the diluted (weak) solution, with the condensed water, leaving the absorber and entering the lowtemperature heat exchanger.Thispoint can be measured with
a solution sample from the pump discharge.
Point 3 represents the weak solution as it leaves the lowtemperature heat exchanger. It is at the same concentration
as Point 2 but at a slightly warmer temperature after gaining
some heat from the strong solution. This temperature can be
measured. At this point, the weak solution is split, with approximately half of it going to the low-stage generator, and
the rest of it going to the high-temperature heat exchanger.
Although the solution sent to the low-stage generator is not
used in the heating function, the solution distribution and
flow rates are maintained approximately the same as in the
cooling cycle to minimize piping and control differences.
Point 4 represents the weak solution as it leaves the hightemperature heat exchanger and enters the high-stage generator. It is at the same concentration as Points 2 and 3, but
at a higher temperature after gaining heat from the strong
solution. This temperature can be measured.
Point 5 represents the weak solution in the high-stage generator after being preheated to the boiling temperature. The
solution will boil at temperatures and concentrations corresponding to a saturated temperature established by the vapor
condensing temperature in the evaporator. This condition is
internal and cannot be measured.
Point 6 represents the strong solution leaving the high-stage
generator and entering the high-temperature heat exchanger
after being reconcentrated by boiling out refrigerant water.
The heat energy in the vapor produced in this process is used
directly for heating the circulating hot water in the evaporator. The leaving strong solution temperature can be measured but the saturation temperature cannot be measured accurately to plot the point.
Point 7 represents the strong solution from thehigh-temperature
heat exchanger as it flows between the two heat exchangers.
It is the same concentration as Point 6, but at a cooler temperature after giving up heat to the weak solution. It is an
internal condition and cannot be measured.
Point 8 represents the weak solution leaving the low-stage
generator and entering the low-temperature heat exchanger.
It is at a slightly higher concentration than the entering solution because it has picked up some heat from the hot vapor
in the generator tubes, as an incidental occurrence in the flow
process.
Point 9 represents the mixture of strong solution from the
high-temperature heat exchanger and the weak solution from
the low-stage generator after they both enter the lowtemperature heat exchanger. It is an internal condition and
cannot be measured.
Point 10 represents the combined strong solution before it
leaves the low-temperature heat exchanger, after giving up
heat to the weak solution. This is an internal condition and
cannot be measured.
Point 11 represents the strong solution leaving the lowtemperature heat exchanger and entering the absorber spray
nozzles, after being mixed with some weak solution in the
heat exchanger. The temperature can be measured, but the
concentration cannot be sampled. After leaving the spray
nozzles, the solution is somewhat cooled and concentrated
as it flashes to the lower pressure of the absorber.
11
Fig. 8 — Equilibrium Diagram, Heating Cycle
Table3—Typical Full Load Heating Cycle Equilibrium Data
POINT
1 188 87 4.1 104 54.4 127 53
2 188 87 6.4 163 50.5 142 61
3 199 93 8.0 203 50.5 152 67
4 248 120 21.0 533 50.5 199 93
5 255 124 24.0 610 50.5 207 97
6 307 153 24.0 610 60.6 207 97
7 195 91 2.8 71 60.6 113 45
8 202 94 8.0 203 51.5 152 67
9 198 92 4.7 119 56.0 130 54
10 190 88 4.0 102 56.0 125 52
11 190 88 4.9 124 54.0 131 55
SOLUTION TEMPERATURE VAPOR PRESSURE
°F °C in. Hg mm Hg °F °C
SOLUTION PERCENTAGE
LITHIUM BROMIDE
SATURATION TEMPERATURE
12
Purge — The basic components and flow circuits of the
motorless purge are shown in Fig. 9.
The purge system automatically removes noncondensables from the machine and transfers them to a storage chamber where they cannot affect machine operation.
Noncondensables are gases which will not condense at the
normal chiller operating temperatures and pressures (N
, etc.) and, because they reduce the machine vacuum, they
H
2
would also reduce the machine capacity.
Hydrogen (H
normal operation, and its rate of generation is controlled by
) gas is liberated within the machine during
2
the solution inhibitor. The presence of most other gases in
the machine would occur either through a leak (the machine
is under a deep vacuum) or during service activities.
While the machine is operating, any noncondensables accumulate in the absorber which is the lowest pressure area
of the machine.
