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2Centrifugal Chillers IM 1044-2
Introduction
W = Water-cooled
General Description
Daikin Centrifugal Water Chillers are complete, self-contained, automatically controlled fluid chilling units.
Each unit is completely assembled and factory tested before shipment. Models WSC/WDC/WCC are coolingonly and Models HSC are cooling with heat recovery accomplished in a bundle of condenser tubes separate
from the cooling tower tube bundle.
In the WSC and HSC series, each unit has one compressor connected to a condenser and evaporator. The WDC
series is equipped with two compressors operating in parallel on a single evaporator and condenser. The WCC
series is equipped with two compressors, each operating on one refrigerant circuit of a two circuit evaporator and
condenser. Information in this manual referring to WSC and WDC also applies to WCC and HSC units except
where specifically noted.
The chillers use refrigerant R-134a to reduce the size and weight of the package compared to negative pressure
refrigerants, and since R-134a operates at a positive pressure over the entire operation range, no purge system is
required. The controls are pre-wired, adjusted and tested. Only normal field connections such as piping, electrical
and interlocks, etc. are required, thereby simplifying installation and increasing reliability. Most necessary
equipment protection and operating controls are factory installed in the control panel.
The basic sizes of units are the 063, 076, 079, 087, 100, 113 and 126. They provide a cooling capacity range from
200 to 2700 tons. In this manual all references to the WSC models will equally apply to other models unless
specifically referenced otherwise.
High Voltage Models
Certain 100, 113, and 126 size WDC and WCC units are available in high-v oltage (10/11kV). These m odels will
have different dimensions, weights, and installation details than the standard low/medium voltage models. See
your Certified Dimension Drawing for details specific to your unit. See page 25 for the procedure to mount the
terminal box on 10/11 kV units.
Application
The procedures presented in this manual apply to the standard WSC/WDC/WCC family of chillers and HSC
heat recovery chillers. Refer to the Operating Manual, OM CentrifMicro-II for details of operation of the
MicroTech II unit controller (latest version available on www.DaikinApplied.com).
All Daikin centrifugal chillers are factory tested prior to shipment an
a factory trained Daikin service technician. Failure to follow this startup procedure can affect the equipment
warranty. The standard limited warranty on this equipment covers parts that prove defective in material or
workmanship. Specific details of this warranty can be found in the warranty statement furnished with the
equipment.
Cooling towers used with Daikin centrifugal chillers are normally selected for maximum condenser inlet water
temperatures between 75°F and 90°F
standpoint of energy reduction, but
temperature and cooling tower fan control, consult Daikin catalog CAT 605, Applications Section, available on
www.DaikinApplied.com
heat recovery function is controlled externally to the chiller as explained later in this manual.
. Heat recovery models, HSC, basically operate the same as cooling-only units. The
(24°C and 32°C). Lower entering water temperatures are desirable from the
a minimum does exist. For recommendations on optimum entering water
d must be initially started at the job site by
W D C 063
Chiller Model, Based on
H = Heat Recovery
D = Dual Compressor
S = Single Compres sor
C = Dual, Counterflow
Impeller Diameter
Centrifugal Compr esso r
IM 1044-2 Centrifugal Chillers 3
Installation
Evaporator
Rigging
(6) Av ailable
Compressor
Mounting Optional
Operator
Panel
Receiving and Handling
The unit should be inspected immediately after receipt for possible damage.
All Daikin centrifugal water chillers are shipped FOB factory and all claims for handling and shipping damage
are the responsibility of the consignee.
I
nsulation corners from the evaporator's rigging hole locations are shipped loose and should be glued in place
after the unit is finally placed. Neoprene vibration pads are also shipped loose. Check that these items have been
delivered with the unit.
If so equipped, leave the shipping skid in place until the unit is in its final position. This will aid in handling the
equipment.
Extreme care must be used when rigging the equipment to prevent damage to the control panels or refrigerant
piping. See the certified dimension drawings included in the job submittal for the center of gravity of the
unit. Consult the local Daikin sales office for assistance if the drawings are not available.
T
he unit can be lifted by fastening rigging hooks to the outermost four rigging eyes (see Figure 1). Spreader bars
must be used between the rigging lines to prevent damage to the control panels, piping and motor terminal boxes.
