Zurn Wilkins ZW204 Manual

Installation Troubleshooting Maintenance Instructions
Model ZW204
Non-Modulating Float Valve
1 1/4", 1 1/2", 2", 2-1/2", 3", 4", 6", 8" & 10"
to the inlet of the main valve. Port A should be connected to the
main valve cover (or accelerator pilot cover if installing an 8 or
10 inch valve.)
Note: When mounting the oat pilot above the main valve,
verify pressure at the oat pilot is 5 psi or greater to ensure
proper operation.
7. Zurn Wilkins valves are designed to operate in both the verti-
cal and horizontal positions. However, it is recommended that
ZW209 6” and larger, be installation in the horizontal position.
The horizontal positioning of the larger valves avoids premature
wear due to the mass of plunger assemblies as well as allows
for greater accessibility during annual inspections, and mainte-
nance.
START-UP
CAUTION: To prevent personnel injury and damage to
equipment check that downstream venting is adequate pri-
or to start-up and test procedures. If the main valve closes
too fast it may cause surging in upstream piping.
1. Open isolation valves (2) in the pilot system (see ZW204
schematics).
2. Slowly open the upstream shutoff valve only enough to ll
main valve assembly and pilot system. Prior to pressurizing the
valve assembly it is also recommended that a ZPI valve position
indicator be installed to aid in verifying proper valve movement.
3. As the valve is lling with water, it is necessary to bleed the
main valve and pilot system of air. To vent air, partially open or
loosen the highest plugs or ttings in the system. The ZPI valve
position indicator is a great location, as it has a test cock at the
top to vent air pressure. It may be necessary to bleed system
more than once. After removal of air in the system tighten all
loose ttings.
4. If valve is equipped with speed controls (O or L on ZW204
schematic) it is necessary to back out the set screw a minimum
of 3 turns from initial set point.
5. At this point with the upstream shutoff valve partially open,
slowly open the downstream shut off valve. Flow will begin to
occur and pressure should build up in valve and eventually
stabilize.
6. Next it is advisable to ow water through the valve to ensure all
air has escaped from system.
DESCRIPTION
The Zurn Wilkins Model ZW204 Non-Modulating Float Operated
Control Valve is an automatic control valve designed to be fully
open or fully closed in response to the position of the oat. The
oat ball will be placed in a tank where it will be raised or lowered
by the uid level. The valve will be fully open when the uid level is
at a preset low point and will fully close when the uid level is at a
preset high point. If the oat valve is being used to ow water out
of instead of into the reservoir, the oat pilotry can be congured
to have the valve fully open at a preset high point and fully closed
at a preset low point. If desired, switch line from port A to B on
the oat valve and plug port A. The Float Pilot valve is set up for
remote liquid level control as standard. With the VM option, the
oat pilot can be mounted on the valve.
NOTE: Flushing of all pipe lines is to be performed to remove
all debris prior to installing valve.
1. Install a control valve, orice, or other ow restricting device
downstream of the ZW204 if discharge pressure is greater than
20 psi. This will prevent the valve from exceeding maximum
ow, cavitating, or causing other damage to valve or system
from high water velocities.
2. For making adjustments and servicing allow for adequate space
around the valve before installing valve.
3. When installing a ZW204, gate valves installed on both inlet and
outlet are recommended for maintenance allowing for isolation of
valve.
4. Position the main valve in line matching the direction of ow as
indicated on the valve model tag with the proper direction of ow
in the system. Once attached to line, double check all fasteners/
bolts in the pilot system and on main valve are tight and there is
no damage prior to pressurizing system.
NOTE: Pressure in some applications can be very high so be
thorough in checking and inspecting for proper installation
and makeup.
NOTE: Upstream pressure should be at least 10 psi greater
than downstream hydrostatic pressure when valve is
closed.
5. The oat ball and rod assembly must be mounted in the verti-
cal position above the water in a tank or reservoir.
Note: A stilling well is required to surround the oat in
tanks or reservoirs which are subject to waves of any kind.
Verify oat has adequate clearance to move freely in all
oat positions.
