Dunham-Bush WCFX 30-30 User manual

Supplementary To
Form No: 6088A
-DUNNAM·!iUSM
Produc ts Thal Perf orm ...By people IM_io Care
Water· Cooled
Rotary Screw
Tandem
Water Chillers
SIS to 720 Tons
MO D EL:
WCFX 30 - 30
WCFX 30-33
WCFX 33-33
WCFX 33-36
WCFX 36-36

TABLE OF CONTENTS
1.0 GENERAL INFORMATION
1.1 RECEIVING AND INSPECTION.............. .. .......4
1.2 RIGGING AND MOVING. .. ...............................4
l.3 DIMENSIONAL DATA........... ~ .......................... .4
1.4 APPLICATIONPRECAUTIONS.......... ... ........ .. 4
1 .4 .I Water Connections .. ............................................4
1.4.2 Chilled Water Flow
.. .................. .... ..................... 4
1.4.3 Water Cooled Condenser.............
.. ... .. .................9
1.4.4 Condensing Water
Tr eatment....... .. .....................9
2.0 INSTALLATION
2.1 FOUNDATION ... .............................................. ... 10
2.2 VIBRATIONISOLATION .. ....... .. ....................... 10
2.3 WATER PIPING CONNECTIONS ............. .. ..... 10
2.4 ELECTRICAL WIRING ......... .. ..... ................... 10
2.S CONTROLS............................................... ... . ... . .. 13
2.
5.1 Connections........ .. ...................... .. .................... .. . 13
2.5.2 Settings........................................... .. ................... 13
2.6 REQUEST FOR START-UP
REPRESENTATIVE.....
.. ......... .. .... .. ....................13
3.0 OPERAT I ON
3.1 SYSTEM WATER FLOW RATE ... ...... .............. 14
3.2 SEASONAL SHUT -DOWN PR OCEDURE ...... .. 14
3.3 SEASONAL START-UP PROCEDURE..... .. .. ..... 14
3.4 SAFETY RELIEF VALVES............ .. . .. .... .. ......... 15
3.S REFRIG ERATI ON CYCLE... .. ........................... 15
3.6 OIL MANAGEMENT SYSTEMS.......... .... ... .. .... 15
3.7 HYDRAULIC CAPACITY CONTROL
SYSTEM.... .. ........................................ .. .............. 17
3.8 FREEZE PROTECTION . .... ........ ... .... .. ...............18
3.8.l Stand
by At Low Ambient Temperatures ............. 18
3.8.2 In Operation ......
.. ................................................ 18
3.8.3 During Maintenance.......................
.. ................. .. I8
4.0 ELECTRICAL
4.1 50/60HZELECTRICALDATA ....................... .... 19
4.2 WIRING DIAGRAM .. .. ....................................... 20
4.3 TYPICAL OPERATION....... .. ............................ 20
4.4 MICROCOMPUTER CONTROL L ER ........ ... .... 20
4.4.I To Di sp lay Data From The Menu........................ 23
4.4.2 To Reset
All Contr ol Points To Computer
Control
.... ............ .. .......................................... .. ..23
4.4.3 To Di
sp lay Alarms ........................................ .... ..23
4.4.4 To Become Authorized.....................
.. .............. .. .23
4.4.5 To Alter Setpoint Data.........................................23
4.4.6 To Calibrate Temperature And Pressure
Sensors............................
.. ................ .. ................ 24
4.4.7 To Set Date And Time ............
.. ........................... 24
4.4.8 To Display Data Without Accessing Operation......24
4.4.9 Unit Schedu
le Of Operation ............... .. ......... .. .......24
4.S CONTROL FUNC TI ONS .. .. ..................................25
4.5.l Chilled Water Pump Inte
rl o ck And Flow Switch .26
4.5.2 Customer Control Interlock..
.. ..............................26
4.5.3 Anti-Recycle Timer .............
.. .............. .. .............. 26
4.5.4 Part Wind Start Timer..........................................26
4.5.5 Load Contr
ol ........................................................26
4.5.6 Ramp Control .............................
.. ... .... ... .. ...........26
4.5.7 Current
Lim iting ......... .... ..................... .. .... .. .... .... 27
4.5.8 Staging Control...............................................
.. ...27
4.5.9 Modmotor Setback Control..............
.... ................27
4.5.I0 Evaporator Pressure Control .............
.. ................. 27
4.5. 11 Manual Lead-Lag Control....................................28
4.5.
12 Manual Load-Unload Control ........... .. .................28
4.5.13 Chilled Water Reset And Customer Control
4.5.14
4.5.
15
4 .5 .16
~~~r~::s·;;~~~·:: :: ::::: : : :::::::::: ::::: ::::: ::::::: : :::: :::: : : ::;: c·
Sump Heater Control ............... .. ........ .. ................29
Low Pressure Load Limit.............