Figure 1, WSC Major Component Locations
Locations
Condenser
Compressor and
Lubrication Control
Panel, At Rear
Unit
Control
Panel
Interface
Rigging
Locations
(6) Av ailable
Starter/VFD,
4 Centrifugal Chillers IM 1044-2
Condenser
Valves
Rigging
Oil Sump,
Pump, Heaters
Motor
Figure 2, WDC Major Component Location
Terminal Box
Eyes
Condenser
Dual Relief
Common Oi l
Cooler W ater
Connections
Rigging
Eyes
Lubrication &
Compressor
Control Boxes
Notes:
1. Chilled water and condenser connection location can vary. Check markings on unit or consult unit certified drawings for connection
locations on specific units.
2. WCC two-circuit units have separate evaporator and condenser relief valves on each circuit.
Location and Mounting
The unit must be mounted on a level concrete or steel base and must be located to provide service clearance at
one end of the unit for possible removal of evaporator tubes and/or condenser tubes. Evaporator and condenser
tubes are rolled into the tube sheets to permit replacement if necessary. The length of the vessel should be allowed
at one end. Doors or removable wall sections can be utilized for tube clearance. Minimum clearance at all other
points, including the top, is 3 feet (1 meter). The National Electric Code (NEC) can require four feet or more
clearance in and around electrical components and must be checked.
The chillers are designed for indoor installation only. Special procedures must be executed to prevent damage if
freezing indoor temperatures are possible.
IM 1044-2 Centrifugal Chillers 5
Operating/Stan dby Limits
Equipment room operating temperature:
40°-104°F (4.4°-40°C)
Equipment room temperature, standby,
Equipment room temperature, standby,
Maximum entering condenser water
Maximum entering condenser water
job-specific design
Minimum entering condenser water
Minimum leaving chilled water
temperature:
Minimum leaving chilled fluid temperature
Maximum entering chilled water
Maximum oil cooler or VFD entering
temperature:
Minimum oil cooler/VFD entering
temperature:
with water in vessels and oil coole r :
without water in vessels and oil cooler:
temperature, startup:
temperature, operating:
temperature, operating:
with correct anti-freeze fluid:
temperature, operating:
40°-104°F (4.4°-40°C)
0°F-122F (-18°C-50°C)
design + 5°F (2.7°C)
temperature
see following page.
38°F (3.3°C)
15°F (9.4°C)
90°F (32.2°C)
80°F (26.7°C)
42°F (5.6°C)
Vibration Pads
The shipped-loose neoprene vibration pads should be located under the corners of the unit (unless the job
specifications state otherwise). They are installed to be flush with the sides and outside edge of the feet. Most
WSC units have six mounting feet although only the outer four are required. Six pads are shipped and the installer
can place pads under the middle feet if desired.
Mounting
Make sure that the floor or structural support is adequate to support the full operating weight of the complete unit.
It is not necessary to bolt the unit to the mounting slab or framework; but should this be desirable, 1 1/8" (28.5
mm) mounting holes are provided in the unit support at the four corners.
Note: Units are shipped with refrigerant and oil valves closed to isolate these fluids for shipment.
Valves must remain closed until start-up by the Daikin technician.
Nameplates
There are several identification nameplates on the chiller:
• The unit nameplate is located on the side of the Unit Control Panel. It has a Style No. XXXX and Serial N
XX. Both are unique to the unit and will identify it. These numbers should be used to identify the unit for
XX
service, parts, or warranty questions. This plate also lists the unit refrigerant charge.
• Vessel nameplates are located on the evaporator and condenser. Along with other information, they have a
National Board Number (NB) and serial number, either of which identify the vessel (but not the entire unit).
• A compressor nameplate is located on the compressor itself and contains identification numbers.
System Water Volume
All chilled water systems need adequate time to recognize a load change, respond to that load change and
stabilize, without undesirable short cycling of the compressors or loss of control. In air conditioning systems, the
potential for short cycling usually exists when the building load falls below the minimum chiller plant capacity or
on close-coupled systems with very small water volumes.
Some of the things the designer should consider when looking at water volume are the minimum cooling load, the
minimum chiller plant capacity dur ing the low load period and the desired cycle time for the compressors.