6. Go to step 7 if installing a ZW204 with valve mounted pilot.
When installing a ZW204 with remote pilot, route tubing from
the main valve to the oat valve according to the schematic dia-
grams on page 3. Port P on the oat valve should be connected
Installation / Start-up
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7. Float rod, oat, stop collars and counterweight must be
installed on site for specic application.
8. Assemble the oat rod assembly without the oat for initial
setup. Assemble the parts in the order shown on the oat rod
assembly diagram. A standard oat rod assembly consists of
two 1 ft. long rods, two bolts, a lock washer, two stop collars
with setscrews, and an extension rod setscrew.
9. With the pivot arms horizontal, set the upper stop collar 3
inches above the desired high water level and set the lower
stop collar 3 inches below the desired low water level.
Note: The distance between the stop collars should not
exceed 40 inches or natural bouyancy of the rod will effect
stop points.
10. Install counterweight on the counterweight pivot rod with
the counterweight setscrew installed in the counterweight.
11. Adjust the counterweight position until the counterweight
rod is balanced horizontally.
Note: Because of buoyant forces pushing up on the oat
rod when it is submerged in water, small adjustments must
be made to the position of the counterweight to correctly
balance the oat valve.
12. Once the counterweight balances the oat rod, make
small adjustments to the position of the counterweight so the
valve pivot rods are horizontal when the water level is halfway
between the stop collars(the bottom of the oat rod will be sub-
merged). Once completed, tighten the counterweight setscrew
and install the oat.
Note: If installing additional oat rods (more than 2 feet),
2 counterweights must be installed on the counterweight
pivot rod. The maximum total length of the oat rod is 5
feet.
13. After pilot system has been adjusted and the oat valve is
properly operating the main valve, opening and closing speed
controls (O or L) can be adjusted as needed.
14. When setting speed controls, turning the adjustment screw
into the speed control will restrict the amount of ow through
the needle valve. Depending on whether the control is for
opening or closing (refer to ZW204 schematic) the control will
either slow the opening or closing of the main valve when the
adjustment screw is turned into the speed control. Adjust as
needed and tighten jam nut. In general a closing speed control
on a ZW204 should be at least 3 turns out from the furthest
closed position to prevent high tank overow.
CAUTION: Depending on inlet pressures and ow rates
through the main valve, closing times could be longer than
anticipated. Verify water level is well below the top of the
tank or reservoir when the main valve closes or adjust the
upper stop collar on the oat rod so the main valve starts
to close at a lower water level to prevent overow.
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5
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PARTS LIST
ITEM DESCRIPTION
1, 13 ROD END BOLT SS
2 5/16 LOCK WASHER SS
3 FLOAT ROD BRACKET
4, 10 STOP COLLAR
5, 11 STOP COLLAR SET SCREW SS
6, 9 FLOAT ROD SS
7 EXTENSION ROD SET SCREW SS
8 6" FLOAT SS
12 BOTTOM ROD WASHER

Troubleshooting
When performing troubleshooting and diagnosis checks it is recommended that the following steps be performed in sequential order
for best results.
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dicator (model ZPI) is closed. If the main valve does not close
and the pilot is operating correctly go to the “Diaphragm Check”
and “Diaphragm Movement Check” sections.
4. If there is continuous ow (even a trickle) from the outlet of
the main valve when the oat pilot is in an “up” position, the
main valve is not sealing properly or the pilot is not setup cor-
rectly.
• Verify the pilot is connected according to the schematic
diagram and correct if necessary.
• If the oat pilot is connected correctly, go to “Diaphragm
Check” and “Diaphragm Movement Check” sections to
determine whether those items are operating correctly.
• If the “Diaphragm Check” and “Diaphragm Movement
Check” do not show apparent issues, the main valve is
leaking and is allowing pressure to creep by the valve
seal. It is recommended that the valve be disassembled
and inspected (refer to “Disassembly” section).