.... .......... .. ........ 29
4.5.17 High Pressure Load Limit...... .. ................ .... ........ 29
4.6 SAFETY FUNCTIONS .. .. .. .................................... 29
4.6.1 Control Power Loss ............ .. .......... ...... ............... 29
4.6.2 Low Pressure Cut-off...........................................29
4.6.3 Evaporator Freeze Shutoff..
.. .............. .... .............. 29
4.6.4 High Pre ss ure Cut- Off ... .. .. ........... .. .....................30
4.6.5 Oil Level Sensor......................... .. ........................30
4.6.6 1-ligh Oii Temperature Thermostat .......................30
4.6.7 MotorTemperature Prot ec tor...... .. ...... . .. ..............30
4.6.8 Overload Protector............ ................... .. ......... .. ...30
4.6.9 Undcrvoltage Relay................. .... ......... .. .............. 31
4.6.10 SensorAlarm....................................... .. .............. 31
4.6. 11 No-Stop Alarm................................................... .. 31
4.6 .1 2 Low Differential Pressure Alarm............. .. ......... .. 31
s.o MAINTENANCE
5.1 GENERAL...... .. . .. ....... .... ................................... .. ...32 (
5.2 PERIODIC INSPECTION........................... .. .. .. ....32
5.3 MONTHLY INSPEC
TI ON.... ... .... ...................... .. 32
5.4 WATER SIDE CLEANING OF VESSELS......... .. 32
5.5 ELECTRICAL MALFUNCTION .........................34
S.6 CHARGING.............................
.... .......... .. ..............34
5.6.I Refrigerant Charge..................... ...... .. .. ..................34
5.6.2 Oil Charge.....................
.. ............. .. ........................34
5.7 TROUBLESHOOTING.........
... .... .. ....... .. ..............35
5.8
SAMPLE LOG SHEET.................... ... ......... .. .......37
6.0 RENEWAL PARTS.
6.1 COMPRESSOR & COMPRESSOR PARTS ... ... .. 38
6.2 WCFX TANDEM ELECTRICALPARTS .......... .. 39
6.3 UNIT MODEL NUMBER CODE ...... .. .. ................40
(

INTRODUCTION
This equipment is a factory built and tested packaged chiller designed fo r the
purpose
of cooling water orother non-corrosive liquid. T he liquid to be cooled
is to
be circulated through the tubes of a refrigerant evaporator where the
temperature is reduced to the desired level. The heat absorbed
by the
refrigerant
in the evaporator is rejected via the condenser where it raises the
temperature
of another liquid stream (usually water) being circulated through
the tubes. This heat is usually rejected
by a cooling tower or closed circuit
r cooler.
r
To assure satisfactory operation and to avoid damage to the unit, the
installation should be made by a qualified refrigeration mechanic. It is
assumed that the reader
of this manual and those who install, operate and
maintain this equipment have a basic understanding
of the principles of air
conditioning, refrigeration
and electrical controls. These instructions are
general in nature and are for standard catalog units. Non-standard units may
vary
in some respects from these instructions. .\
Your Dunham-Bush packaged chiller has been manufactured under a careful
quality control system. It has
been performance tested at the factory at
specified field operating conditions
as a final verification of reliability. If it is
installed, operated and maintained with care and attention to these
instructions, it will give many years
of satisfactory service.
- 3 -

Lo GENERAL INFORMATION
1.1 RECEIVING AND
INSPECTION
The unit should be inspected immediately, in
the presence of the carrier's representative, for
any evidence of damage during shipping. Any
damage should be noted on th e carrier's
delivery receipt before
it is signed. A damage
claim should then be
filed by the purchaser
against the delivering carrier
as all shipments
are made at the purchaser's
risk. The receiving
inspection instructions, sent with the
installation instructions, should also be
filled
out at this time and forwarded to the Dunham-
Bush Sales & Services Sdn Bhd.
1.2 RIGGING AND MOVING
Each unit has been carefully tested and
inspected at the factory where every
precaution was taken to ensure that it reaches
its destination
in perfect condition. It is very
important that the insta
ll e rs, movers, and
riggers use the same care
in handling the unit.
The unit
is designed to be lifted from the li fting
holes in the steel structural base. For proper
rigging, see Figure 1.2.
It
is important to protect the unit from damage
during storage, rigg
in g and installation.
Particular care should
q~ given to avoid
damage to controls
and pj~ing . Do not a ll ow
the unit to be used as a
lad~er or scaffold!
1.3 DIMENSIONAL DATA
Dimensional outline drawings and physical
data
of the packages are shown in Figures 1.3
and Table 1.3 respectively. Note especially the
space
and clearance requirements necessary for
servicing the unit.
1.4 APPL I CATION
PRECAUTIONS
The following instructions are intended to help
assure proper
and successful application of
your water chilling machines.
1.4.1 Water Conditions
Standard construction of the
evaporator
and condenser used in
Dunham-Bush model WCFX Tandem
chillers
is copper tubes with steel tube
sheets
and liquid heads.
These materials are generally suitable(
for use
with clean fresh water found in
most localities. However, minerals and
other con taminants found in some
water systems
may promote
aggressive attack on the tubes or tube
sheets, resulting
in failure with serious
consequences
for the entire package
chiller.
Because Dunham-Bush
has no control
over the condition
of the water used in
these machines, we can take no
responsibility for failure of tubes or
tube sheets due to water corrosion or
erosion. It is recommended that the
buyer obtain the services
of loca(
water treatment specialists to
prescribe water treatment.
1. 4.2 Ch i ll ed Water F low
- 4 -
The Dunham-Bush WCFX Tandem
Chiller
is designed for a constant
chilled water flow rate, even when the
cooling
load is varying. The machine
will generally perform satisfactorily
with steady
flow rates deviating from
design by as much as +I 0% I -50%.
However, varying water flow rates can

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-.. . l
RIGGING TO BE DO NE IN A MANNER Sp THAT NO STRAIN IS PLACED
ON UNIT CO MPONENTS OTHER THAN AT CABLE CONNECTION POINTS
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.. -. .'