6 Centrifugal Chillers IM 1044-2
o.
Assuming that there are no sudden load changes and that the chiller plant has reasonable turndown, a rule of
thumb of “gallons of water volume equal to two to three times the chilled water gpm flow rate” is often used.
A properly designed storage tank should be added if the system components do not provide sufficient water
volume.
Low Condenser Water Temperature Operation
When the ambient wet bulb temperature is lower than design, the condenser water temperature can be allowed to
fall. Lower temperatures will improve chiller performance.
Up to 600 Tons
Daikin centrifugal chillers up to 600 Tons are equipped with electronic expansion valves (EXV) and will start
and run with entering condenser water temperatures as low as shown in Figure 3 or as calculated from the
following equation on which the curves are based.
Figure 3, Minimum Entering Condenser Water Temperature (EXV)
Minimum Enterin g Conden ser Water Temp erature - 10 F Range
65.0
60.0
55.0
50.0
ECWT, F
45.0
40.0
35.0
30.0
0 10 20 30 40 50 60 70 80 90 100 110
M
in. ECWT = 5.25 + 0.88*(LWT) - DT
44
LChWT
42
LChWT
•ECWT = Entering condenser water temperature
•LWT = Leaving chilled water temperature
•DT
= Chilled Water Delta-T at full load
FL
•PLD = The percent chiller load point to be checked
Percent Load
(PLD/100) + 22*(PLD/100)2
FL*
For example; at 44°F LWT, 10 degree F Delta-T, and 50% full load operation, the entering condenser water
temperature could be as low as 44.5°F. This provides excellent operation with water-side economizer systems.
Over 600 Tons
Chillers over 600 Tons are equipped with thermal expansion valves (TXV) and will start and run with entering
condenser water temperatures as low as calculated by the following equation and shown in the chart following.
Min. ECWT = 7.25 + LWT– 1.25* DT
•ECWT = Entering condenser water temperature
•LWT = Leaving chilled water temperature
•DT
•PLD = The percent chiller load point to be checked
IM 1044-2 Centrifugal Chillers 7
= Chilled Water Delta-T at full load
FL
(PLD/100) + 22*(PLD/100) 2
FL
Figure 4, Minimum Entering Condenser Water Temperature (TXV)
Mini m um Ent er ing Condenser Wa t er Tem pe r at ur e - 10 F Range
30.0
35.0
40.0
45.0
50.0
55.0
60.0
65.0
0102030405060708090100110
Percent Load
ECWT, F
44 LChWT
42 LChWT
46 LChWT
For example; at 44°F LWT, 10 degree F Delta-T, and 50% full load operation, the entering condenser water
temperature could be as low as 50.5°F. This provides excellent operation with water-side economizer systems.
Depending on local climatic conditions, using the lowest possible entering condenser water temperature may
be more costly in total system power consumed than the expected savings in chiller power would suggest, due
to the excessive fan power required.
Cooling tower fans must continue to operate at 100% capacity at low wet bulb temperatures. A s chi ller s are
selected for lower kW per ton, the cooling tower fan motor power becomes a higher percentage of the total
peak load chiller power. Daikin's Energy Analyzer program can optimize the chiller/tower operation for
specific buildings in specific locales.
ven with tower fan control, some form of water flow control, such as tower bypass, is recommended.
E
Figure 5 illustrates two temperature actuated tower bypass arrangements. The “Cold Weather” scheme provides
better startup under cold ambient air temperature conditions. The check valve may be required to prevent
entraining air at the pump inlet.
Figure 5, Bypass, Mild Weather Operation
8 Centrifugal Chillers IM 1044-2
Bypass, Cold Weather Operati o n
Water Piping
CAUTION
!
Water Pumps
Avoid the use of 3600/3000-rpm (two-pole motor) pump motors. It is not uncommon to find that these pumps
operate with objectionable noise and vibration.
It is also possible to build up a frequency beat due to the slight difference in the operating rpm of the pump
motor and the Daikin centrifugal motor. Daikin encourages the use of 1750/1460 rpm (four-pole) pump motors.
Vessel Drains at Start-up
Unit vessels are drained of water in the factory and are shipped with the drain plugs in the heads removed and
stored in the control panel or with open ball valves in the drain hole. Be sure to replace plugs or close the valves
prior to filling the vessel with fluid.