5. If the main valve closes and no ow is coming from the outlet
of the main valve, slowly close the inlet isolation valve on the
main valve. With the main valve closed, slowly re-open the
cover isolation valve. Move the oat to the “down” position. This
will cause the valve to open and water to ow. If the main valve
is not owing water, check for the following:
• Water should discharge from the E port on the oat pilot.
If water does not discharge from E, verify the pilot is con-
nected to the main valve correctly and that there is pres-
sure on the inlet of the main valve.
• Otherwise, if water does not ow from the outlet, the main
valve is not opening. It is recommended that the valve be
disassembled and inspected (refer to “Disassembly”
section).
DIAGNOSIS CHECKS
CAUTION: Do not service valve while under pressure.
When performing diagnosis checks on the ZW204 and the
valve is fully open, high ow rates and high downstream
pressures can occur. In order to prevent harm to person-
nel, equipment and downstream piping be sure that there
are no blocked valves in the system before performing
checks.
1. To verify if the non-modulating oat pilot is properly operat-
ing, close the cover isolation valve on the main valve. Verify
there is pressure on the inlet of the main valve. Raise and lower
the oat several times through the oat’s entire travel. A small
amount of water should come out of port E only when the oat
is moved from the “up” position to the “down” position.
2. The oat pilot is not operating correctly if:
• Water does not come out of port E. Check for inlet
pressure to the main valve and pressure at port P on
the oat pilot. If there is pressure, then it is recom-
mended that the oat valve be disassembled and
inspected. (Refer to PV-FNM “Disassembly” section.)
• Water ows out of port E when the oat is in an “up” posi-
tion. Make sure port P is connected to the inlet of the
main valve otherwise, it is recommended that the oat
valve be disassembled and inspected. (Refer to PV-FNM
“Disassembly” section.)
• There is a continuous stream of water from port E. It is
recommended that the oat valve be disassembled and
inspected. (Refer to PV-FNM “Disassembly” section.)
If the oat pilot is operating correctly proceed to the next step.
3. Open the cover isolation valve on the main valve. Slowly
raise the oat to the “up” position to allow the cover to ll and
the main valve to close. If installed, verify the valve position in-
ZW204 SCHEMATIC
STANDARD COMPONENTS OPTIONAL FEATURES
1 Main Valve C 40XL Hydraulic Check w/
2 850MXL Isolation Valve Isolation Valve
3 SXL Wye Type Strainer L SC1 Closing Speed Control
4 On/Off Float Valve PV-FNM O SC1 Opening Speed Control
5 3-Way ACL Pilot Z ZPI Valve Position Indicator
W Independent Oper. Pressure
USE FOR SIZES: 1 1/4" - 6" USE FOR SIZES: 8" - 10"
FLOW
W
2
2
1
2
C
Z
C
3
4O
FLOW
W
2
1
2
2
2
C
O
Z
L
5
4
3
C

DIAPHRAGM CHECK
1. Slowly close upstream shut off valve and relieve all pressure
downstream.
2. With all pressure relieved in the main valve, close both inlet
and cover isolation valves and remove side plug on cover and
leave off.
3. Then open upstream shut off valve partially, allowing water to
ow through the valve. While owing water, monitor the open-
ing on the cover. Water will come out of the cover as the ACV
opens. Once the valve opens fully subsequent water should
not come out of the cover. If water ows continuously through
the open hole in the cover, then there is likely damage to the
diaphragm or uid is leaking past the diaphragm assembly
due to loose assembly. It is recommended that the valve cover
be removed to investigate the leakage (to remove cover see
"Maintenance" section for procedures). If no water ows out of
the cover then the diaphragm is good and you may proceed to
the diaphragm movement check.
DIAPHRAGM MOVEMENT CHECK
1. The diaphragm movement check can be determined during
the diaphragm check or it can also be performed with the use of
a valve position indicator model ZPI.
2. Replace cover plug and open pilot ball valves on inlet and
cover.
3. Moving the oat position to the "up" position will direct the
ow to the cover causing it to close. NOTE: Slow or delayed
closing of main valve is normal and is due to the time required
to ll, pressurize cover and stretch the diaphragm into the
closed position. This normal delay is not mechanical binding of
the valve assembly.