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Note: Protect unit from cabl es .
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Z.o GENERAL INFORMATION
TABLE 1.3 PHYSICAL SPECIFICATIONS 50HZ
WCFX 30-30, 30-33, 33-33, 33-36, 36-36
UNIT MODEL 30-30 30-33 33-33 33-36 36-36
NOMINAL TONS
515 555 570 610 625
COMPRESSORS 1215(4) 1215(3)/1218(1) 1215(2)/1218(2) 1215(1)/1218(3) 1218(4)
RPM 2950 2950
2950 2950 2950
ELECTRICAL INFORMATION 400-3-50Hz
COMPRESSOR : RLA, EACH 155(4) 155(3)/186(1) 155(2)/186(2) 155(1)/186(3) 186(4)
1ST STEP INRUSH, EACH 360(4) 360(3)/446(1) 360(2)/ 446 (2) 360(1)/446(3) 446(4)
LRA,
EACH
991(4) 991(3)/1233(1) 991(2)/1233(2) 991(1)/1233(3) 1233(4)
UNIT : MCA (MIN. CIRCU IT AMPS)
659 698 729
760 791
MFS (MAX . ALLOW . FUSE) 800 800 900 900 900
EVAPORATOR MODEL· 2 NOS. l2 l2 l3 l3 M1
DESIGN PRESS. WATER SIDE (PSIG) 150
150 150 150 150
DESIGN PRESS.REFRIG. SIDE (PSIG)
300 300 300 300 300
WATER VOLUME, GALLONS (EACH) 46.6 46.6
49 .0 49.0 53 .2
-
MIN. GPM (1 PASS) 436 436 482 482
526
MAX. GPM (1 PASS) 2138 2138 2358 2358 2580
CONDENSER MODEL • 2 NOS.
J3 J3
K1 K1 K2
DESIGN PRESS. WATER SIDE (PSIG) 150 150 150 150 150
DESIGN PRESS. REFRIG. SIDE (PSIG)
300 300 300 300 300
WATER VOLUME, GALLONS (EACH) 54.9 54.9 59.1 59.1 61.2
MIN. GPM (2 PASS)
250 250
276 276 300
MAX. GPM (2 PASS) 1065 1065 1175 1175 1270
GENERAL INFORMATION
SHIPPING WT. LB . 23216 23532 23848 24537 25226
OPERATING WT. LB 25858 26232 26606 27446 28286
APPROX. REFRIG. CHARGE, 960 1008 1056 1104 1152
LB.R -22
Notes: a.)
Fouling factors for both cooler & condenser" 0. 00025
b.) The above performance data are based on standard vessels selection, consult faclory for olher mix-match vessel selection.
c.)
The above performance is based on 10'F range for condenser and chilled water temperalure.
- 6 -
I
ton is equal to 3.5168525 kilowatts

(
(
Z .. o GENERAL INFORMATION
TABLE 1.3 PHYSICAL SPECIFICATIONS 60HZ
WCFX 30-30, 30-~3, 33-33, 33-36, 36-36
UNIT MODEL 30-30 30-33 33-33 33-36 36-36
NOMINAL TON S 590 635 655 705 720
COMPRESSORS 1215(4) 1215(3
)/ 1218(1) 1215(2)/1218(2) 1215(1 )/ 1218(3) 1218(4)
RPM 3500 3500 3500 3500 3500
ELECTRICAL INFORMATION 460-3-60Hz
COMPRESSOR:RLA,EACH 155(4) 155(3)/186(1) 155(2)/186(2) 155(1 )/ 186(3) 186(4)
1S T STEPINRUSH, EACH 360(4) 36 0(3)/446(1) 360(2)/446(2) 360(1)/446(3) 446(4)
LRA,
EA CH 991 (4) 991 (3 )/ 1233(1) 991 (2 )/ 1233(2) 991 (1
)/ 1233(3) 1233(4)
UNIT : MCA {MIN. CIRCUIT AMPS) 659 698 729 760
791
MFS {MAX. ALLOW . FU SE) 800 800 900 900 900
EVAPORATOR MODEL - 2 NOS. L2 L2
L3 L3
M1
DESIGN PRESS. WATER SIDE (PSIG} 150 150 150 150 150
DESIGN PRESS. REFRIG. SIDE (PSIG) 300 300 300 300 300
WA TER VOLUME, GALLONS 60 60 64
64 75
MIN. GPM (1 PASS) 436 436
482 482 526
MAX . GPM (2 PASS) 2138 2138 2358 2358 2580
CONDENSER MODEL - 2 NOS.
J3 J3 K1 K1 K2
DESIGN PRESS. WATER SIDE (PSIG) 150 150 150 150 1
50
DESI GN PRESS. REFRIG. SI DE {PSIG) 300 300 3 00 300 300
WATER VOLUME,GALLONS
67
67 77 77 82
MIN. GPM {1 PASS) 250 250 276 276 300
MAX . GPM (2 PASS) 1065 1065
11 75 1175 1270
GENERAL INFORMATION
SHIPPING WT . LB. 23216 23532 23848 24537 25226
OPERATING WT . LB 25858 2
62 .)2 26606 27446 28286
APPROX. REFRIG. CHARGE, 960 1008 1056 1104 1152
L
B. R-22
Notes: a.) Fouling factors for both cooler & conde nser= 0.00025
b .} The above performance data are based on standard vessels selection, consult factory for other mix-match vessel selection.
c.) The above performance is based on 1o•F range for condenser and chilled water temperature.