Evaporator and Condenser Water Piping
All evaporators and condensers come standard with Victaulic AWWA C-606
groove nozzles (also suitable for welding), or optional flange connections. The
installing contractor must provide matching mechanical connections or
transitions of the size and type required.
Victaulic connections are AWWA C-606 on 14-inch and larger sizes. Field
supply transitions if Victaulic brand AGS® (Advanced Groov e System) type
grooves are used on the field piping. Note: Do not use PVC piping.
The tower connections on heat recovery units are always the inboard pair of
connections. In the figure to the right, the condenser connections are “left-hand”
when viewed from the front of the unit (Unit Control Panel and Interface Panel
side), so in this case, the right-hand condenser connections would be for the
tower. If the condenser connections were on the other end (“right-hand”), the
tower connections would be the left-hand pair of connections.
Note: Certain WSC units with a 2-pass configuration and copper tubing may
have an “over/under” connection configuration on the evaporator, rather than the side-by-side configuration
shown here. Consult Certified Drawings for exact configuration and dimensions.
Important Note on Welding
If welding is to be performed on the mechanical or flange connections, remove the solid-state temperature sensor
and thermostat bulbs from the wells to prevent damage to those components. Also properly ground the unit or
severe damage to the MicroTech II unit controller can occur.
Note: ASME certification will be revoked if welding is performed on a vessel shell or tube sheet.
Water pressure gauge connection taps and gauges must be provided in the field piping at the inlet and outlet
connections of both vessels for measuring the water pressure drops. The pressure drops and flow rates for the
various evaporators and condensers are job specific and the original job documentation can be consulted for this
information. Refer to the nameplate on the vessel shell for identification.
Be sure that water inlet and outlet connections match certified drawings and stenciled nozzle markings. The
condenser is connected with the coolest water entering at the bottom to maximize subcooling.
When common piping is used for both heating and cooling modes, care must be taken to provide that water flowing through
the evaporator cannot exceed 110°F which can cause the relief valve to discharge refrigerant or damage controls.
The piping must be supported to eliminate weight and strain on the fittings and connections. Piping must also be
adequately insulated. A cleanable perforated basket strainer with 0.125-in perforations and 40 % open area must
be installed in the evaporator water inlet line. Sufficient shutoff valves must be installed to permit draining the
water from the evaporator or condenser without draining the complete system .
IM 1044-2 Centrifugal Chillers 9
Victaulic Couplings
I in. (25mm) NPT flow
Tee
Use the following steps when installing Victaulic couplings:
1.Check for smooth pipe between the pipe end and the groove. Remove any indentations, projections, or
weld seams. Failure to do this can result in a leaking joint.
2.Apply a thin coat of Victaulic or silicon lubricant to the gasket lips and exterior.
3.Position the gasket over the pipe end without overhanging the pipe.
4.Join the pipes together and slide the gasket into position, centering it between the grov es.
5.Install the housing halves over the gasket, check that the housing’ keys engage the groves on both pipes.
6.Install the bolts and thread the nuts on hand tight. Make sure that the oval heads of the bolts seat properly
in the bolt holes.
7.Tighten the nuts evenly by alternating sides until metal to metal contact is made on the housing bolt pads
e sure that the housing keys completely engage the pipe grooves.
Mak
Flow Switch
A water flow switch must be installed in the vessel outlet piping to signal the presence of adequate water flow
to the vessels before the unit can start. They also serve to shut down the unit in the event that water flow is
interrupted to guard against evaporator freeze-up or excessive discharge pressure.
Thermal dispersion flow switches are available from Daikin as a factory-mounted option. It is
mounted in an evaporator and condenser water nozzle and factory wired.
A paddle type flow switch can be supplied by the owner for field mounting and wiring.
Figure 6, Flow Switch Mounting
Flow direction marked
on switch
.
switch connection
f flow switches, by themselves, are used, electrical connections in the Unit Control Panel must be made from
I
the common T3-S terminal to terminal CF for the condenser switch and T3-S to terminal EF for the evaporator
switch. See Figure 19, Field Control Wiring Diagram on page 32. The normally open contacts of the flow
switch must be wired between the terminals. Flow switch contact quality must be suitable for 24 VAC, low
current (16ma). Flow switch wire must be in separate conduit from any high voltage conductors (115 VAC and
higher).