For purging, noncondensables are continuously drawn from
the absorber into the lower pressure of an eductor, where
they are entrained in solution flowing from the solution pump.
The mixture then continues on to the purge storage tank. The
noncondensables are released in a separator and the solution
flows back to the absorber by way of the generator overflow
pipe. Typicallymost of the noncondensable gas is hydrogen,
which is automatically passed out to the atmosphere through
a heated palladium membrane cell.
Any other gas accumulates in the purge storage tank where
it is isolated from the rest of the machine. It is then removed
from the storage tank, when necessary, by a vacuum pump
connected to the tank exhaust valve. If the machine is maintained in a leak-tight condition, as it should be, the storage
tank is normally exhausted once or twice a year, during a
normal shutdown period or seasonal changeover. When it is
necessary to remove noncondensables directly from the machine, such as after service work, a vacuum pump can be
connected to the auxiliary evacuation valve, which is connected directly to the absorber through an isolation check
valve.
2,O2
Operation Status Indicators — The 16DF absorp-
tion chiller/heater is equipped with several instruments and
sight glasses for direct observation of its operation in addition to a digital display of the temperature sensed for machine control and for codes (Tables 4 and 5).
,
DESCRIPTION LOCATION FUNCTION
High-Temperature
Generator Compound
Gage
Exhaust Gas
Thermometer
Table 4 — 16DF Instruments
Low-Temperature
Generator
Steam Chamber
High-Temperature
Generator
Exhaust Stack
High-Temperature
Generator
Vessel Pressure
Exhaust Gas
Discharge
Temperature
Table 5 — 16DF Sight Glass
DESCRIPTION LOCATION FUNCTION
Absorber Sight
Glass
High-Temperature
Generator
Sight Glass
Combustion
Chamber
Sight Glass
Evaporator Refrigerant
Overflow Pipe
High-Temperature
Generator Level
Control Device Box
High-Temperature
Generator
Combustion Chamber
Return End
Absorber
Liquid Level
Refrigerant Overflow
High-Temperature
Generator
Liquid Level
Combustion and
Refractory
Insulation
Status
Burner — The burner is a packaged, forced-draft type,
with modulating firing rate control. It is supplied with components selected for operation with either gas, light oil, or
both fuels, and with appropriate safety and control components to comply with specified code, insurance, and jurisdictional agency requirements.
Specific information is contained in the burner manual ac-
companying each burner.
Fig. 9 — Purge System
13
MACHINE CONTROLS
This machine uses a microprocessor control system. Do
not short or jumper between terminations on printed circuit boards. Control or board failure may result. Also,
when performing welding, wiring, or an insulation resistance test on the machine, disconnect wiring to the
CPU (Control Processing Unit) board to avoid risk of
voltage damage to the board components.
Be aware of electrostatic discharge (static electricity)
when handling or making contact with the printed circuit boards. Always touch a grounded chassis part to
dissipate body electrostatic charge before working inside the control center.
Use extreme care when handling tools near boards
and when connecting or disconnecting terminal plugs.
Circuit boards can easily be damaged. Always holdboards
by edges and avoid touching components and pin connections. Always store and transport replacement or defective boards in anti-static bags.
General — The 16DF machine uses a microprocessor-
based control center which monitors and controls all operations of the machine. It also has a separate burner control
center, under direction of the machine control center, to provide burner sequence control and combustion supervision.
The integrated control system matches the cooling and heating capacities of the machine to the respective cooling and
heating loads, while providing state-of-the-art machine
protection.
The system controls the machine output temperatures within
the set point deadband by sensing the leaving chilled and hot
water temperatures and regulating the burner heat input accordingly. Machine protection is provided by continuously
monitoring critical conditions and performing control overrides or safety shutdowns, if required.
Start-Stop System — The type of start-stop system is
selected by the customer. The most commonly used systems
are described below. Review the descriptions and determine
which system applies to your job.
SEMIAUTOMATIC START-STOP — In this basic system,
auxiliary equipment is wired into the machine control circuit and machine is started and stopped manually with the
machine Start and Stop switches. Two variations are used:
With Pilot Relays — The coils for the chilled/hot water and
condensing water pump starters (or other auxiliary equipment) are wired into the machine control circuit so that the
auxiliary equipment operates whenever machine operates. The
starter contacts and starter overloads remain in the external
pump circuits. The pump flow switch(es) and auxiliary starter
circuits are also wired into the machine control circuit and
must be closed for the machine to operate.