- 7 -
Gallons Per Minute. 1 Gallon
=3,785 liter
1650 L/min, 99m3/h
8092 L/min, 486m3/h
4031 L/min, 242m3/h
946 L/min, 57m3/h

Z.o GENERAL INFORMATION
FIGURE 1.3 DIMENSIONAL DATA
WCFX 30-30, 30-33, 33-33, 33-36, 36-36
1 50'-
SUGGES TEO
CL (ARA NC£
f' OR TU BE
Ct.EAN!NG
(JTH (R ( NO
DIMENSIONAL CHART
EVAPORATOR
WAT ER CO NN.
"R"
CONDE NS(;R
WA T ER CONN. "S "
M QO(L MA TC HES 1
PASS I PASS 2 PA SS J PA SS
JO-JO
10· 10" 6" 6"
JO-JJ
.J.0. 10" 6" 6"
JJ..JJ
1 0· 10 · a· 6"
JJ -36 1
0· 10 · a· 6"
J6 - J6
12" 10· a· 6"
NO TE S:
1 - WATER PIPI NG TO BE SUP P OR T ED TO MINIMI ZE LOAD ON U NIT .
2 - ALL DIM EN SIONS ARE IN IN CHES.
A
22 J/<"
22 J/4"
22 J/4"
22 J/ 4"
23 J/ 4"
50/60 Hz
VESSEL l£NG IH (VI.):
VE SSH COO ( (( VAP /CONO)
(VAP CONN . CO NO CO NN. l
/J
L/ K M/R
' PASS 2
PASS (I./~)
l?J. 1&0· •eti•
1 PA S'S
2 P.ASS {R/H) 1 1.) '" 1 80" 1ao·
I P..t.S~
' 0~ J PASS
11r
1 19 · 1 79·
5 0'
98'
so ·- -i- ---- ee · ---- -i--
B c 0 E f
99•
9 •/8" II 1/ 4"
12· II 1
/4"
89 " 9 1 /8 ''
11 1/ 4" 12" 11 1 /4 "
99•
9 5/ a ··
12 J/ >6" 1
4"
12 J/ •6·
89" 9 5/8" 12 J/ 16"
14"
12 J/ 16·
90·
9 5/8 " 12 J/ 16"
14"
12 J/ 16"
3 - VEN T AN D DRAIN CONNECT I ONS PR OV1 DED ON EVAPO RAT OR AND COND ENSE R.
4 - SUFFIC I ENT ROOM MUS T BE AL LOWED FOR EV AP ORATOR AND COND EN SER WA TE R CO NNEC TI ONS .
5 36" OF FL EX IBLE CO ND UIT SHOULD BE USED.
6 - ALL WATER NOZZ LES ARE IPS, WITH VIC TA U LIC GR OO VES. SU I TABLE FOR VI CTAUUC COUPLINGS OR S LI P ON FLANGES.
7 - SP RING ISO LA TORS AR E OPTIONAL.
- 8 -
(
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(
Z.o GENERAL INFORMATION
cause control instability which will
result in undesirable system effects,
particularly poor control
of leaving
chilled water temperature.
If two-way
valves are used
to control flow
through cooling coils, some means
such as an automatic modulating valve
should be provided in the system to
maintain steady flow through the
evaporator.
If chilled water flow rate and/ or load
vary,
the variation must be controlled
so that return water temperature does
not vary at a rate exceeding 2°F per
minute.
If the chilled water system is arranged
for the dual purpose
of cooling and
heating, the evaporator must
incorporate valves
to prevent the flow
of hot water through it. This can be
done with either manual
or automatic
shutoff valves, but the method
of
control must be such that water
temperature entering the evaporator
never exceeds 90°F.
1.4.3 Water Cooled Condensers
The water cooled condenser is also
designed for constant water flow rate,
and should be supplied with the design
GPM ±10%. The condenser must be
protected from rapid changes
in
temperature as well. The maximum
allowable rate
of change in condenser
entering water is 1°F per minute.
Fluctuating flow rate
or temperature
will cause unstable control
of the
machine, resulting
in poor control of
leaving chilled water temperature. If a
cooling tower is used
to reject heat
from the condensing water loop, it
must
be controlled to provide an
entering condensing
water
temperature which does not change
more rapidly than 1°F/min. and does
not
go below 60°F. One or more of
the following methods may be used to
control the tower:
1.4.3.1 A modulating three-way valve
which by-passes tower sprays
at low load and
low ambient
temperature.
1.4.3.2 Tower fan staging in response
to a thermostat in the tower
sump. Fan thermostat should
have a differential
of at least
20°F to avoid short-cycling.
1.4.3.3 A modulating three-way valve
which by-passes t
he cooling
tower to blend warm leaving
condenser water with cold
tower water.
1.4.4 Condensing Water
Treatment
- 9 -
Condensing water tends to leave silt,
algae and mineral deposits in the
condenser tubes. This fouling
gradually decreases unit efficiency.
For this reason, a program
of water
treatment should
be employed. Also,
at regular intervals depending
on
water quality, the unit should be shut
down, condenser heads
re~oved and
tubes cleaned. See Section 5.4.

Z.o INSTALLATION
2.1 FOUNDATION
A flat, level concrete foundation or floor
capable
of supporting the weight of the unit
must
be provided. Weights are given in Figure
2.
l. The unit must be leveled to within 1/16"
per foot for proper operation.