1. A segmented 3-inch paddle (1, 2, and 3 inches) is furnished mounted, plus a 6-inch paddle loose.
2. Flow rates for a 2-inch paddle trimmed to fit the pipe.
3. Flow rates for a 3-inch paddle trimmed to fit the pipe.
4. Flow rates for a 3-inch paddle.
5. Flow rates for a 6-inch paddle
6. There is no data for pipe sizes above 8-inch. A switch minimum setting should provide protection against no
flow and close well before design flow is reached.
Alternatively, for a higher margin of protection, normally open auxiliary contacts in the pump starters can be
wired in series with the flow switches as shown in Figure 19, Field Control Wiring Diagram on page 32.
Freeze Notice: Neither the evaporator nor the condenser is self-draining;
Both must be blown out to help avoid damage from freezing.
The piping should also include thermometers at the inlet and outlet connections and air vents at the high points.
The water heads can be interchanged (end for end) so that the water connections can be made at either end of the
unit. If this is done, new head gaskets must be used and control sensors relocated.
In cases where the water pump noise can be objectionable, vibration isolation sections are recommended at both
the inlet and outlet of the pump. In most cases, it will not be necessary to provide vibration eliminator sections in
the condenser inlet and outlet water lines. But they can be required where noise and vibration are critical.
Cooling Towers
The condenser water flow rate must be checked to be sure that it conforms to the system design. Some form of
temperature control is also required if an uncontrolled tower can supply water below about 65°F (18°C). If tower
fan control is not adequate, a tower bypass valve is recommended. Unless the system and chiller unit are
specifically for condenser bypass or variable condenser flow is not recommended since low condenser flow rates
can cause unstable operation and excessive tube fouling.
The condenser water pumps must cycle on and off with the compressor. See Figure 19, Field Control Wiring
Diagram on page 32 for wiring details.
Tower water treatment is essential for continued efficient and reliable unit operation. If not available in-house,
competent water treatment specialists can be contracted.
Heat Recovery Chillers
HSC heat recovery chillers control the chilled water leaving temperature. The cooling load determines
compressor loading and unloading, the same as in a conventional chiller. A heat recovery chiller’s control
algorithms are identical to a conventional cooling-only chiller.
The temperature of the hot water being supplied from the recovery condenser to the heating load is established by
manipulating the cooling tower water temperature. The 3-way cooling tower bypass valve is controlled by the
heating water inlet temperature to the recovery bundle of the condenser. Based on the signal the 3-way valve gets
from the heating hot water sensor, it will bypass sufficient water around the tower to force the tower condenser
water loop high enough for the recovery bundle to produce the desired hot water temperature.
The chilled water and its control system do not sense that the condensing pressure and condenser water
temperatures are being regulated in this manner.
IM 1044-2 Centrifugal Chillers 11
EVAPORATOR
TOWER
CONDENSER
RECOVERY
CONDENSER
AUXILIARY
HEATER
HEAT LOAD
TC
TC
COOLING
LOAD
OPEN
CIRCUIT
TOWER
HEAT RECOVERY
CHILLER
LEGEND
TC TEMPERATURE CONTROL POINT
PUMP
Figure 7, Heat Recovery Schematic
12 Centrifugal Chillers IM 1044-2
Field Insulation Guide
Figure 8, Insulation Requirements, Cooling-only Units
IM 1044-2 Centrifugal Chillers 13
14 Centrifugal Chillers IM 1044-2
MWB Cover
lb (kg)
Physical Data and Weights
Evaporator
The standard insulation of cold surfaces includes the evaporator and non-connection water head, suction piping,
compressor inlet, motor housing, and motor coolant outlet line.
Insulation is UL recognized (File # E55475). It is 3/4" thick AB S/P VC fl ex ib le fo a m with a skin. The K factor is
0.28 at 75°F. Sheet insulation is fitted and cemented in place forming a vapor barrier, then painted with a resilient
epoxy finish that resists cracking.