WithManualAuxiliaries — With this system, the auxiliaries
must be started manually and independently from the machine start, and they must be operating before the machine
can start. As with the pilot relay system above, the flow
switch(es) and auxiliary starter contacts are in the machine
control circuit and must be closed for the machine to
operate.
FULL AUTOMATIC START-STOP — This system is basically the same as the semiautomatic system with pilot relays described above. Machine and auxiliary start and stop,
however are controlled by a field-supplied thermostat, timer,
or other automatic device when the TS6 Local/Remote switch
is in the REMOTE position, and the machine Start switch
has been depressed.
Machine Control Panel — The 16DF standard con-
trol panel is shown in Fig. 10.
LEGEND
3CI — Three-Character Indicator
51RP — Refrigerant Pump Overcurrent Relay
51SP — Solution Pump Overcurrent Relay
88RP — Refrigerant Pump Electromagnetic
88SP — Solution Pump Electromagnetic
BZ — Alarm Buzzer
CX — Remote Control Auxiliary Relay*
DL — Door Latch
ET1,2 — Grounds
F0 — End-Contact Fuse
F1-5 — Enclosed Fuses
MCB1,2 — Main Circuit Breakers
NF1,2 — Line Noise Filters
PB1 — Start Pushbutton Switch
PB2 — Stop Pushbutton Switch
PK1 — Central Processing Unit (CPU) Board
PK2 — Input Terminal Module
PK3 — Output Terminal Module
RY1 — External Emergency Stop Auxiliary Relay
RY2-5 — Burner Safety Shutdown Auxiliary Relays
SK1-3 — Surge Suppressors
ST1 — Display Code Identification Sticker
SWR1,2 — Switching Regulators
T1 — Burner Safety Shutdown (‘‘Off’’ Delay Timer)
TB1-3 — Terminal Boards
TR1 — Transformer
TR2 — Direct Current Control Circuit
TR3 — Alternating Current Control Circuit Transformer
TS2-6 — Operation Switches
TS1 — Direct Current Power Supply (On/Off)
TX — Remote Control Circuit Auxiliary Relay*
*CX,TX auxiliary relays for remote operation are
optionally installed signals.
Contactor
Contactor
(see also Fig. 11)
Transformer
Fig. 10 — Control Panel
14
Status Indicator Sticker — The sticker shown in
Fig. 11 is located on the front of the control panel. It identifies the basic codes for machine operating status and safety
shutdown, as displayed by the 3-character indicator on the
front of the control panel.
NOTE: See Digital Temperature Display, page 16, and Adjustment Switches, below, for switch selections that display
temperatures being measured by the machine sensors as well
as the machine cumulative run time.
Adjustment Switches — These are located on the cir-
cuit board on the inside panel door.
TOGGLE SWITCHES (Fig. 12) — These are summarized
in Table 6 and discussed in greater detail in various sections
throughout this manual.
Table 6 — Control Panel Toggle Switches
SYMBOL TOGGLE SWITCH DESCRIPTION
TS1 On-Off Direct Current Power Supply
TS2 Auto.-Manual Dilution Valve
TS3 Cool-Heat Select Cool/Heat
TS4 Open-Close Capacity Control Valve
TS5 Auto.-Manual Capacity Control Valve
TS6 Remote-Local Operation
NOTES:
1. Time display selection shows thecumulative machine operating time inhours
on the panel door operating status indicator. With the capacity control valve
selection in the AUTO. position, momentarily depressing the switch to OPEN
displays the first 3 digits of the time, and depressing the switch to CLOSE
displays the last 2 digits and decimal. Example:
OPEN position indicates = 012
CLOSE position indicates = 345
Cumulative run time = 01234.5 hours
2. With capacity control valve selection in the MANUAL position, momentarily
depressing the switch to OPEN or CLOSE will move the burner fuel control
valve and air damper proportionally open or closed.
Fig. 12 — Control Panel Toggle Switches
Fig. 11 — Control Panel Status Indicator Sticker
15
SET POINT AND DIP (Dual In-Line Package) SWITCHES
(Fig. 13-16) — These switches are used to adjust chilled water and hot water capacity control temperature set points (also
see Automatic Capacity Control section, page 31); to select
the type of remote control signal; to display temperatures of
the various machine temperature control sensors; and for service selections.