2.2 VIBRATION ISOLATION
Where structure-borne vibrahon may be of
concern, it is recommended that the uni t be
mounted on vibration isolators. Rubber-in-
shear isolators or spring isolators are available
for this unit as opti
onal equipment. If spring
isolators are installed,
it is also necessary to
provide isolation
in condenser water and
chilled water pipes
by means of flexible
connectors and
in main power supply conduit
through use
of flexible conduit. Isolation of
piping and electrical conduit is desirable in any
event, to avoid noise transmission.
2.3 WATER PIPING
CONNECTIONS
Refer to Figures 1.3. for water p1pmg
connection locations. Note that the condenser
water inlet must be
on the bottom. If
necessary, evaporator or condenser heads can
be reversed, left to right or vice versa. Leaving
chilled water temp sensor must be located
in
leaving chilled water stream. After the unit has
been leveled
and isolators (ifany) installed and
adjusted, connect evaporator
and condenser
water piping. Piping must be properly
supported to avoid stress
on unit water
connections. Install
air vent valves in all high
connections on evaporator and condenser
heads. Install drain valves
in similar low points
to facilitate gravity draining
of the system. It is
important that water systems be cleaned before
start-up to avoid collecting debr
is in cooler and
condenser. The best way to do this
is ·to install
strainers
in both systems upstream of the unit.
After
filling systems with water, bleed trapped
air
from the various vent valves. Check for
proper
flo w ra tes by measur in g water pressure
drop across heat exchangers and reading GPM
from charts, Figure 2. 3. Compare measured
GPM's with values specified on purchase
order. Check
in Table 1.3. to see that (
evaporator
and condenser GPM's fall between
min . and max. lim its.
2.4 ELECTRICAL WIRING
In connecting power wiring to the unit, the
following precautions should be taken:
-
All fi eld wiring is to be in accordance with
the National Electric Code and must comply
with state
and local codes.
Check unit wiring for damage and
all
ter minal connections for tightness. Unit
terminal blocks are to be connected with (
copper conductors only,
si z ed per ampacity
listed on unit data plate.
-Connections to unit should
ma tch the unit
nameplate in volts, phase and Hertz.
Voltage must
no t vary beyond ±I 0% of
nameplate value and voltage imbalance
between phases must not exceed 2% at any
time during operation
of the unit.
-Phase sequence to connections
L1, Li, L3
shall be in that order. Check with Amprobe
phase sequence adapter PSA-1 or
equivalent.
-10 -

Z.o INSTALLATION
FIGURE 2.1 FLOOR LOADING DIAGRAM
WCFX 30-30, 30-33, 33-33, 33-36 & 36 -36
84 '
50/60 Hz

Z.o INSTALLATION
FI G URE 2.3 PRESSURE DROPS
1.a.) EVAPORATOR1 PASS (WCFX 30-30, 30-33, 33-33, 33-36 & 36-36)
ex:
w
..
..
>O
~ "
u..
0 ..
1-
u..
~ '
~ .
w '
ex:
::::> •
Ill
Ill
w
ex:
a.
J
'
1
L 3-
.---L I
L2 1
I
~ '
,,
I
, /,
~
v;
Vi/If
,,
,,
' I If r'
I
' '
I' '
,
If I,
If v
, I
'
WATER FLOW RATE -GPM
1.b.) CONDENSER 2 PASS (WCFX 30-30, 30-33, 33-33, 33-36 & 36-36)
..
..
)()
ex: ,.
w
l-
et "
;:
u..
0 ••
1-
u.
a.
0 ,
ex:
0
w •
ex:
::::>
Ill
Ill
w
ex:
a.
1
J3-i
I
I I
II
,
'I
,
l/ ,,
~
J.'
'/
II
,
,,
I '6
l l llf
'
I 11
1r rt
)I/
/'I
WATER FLOW RATE -GPM
-12 -
..--
Kl
2
~ K
50/60 Hz
(
· (
1 ft w.g. = 2,99 kPa

Z.o INSTALLATION
2.5 CONTROLS
2.5.1 Connections
Controls which are to be field installed
should be connected
in accordance
with the appropriate wiring diagram
accompanying the unit. The following
connections should be made where
applicable:
2.5.1.1 Connect a set of normally
open auxiliary contacts
from
chilled water pump contactor
into unit controls as shown
on
r unit wiring diagram.
2.5.1.2 Install a chilled water flow
switch (paddle type
recommended)
in straight
length
of chilled water piping
to avoid turbulence. Connect
in same electrical circuit as
2.5.1.1.
2.5.1.3 For control
of condensing
water pumps, connect
contacts supplied
in unit in
series with condensing water
pump starter
coil.
2.5.1.4 Connect an enable/disable
contact
into the unit controls
( as shown on the wiring
diagram. Closure
of this
contact enables the unit to
operate.
2.5.2 Settings
1'
All controls are factory set, however
operating control settings are not
always applicable under
all operating
conditions. For recommended control
settings, see wmng diagram
accompanying unit. Safety controls
must be set factory recommendations.
2.6 REQUEST FOR START·
UP REPRESENTATIVE
After the installation has been completed and
checked, contact the Dunham-Bush Sales &
Services for an authorized start-up
representative to perform the initial start-up
of
the Dunham-Bush packaged chiller. The
purchaser
must have competent service and
operati
ng personnel in attendance to assist in
the work involved, and also to be trained in the
service
and maintenance of this unit. (During
the warranty period, the manufacturer
is
responsible for parts only upon proof of
defective workmanship or manufacture).