4. Using the valve position indicator, make note of the closed
position on the indicator. Compare distance of the open mark to
the close mark and compare to Table 3.
5. Verify that the main valve is closed, by opening a down-
stream source (not the outlet isolation ball valve on the main
body). If water continuously ows, then the main valve is not
sealing properly. Double check the valve movement matches
the valves in Table. 3 and refer to the disassembly procedures
section if it does not. This is an indication that the main valve
is not sealing due to an obstruction between the seat and the
seal or a damaged seal. If water does stop owing and the
measured valve movement does not match Table. 3, then there
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is possible damage under the cover. Remove cover to identify
obstruction and replace parts as necessary.
6. For smaller valves (6” and below) diaphragm checks can be
performed by hand with the use of a valve stem tool. The valve
stem tool can be made using Table 4 to create a “T” bar handle
with the appropriate threads on the opposite end of the “T” handle.
7. To perform the diaphragm check using the valve stem tool,
rst remove all pressure in the system and vent the cover.
Then remove the center plug on the cover and insert tool into
the top of the stem threads. Once the tool is inserted, the
valve can be lifted up and the valve movement can be mea-
sured by creating marks on the tool in the opened and closed
positions. The distance between marks is the valve stem
travel. Replace or repair any parts as necessary.
PROBLEM POSSIBLE CAUSES CORRECTIVE ACTION
1. Main Valve fails to open 1. No pressure at valve Inlet 1. Check Inlet pressure
2. Main valve diaphragm assembly inoperative 2. Disassemble, clean, and polish stem, replace defective parts
3. Float pilot connected to incorrect ports 3. Check ports and connect according to schematic
4. Float is stuck up 4. See pilot system troubleshooting
2. Main Valve fails to close 1. Foreign matter between disc and seat or worn 1. Disassemble the main valve, remove debris, clean parts, and
disc replaced defective parts
2. Scale on stem or diaphragm ruptured 2. Clean parts, and replace defective parts
3. No pressure going to main valve cover port
1) Float pilot mounted too high above main valve 1) Mount oat pilot lower or increase inlet pressure
2) Clogged wye strainer 2) Remove, clean, and/or replace
4. 38-850XL(ball valves) closed 4. Open ball valves
5. Float is stuck down 5. See pilot system troubleshooting
TABLE 2. MAIN VALVE TROUBLESHOOTING
PROBLEM POSSIBLE CAUSES CORRECTIVE ACTION
1. Pilot continuously dumps water
through discharge port
1. Main valve diaphragm damaged 1. Replace diaphragm
2. Loose main valve stem 2. Tighten main valve stem nut
3. Damaged pilot 3. Replace any damaged components of pilot assembly.
2. Float is stuck (stays in up or 1. Stuck oat valve pivots 1. Ensure all pivots points are free to move
down position) 2. Worn or damaged oat valve 2. Disassemble and replace damaged components of valve
TABLE 1. PILOT SYSTEM TROUBLESHOOTING
VALVE SIZE (in) THREAD SIZE UNF INTERNAL
1-1/4" - 1-1/2" 10-32
2" 10 - 32
2-1/2" 10 - 32
3" 1/4 - 20
4" 1/4 - 20
6" 1/4 - 20
8" 3/8 -16
10" 3/8-16
TABLE 4. VALVE STEM THREAD SIZE
TABLE 3. VALVE STEM TRAVEL
VALVE SIZE
(in)
VALVE SIZE
(mm)
STEM TRAVEL
(in)
STEM TRAVEL
(mm)
1-1/4" - 1-1/2" 38 0.4 10.2
2" 50 0.7 18.0
2-1/2" 65 0.8 21.3
3" 80 0.9 23.4
4" 100 1.1 28.8
6" 150 1.7 43.4
8" 200 2.4 59.7
10" 250 2.8 71.1

Maintenance Instructions
PREVENTATIVE MAINTENANCE
The Zurn Wilkins ZW200 models require minimal maintenance.