Chilled/Hot Water Control Location — SW11 switch 2
(Fig. 16) determines whether the capacity controller will use
the chilled/hot water inlet nozzle sensor (UP position), or
the outlet nozzle sensor (DOWN position).
NOTE: DOWN is the typical selection.
Chilled Water Capacity Control TemperatureSetPoint — The
chilled water control temperature is determined by the setting on SW2 (Fig. 13, right side). The settings are increments of 1° C (1.8° F) from 0° to 9° C (0° to 16° F), and the
control temperature is the SW2 setting above a base temperature of 5 C (41 F), for an adjustable range of 5 to 14 C
(41 to 57 F). For example, a selection of 2 on SW2 would
be a setting of 2° C plus5C(7Ctotal) (3.6° F plus 41 F =
44.6 F total).
Hot Water Capacity Control Temperature Set Point — The
hot water control temperature is determined by the settings
on SW1 (Fig. 13, left side) and on SW10 switches 1 and 2
(Fig. 15). The SW1 settings are increments of 1° C (1.8° F)
from 0° C to 9° C (0° to 16° F). The SW10 1 and 2 selections are for a base temperature of either 40 C (104 F),
50 C (122 F), 60 C (140 F), or 70 C (158 F). The control
temperature is the SW2 setting above the selected base
temperature, for an adjustable range of 40 to 79 C (104 to
174 F). For example, a selection of 2 on SW1 and placing
both SW10 switches in the UP position would be a setting
of 2° C plus 70 C (72 C total) (3.6 F plus 158 F =
161.6 F total).
Remote ON/OFF Signal — When the Local/Remote Operation toggle switch (Fig. 12) is in the REMOTE position, SW11
switch 1 (Fig. 16) will determine whether the remote signal
is to be a remotely powered on/off voltage signal to the machine control circuit (UP position), or is from machine control circuit power through remote dry contacts (DOWN
position).
Digital Temperature Display — The temperatures being measured by the machine’s analog sensors will be displayed in
°C by the 3-character indicator on the front of the control
panel when DIP switch 6 on SW11 (Fig. 16) is placed in the
UPposition.OtherwisethisswitchshouldbeleftintheDOWN
position for normal operating status indication. The temperatures will be shown in 8 sequential displays, with the
first of the 3 characters indicating the channel (sensor) and
the second and third characters showing the temperature. The
first 6 channels indicate temperatures of 0° to 99 C (32 to
210 F) directly, and the seventh indicates, by code, 0° to 200
C (32 to 392 F). See Table 7.
Indicator LEDs — Fig. 17 shows the status of the ma-
chine’s light-emitting diode (LED) indicator lights for DIP
switch 5 of SW11 (Fig. 16).
Chilled and Hot Water Temperature Limit Settings on SW9
(Fig. 14) and Capacity Control Response Speed on SW10
(Fig. 15) — The purpose and selection of these settings are
SW1 — Hot Water Temperature Setting
SW2 — Chilled Water Temperature Setting
explained in the Automatic Capacity Control section.
Table 7 — Digital Temperature Display Codes
FIRST CHARACTER SECOND AND THIRD CHARACTERS
CHANNEL NUMBER (TEMPERATURE IN °C)
0 00 to 99 Chilled/hot water leaving temperature
1 00 to 99 Weak solution leaving absorber temperature
2 00 to 99 High-stage generator vapor temperature
3 00 to 99 Chilled/hot water entering temperature
4 — Not used at this time
5 — Not used at this time
6 — Not used at this time
7 Code display High-stage generator leaving solution temperature
CHANNEL 7
TEMPERATURE CODE
7
*Example: A display showing 7C3 means channel 7 measures 123 C (253.4 F).
SECOND CHARACTER
CODE
A 100 212
B 110 230
C 120 248
D 130 266
E 140 284
F 150 302
H 160 320
TEMPERATURE
CF
Fig. 13 — Load Water Temperature
Adjustment Switches
CONDITION SENSED
BASE
THIRD CHARACTER
This is the unit of temperature
in 1° C increments (1.8° F) added to
the base temperature*
16
Fig. 14 — Switch SW9
17
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