Following this contact a representative
will be
sent to the customer. He
will inspect the
installation to determine whether it meets
Dunham-Bush requirements, perform the initial
start-up
of the installation, determine whether
it is in satisfactory operating condition, and
instruct the specified customer personnel in its
operation
and maintenance for the length of
time specified in the purchase contract.
NOTE :
Sump oil heaters should be energized for a
minimum of 24 hours and the oil sump
temperature must be at a
minimum of 100 °F
(38°C) prior to arrival
of start-up
representative. This
will ensure that the oil is
warm enough to vaporize any dissolved
refrigerant
and that the oil is within the normal
operating temperature range. Sump
oil heaters
are energized simply
by turning on the control
power switch.
WARNING
The compressor(s) should be started initially
ONLY under the direct supervision of an
Authorized Dunham-Bush Start-Up
Representative.
-13 -

J.o OPERATION
3.1 SYSTEM WATER FLOW
RATE
The quantity of chilled water being circulated
can
be measured quite accurately (±5%) by
determining the water pressure drop through
the evaporator and reading GPM from
evaporator pressure drop curve, Figures 2.3.
Connect reliable pressure gauges
to valves
installed in evaporator entering and leaving
water vent connections and read pressure
difference with chilled water pump in
operation. Condenser water flow rate can
be
measured in the same way. An alternate
method
of determining GPM is to measure
pressure difference from pump
inl et to outlet
and read GPM from the pump curve.
3.2 SEASONAL SHUT·
DOWN PROCEDURE
3.2.1 If the unit is to be shut down for a
prolonged period
(a month or more),
the power supply to the unit may be de-
energized to conserve energy.
3.2.2
The cooling tower may be drained to
avoid freezing. If the unit is located in
an area where the ambient temperature
constantly remains above freezing,
the
condenser need not be drained. It is
better
to leave the condenser and
evaporator
fi11ed with water during a
shutdown period.
If the unit is located
where ambient temperature w
ill be
below freezing, drain all water
thoroughly, removing
all vent and drain
plugs from both heads
of each vessel,
and blow out tubes with compressed
air.
NOTE: Simply draining is not
sufficient. Stagnant water may cause
serious corrosion.
3.2.3
It is recommended that an oil sample be
taken from each compressor and
submitted for laboratory analysis.
Dunham-Bush offers this service
in its
Oil Kare Program. This analysis should
be done
at the beginn in g and end of
each operating season, or every six
months
if the unit is used year round.
3.3 SEASONAL START-UP
PROCEDURE
When the unit is to be started up after being
shut down for a prolonged period:
3.3.1 Check unit for evidence
of rust or
corrosion. Clean surfaces and repaint as
necessary. Repair insulation
if
necessary.
3.3.2 Energize
power supply to unit. Unit
must be energized for 24 hours in order
to warm up compressor oil sump
before starting. Control circuit
power
switch should be off during this period
to prevent compressor operation. Clean
wa t er side heat transfer surface of
condenser and evaporator by removing
heads and brushing tubes.
3.3.3 Check water circuits to see that cooling
tower is ready for operation, and both
circuits are filled. Start pumps and
check for flow
in both cooler and
condenser.
3.3.4 Turn control circuit pow er switches on ,
turn compressor switch on, and pres(
reset on comput
er keyboard.
Compressor should start after start-up
clock times
out and leaving water
temperature should
be automatically
controlled. Check refrigerant charge
and check for normal suction and
discharge pressures.
3.3.5 Have a trained service mechanic check
the function
of all control setpoints.
Check signal lights for proper
operation.
3.3.6
Take oil sample from each compressor
and submit it for laboratory analysis.
-14 -

r
r
J.o OPERATION
3.4 SAFETY RELIEF
VALVES
Each pressure vessel is protected by a safety
relief valve as required by
ASME Code. Each
condenser has
one relief va lve. Local codes
may require that all safety relief valves
be
piped to the outdoors. Never install a hand
valve in a safety reliefvent line.
3.5 REFRIGERATION
CYCLE
Refer to Figure 3.5 for the piping schematic of
one system. Each vertical sc rew compressor
di scharges hot , high pressure gas through a
discharge check valve (A) into the condenser,
where it condenses outside tubes, rejecting
heat
to cooling tower water flowing ins id e the
tubes.
The li quid refrigerant drains to the
bottom
of the condenser and exits into the
economiz
er feed line.
The refrigerant flows thr oug h the eco nomizer
feed ball valve (B), dropping its pressure,
causing it to flash.
It then fl ows into the flash
economizer tank (C) which is at an
intermediate pressure between condenser and
evaporator. Liquid
is centrifugally separated
from
the flash gas and the liquid drains to the
bottom
of the tank, exits via the economizer
drain line, and passes through the economizer
drain ball valve (D).
Bot h economizer ball
valv
es are actuated by a Modutrol motor (U)
that adjusts fl ow to maintain an appropriate
refrigerant level in the evaporator, determined
by a liquid level float switch (V).
From the drain line, liquid refrigerant flows
into the flooded evaporator, where it boils,
cooling the water flowing irlside evaporator
tubes. Vap
or from the boiling refrigerant flows
up the suction pipes through a shut-o
ff va l ve
(E), suction check valve (F) and suction filt er
(G) (inside compressor) into the compressor
whe re it is compressed and sta rts the cycle
again.