The insulation complies to, or has been tested in accordance, with the following:
ASTM-C-177 ASTM-C-534 T y pe 2 UL 94-5V
ASTM-D-1056-91-2C1 ASTM E 84 MEA 186-86-M Vol. N
CAN/ULC S102-M88
Refrigerant-side design pressure is 200 psi (1380 kPa) on WSC/WCC/HSC units and 180 psi (1242 kPa) on WDC
units. Water-side is 150 psi (1034 kPa) on all.
In the event insulation is to be field-installed, none of the cold surfaces identified above will be factory insulated.
Required field insulation is shown beginning on page 13. Approximate total square footage of insulation surface
required for individual packaged chillers is tabulated by evaporator code and can be found below.
1. Water capacity is based on standard tube configuration and standard heads and may vary depending on tube counts.
2. Vessel weight includes the shell, maximum tubes, and standard heads, no refrigerant.
3. MWB, marine water box, weight add is the water box weight minus a standard dished head weight.
WSC WDC WCC
Water
Volume
gal (L)
Insulation
Area
sq ft (m
2
)
Vessel Dry
Weight
lb (kg)
Add for
MWB
lb (kg)
Only,
Weight
Number
of Relief
Valves
IM 1044-2 Centrifugal Chillers 15
Condenser
Pumpdown
lb. (kg)
Water
gal. (L)
Number of
Valves
With positive pressure systems, the pressure variance with temperatu re is alway s pred ictabl e, an d the vesse l
design and relief protection are based upon pure refrigerant characteristics. R-134a requires ASME vessel design,
inspection and testing and uses spring-loaded pressure relief valves. When an over pressure condition occurs,
spring-loaded relief valves purge only that refrigerant required to reduce system pressure to their set pressure, and
then close.
Refrigerant side design pressure is 200 psi (1380 kPa) on WSC/WCC/HSC units and 225 psi (1552 kPa) on WDC
units. Water side design is 150 psi (1034 kPa) on all.
Pumpdown
To facilitate compressor service, all Daikin centrifugal chillers are designed to permit pumpdown and
isolation of the entire refrigerant charge in the unit’s condenser. Dual compressor units and single compressor
units equipped with the optional suction shutoff valve can also be pumped down into the evaporator.
T
able 3, Condenser Physical Data
Condenser
Code
C1809 X 597 (271) 43 (162) 1887 (856) 2
C1812 X 845 (384) 44 (166) 2050 (930) 2
C2009 X 728 (330) 47 (147) 1896 (860) 2
C2012 X 971 (440) 62 (236) 2528 (1147) 2
C2209 X 822 (372) 73 (278) 2596 (1169) 2
C2212 X 1183 (537) 76 (290) 2838 (1287) 2
C2216 X 1489 (676) 114 (430) 3861 (1751) 2
C2416 X 1760 (799) 143 (540) 4647 (2188) 2
C2609 X 1242 (563) 83 (314) 2737 (1245) 2
C2612 X 1656 (751) 111 (419) 3650 (1660) 2
C2616 X 2083 (945) 159 (603) 5346 (2425) 2
C3009 X 1611 (731) 108 (409) 3775 (2537) 2
C3012 X 2148 (975) 144 (545) 5033 (3383) 2
C3016 X 2789 (1265) 207 (782) 6752 (3063) 4
C3612 X 2963 (1344) 234 (884) 7095 (3219) 2
C3616 X 3703 (1725) 331 (1251) 9575 (4343) 4
C3620 X 4628 92100) 414 (1567) 12769 (5797) 4
C4212 X 3796 (1722) 344 (1302) 9984 (4529) 2
C4216 X 5010 (2273) 475 (1797) 12662 (5743) 4
C4220 X 5499 (2494) 634 (2401) 17164 (7785) 4
C4220 X 5499 (2497) 634 (2400) 17964 (8156) 4
C4812 X 4912 (2228) 488 (1848) 12843 (5826) 4
C4816 X 5581 (2532) 717 (2715) 18807 (8530) 4
C4820 X 7034 (3191) 862 (3265) 23106 (10481) 4
C4820 X 8307 (3768) 727 (2753) 18907 (8576) 4
1.Condenser pumpdown capacity based on 90% full at 90°F.
2.Water capacity based on standard configuration and standard heads and may vary depending on tube counts.
3.See Relief Valves section for additional information.