Vapor flows from the top of flash economizer
into the compressor at the
vapor injection port ,
wh ich feeds it into the co mpr esso r part way
through the compression process. Check va l ve .
(H) prevents backflow at
shutdown in multi-
compressor units.
All compressors operate in
parallel
on a common evaporator and
condenser.
3.6 OIL MANAGEMENT
SYSTEMS (SEE FIG. 3.5)
The compressors are o il lubricated and
discharge a small amount
of oil mist along with
refrigerant. This oil is carried in
to the
evaporator. Oil rich refrigerant is r
et urned
from the evaporator through
two taps in the
she
ll , a filter-drier (L) between isolation valves
(K), and into a manifold that serves all
compressors. At each compressor, this oil
ri ch
liquid flows through a check valve (Q), sight
glass (R), and into a
jet pump (N) which feeds
into the compressor suction line.
Gas from
each compressor flows thro
ugh valve (S),
solenoid (P), and then drives the
jet pump .
Oil overflow feeds from the C4 port on the
compressor through an overflow valve (S),
sightglass (T), and check valve (Z), and is
shared between compressors by feeding
through the overflow feed solenoid
va lves (P)
into the operating compressors.
-15 -

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Ill
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Cll
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CON DENSER
I I \7 I I I \7 I I \ I ~
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w n
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3:
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JlU
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-- --0
EVAPORATOR
en
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'
en
I I
M
'-.../
I I
A-
DISCHARGE CHECK VA L VE
M -CHARGING VALVE
B- ECONOMIZER FEED VALVE
N-
OIL RETURN JET PUMP
C- FLASH ECONOMIZER TANK P - SOLENOID VALVE
0-
ECONOMIZER DRAIN VALVE
Q- OIL RETURN CHECK VALVE
E-
SUCTION SERVICE VALVE
R-
OIL RETURN SIGHT GLASS
F-
SUCTION CHECK VALVE
S- OIL OVERFLOWVALVE
G- SUCTION FIL TE R
T-
OIL OVERFLOWSIGHT GLASS
H - VAPOR INJECTION CHECK VALVE
U- MODUTROL MOTOR
J-
VAPOR INJECTION SHUTOFF VALVE
V-
LIQUID LEVEL FL OAT SW ITCH
Cll
(OPTIONAL) W-FEED LINE SIGHT GLASS
~
K- OIL RETURN VALVE X- VAPOR INJECTION SIGHT GLASS
en
L-
FILTER DRIER
Z-
OIL OVERFLOW CHECK VA LVE 0
:c
N
........
/

(
(
J.o OPERATION
3.7HYDRAULIC CAPACITY
CONTROL SYSTEM
(SEEFIG. 3.7.)
Each compressor has a hydraulic control
system
to position the capacity control slide
valve, thereby regulating compressor capacity.
It is composed of a normally closed solenoid
valve (A), a normally open solenoid valve (B),
an internal pressure regulating valve, a loading
rate control valve (C), and an unloading rate
control valve (D).
With valves A and B both energized (A open,
B closed) during normal compressor operation,
high pressure oil is directed
to the slide valve.
This pressure acts on the surface
of the slide
valve piston creating a force which is sufficient
to overcome the opposing spring force and to
move the valve in the direction of increasing
capacity. When the compressor is given a
"hold" command, valve A is de-energized
(closed) and slide valve movement is halted.
The internal pressure regulating valve allows
oil to bleed from the slide valve chamber
during the hold condition.
If valve B is then
de-energized (open}, the high pressure o
il
acting on the slide valve wi ll be vented to
suction, and the pressure in the s lid e valve
chamber w
ill be reduced. The slide valve
spring will now move the piston back toward
the minimum capacity position.
The rates of loading and unloading are
regulated by load rate needle valves C and D
respectively. The proper time for total slide
valve travel (loading
or unloading) is 40 ± 10
seconds. Load and unload rates will be slower
when the compressor is cool and at low head
than when hot and at high head.
To adjust load
or unload rate, remove the socket head 0 ring
plugs
to reach the needle valves. To decrease
rate, turn needle valve clockwise.
See table for a summary
of solenoid valve
operation vs. slide valve operation.
FIGURE 3.7 HYDRAULIC CONTROL SYSTEM
DISCHARGE ----.
BOSS
NORMALLY
· OPEN
UNLOADING
SOLENO ID 'B'
NOR"4ALLY
CLOSS ED
LOADING
SOLENOID 'A'
LOAD ING RATE
CON T ROL VALVE
'C'
UNLOADING RATE
CONTROL VALVE 'O'
SCHRADER VALV
-17 -
SLIDE VALVE POSITION
UNLOADING LOADING HOLD
SOLENOID VALVE CLOSED OPEN CLOSED
A (DE·ENERGIZEO) (ENERGIZED) (OE-ENERGIZED)
(NORMAL
LY ClOSEO)
SOLENOID VALVE OPEN
CL OSE CLOSED
B (DE·ENERGIZEO) (ENERGIZED) (ENERGIZED)
(NORMALLY OPEN)
TE RM INAL
B OX
SU CT IO N SE RVIC E
VALVE

3.o OPERATION
3.8 FREEZE PREVENTION
If water (or brine) is allowed to freeze within
the tubes and heads
of the evaporator or
condenser, severe damage will result; split and
leaking tubes and cracked and leaking heads.
Since this damage can be extremely costly and
is not covered by warranty, it is important to
be mindful
of freeze preven~ion. Three cases
deserve particular attention:
3.8.1 Standby at Low Ambient
Temperatures
If the unit is to stand idle at ambient
temperatures below 32°F, the water
should be drained from evaporator and
condenser. A head should be removed
from each vessel and the tubes blown
dry with compressed air. Gravity
draining the vessel through drains
in
heads may not be sufficient. If
evaporator or condenser are served
with a glycol solution, make sure the
freeze temperature
of the solution is
lower than expected minimum ambient
temperature.
3. 8.2 In Oper ati on
Freezing of water in cooler tubes is a
possibility
if chilled water flow stops
and
if the low suction pressure cutout
(normally set for 58 psig,
or 32°F
saturation) and the low water
temperature cutout both
fail. If the
chilled water flow switch and pump
interlock are properly applied (See
2.5.l.1 and 2.5.
l.2) the unit has four
protective devices which must
all fail
in order to freeze the evaporator in
operation. While this is unlikely, it is
important to see that all these devices (
are functional and properly calibrated.
3. 8.3 During Ma intenance
-18 -
In transferring refrigerant within the
unit,
or removing refrigerant from the
unit for maintenance purposes, it is
possible to freeze evaporator or
condenser tubes. Remember that
whenever the pressure
in a vessel is
reduced below 58 psig, if water is not
flowing, it
is possible to freeze tubes.
For this reason, it is a good precaution
to have water flowing in both vessels
whenever transferring refrigerant.

(
(
4o ELECTRICAL
4.1 ELECTRICAL DATA
UNIT
NOM.
MODEL
VOLTS
'l>HZ
60HZ 50 HZ 60HZ
WCFX 30-30 AU
AR 400 460
WCFX 30-33 AU AR 400 460
WCFX 33-33 AU
AR
400 460
WCFX 33-36 AU AR 400 460
WCFX 36-36 AU AR 400 460
-
NOTES: MCA - MINIMUM CI RC UIT AMPACI TY
MFS -MAXIMUM FUSE SIZE
RLA- RATED LOAD AMPS AT ARI COS
INR - FI RST STEP INRUSH AMPS
LRA -LOCKED ROTOR AMPS
UNIT
MCA
6S9
698
72 9
760
791
-19 -
50/60 Hz
EACH COMPRESSOR
MFS
RLA I NR
L RA
800 1 SS (4 ) 360 (4) 991 (4)
800 155(3) 360 (3) 991 (3)
186(1) 446 (1)
1233(1)
900 1SS (2) 360 (2)
991 (2)
186(2) 446 (2)
1233 (2)
900 1 SS (1) 360(1) 99 1 (1)
186(3) 446(3)
1233 (3)
900 186(4) 446 (4)
1233 (4)
-
.

4o ELECTRICAL
4.2 WIRING DIAGRAM
Figure 4.2 are typical wiring diagrams for a
Tandem chiller unit.
Th is may not be an
accurate representation of your unit. It is be st
to use the wiring diagram mounted in the
package control panel. A copy
of that diagram
is furnished with the unit
owner's manual.
4.3 TYPICAL OPERATION
In order to start a compressor, the fo ll owing
conditions must
be met:
-system voltage above undervoltage relay
(UVR) setting
-chilled water pump running
-chilled water fl ow switch made
-compressor circuit breakers on
-customer unit control contact closed
-control switch and compressor switches on
- reset pressed on microcomputer keypad
- power has been on the microcomputer for 15
minutes
- all safety conditions satisfied
-leaving chilled water temperature 2°F or
more above setpoint
A compressor is started by first energizing
lMl followed by IM2 after I second if step
start is activated (see 4.5.4). Otherwise,
both
contactors energize together. Anti-recycle time
of 15 minutes is initiated within the computer
at start.
When
the compressor starts, the micro-
comp
ute r monitors amperage by means of
ICT, voltage using 3T, .leaving water
temperature using
TS, and condensing
pressure. These inputs are used
to control the
loading and staging
of the compressor. The
compressors loading is controlled by pulsing
signals
to the load and unload soleno id s.
If the safety conditions are satisfied for the #2
compressor, at least I minute has elapsed since
starting #1 compressor, and leaving water
temperature remains above the deadband;
2Ml
and 2M2 will be activated by the micro-
computer,
(2M2 will close after 1 second
delay, if step start is desired.) #2 compressor
also has a
15 minute anti-recycle timer built
into the microcomputer. Loading
of the #2
compressor is contro
ll ed the same as
compressor #1. Compressors #3 and #4
operate in a sim
il ar manner.
To shut down the unit automatically, the
customer control contacts must be opened. To
shut down the unit manually, simply shut off (
the compressor switches. This will cause a no-
run alarm that must
be reset to restart the
compressor.
4.4 MICROCOMPUTER
CONTROLLER
This unit is controlled by a microcomputer
control system. The system is composed
of
four microcomputer boards, a display board
and analog and digital sensors. The following
sections describe the system and
how to
operate it.
The display board has a 20-key keypad and a 2 (
x 40 LCD display. The keypad and display can
be used to determine the status of the
compressor, and refrigeration system. Various
setpoints can also
be displayed and altered.
The status
of the machine can also be
monitored by a computer terminal either
locally
or remotely by a modem. The terminal
must
be able to handle RS232
communications.
For more information, Please
contact Dunham-Bush
Sa les & Services.
-20 -