However, it is highly recommended to schedule annual inspec-
tions and to have a repair kit on hand before work begins.
DISASSEMBLY
Warning: Because of the ability to perform inspections and
maintenance without removal from the system, it is very
important that all shut off valves be closed and all pressure
relieved in the valve before beginning disassembly. Failure
to do so can result in personnel injury or equipment damage.
1. Verify that all pressure sources are closed up and down-
stream of valve.
2. Remove pressure in pilot system by loosening the tube t-
tings to the valve body and cover. When all pressure has been
vented, continue to disassemble the pilot control valve and
cover tubing. NOTE: Taking a picture before tear down can help
with re-assembly of pilot system.
3. Next remove the cover by loosening and removing the
cover bolts. If the cover does not come off easily it may be
necessary to loosen the cover using a brass chisel and rubber
mallet. Apply the chisel under the cover pointing upward away
from valve body and tap bottom of cover with the chisel and
mallet to loosen the cover. Once the cover is loose, pull cover
straight up to avoid damaging the stem and stem bearing in
the cover. On larger valves 8” and up, eye bolts and a hoist are
recommended due to the weight of these larger covers.
4. With the cover removed, the diaphragm assembly can be
removed. To avoid damaging the seat bushing, grab the stem
and lift straight up. For larger valves 8” and up it is recom-
mended that an eye bolt with the proper stem threads be used
with a hoist to lift the assembly out of the valve (see Table 4 for
appropriate stem threads).
5. Next it is recommended that the diaphragm assembly be
placed in a vise with the bottom hex nut secured. Once secured
remove the spring and stem nut. While removing the nut in-
spect the stem threads. Clean stem with a wire brush if mineral
deposits or corrosion are present.
6. After inspecting the stem and removing the nut the dia-
phragm assembly can be dismantled. If the valve has not been
serviced in awhile it is possible that the assembly will require
the use of a rubber mallet or pry bars to dismantle the assem-
bly. If this is the case gently tap or pry the components until the
components are free to move. When disassembling be sure to
clean, inspect, and save all components. Replace any dam-
aged components as necessary.
7. The last component to inspect is the seat which is in the
body of the main valve. During inspection of the seat, clean and
polish as necessary with ne grit wet/dry sandpaper (400 grit or
higher). Typically, if after cleaning there is no visual damage or
excessive wear the seat should not require removal. If damage
is present or the seat is excessively worn the seat should be
replaced.
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8. To remove the seat, on valves 6” and smaller the seat is
threaded into the body and will require a seat removal tool. Care
should be taken when removing the seat to avoid damaging.
On 8” and larger valves, the seat is held in place with at head
hex screws. For larger valves a seat puller may be required to
remove the seat from the body.
INSPECTION OF COMPONENTS
Cleaning of components is required for proper inspection. Lime
deposits are common in systems that use water. To remove
deposits, ne grit wet/dry sandpaper (400 grit or higher) can be
used. If deposits cannot be removed, off the shelf lime deposit
remover can be used. Prepare a solution following the lime
deposit remover instructions and soak components (excluding
rubber components) until lime deposits are removed.
CAUTION: When handling chemicals (acids) be sure to use
proper safety equipment (gloves and eye protection) and prac-
tices. After soaking components, be sure to thoroughly rinse
all components before handling and re-assembling valve.
Once all valve components have been cleaned, inspect each
component looking for damage, abnormal wear & corrosion,
and replace all components that look questionable. Replace all
rubber components including the diaphragm, o-rings and disc
each time the valve is serviced or inspected (rubber compo-
nents are standard in ZW200 repair kits.

REASSEMBLY
1. First reinstall seat into body. Be sure to use lube around
seat o-ring before tightening. Tighten seat according to torque
values in Table 5 using seat tool.
2. Next place valve stem in a vise clamping on the hex portion
of the stem. Then assemble the diaphragm assembly as
shown in Figure. When assembling be sure that the diaphragm
is centered on the raised step of the disc retainer. It is also
recommended to apply lube to stem threads and o-rings before
tightening. Then tighten the stem nut according to Table 5 for
torque values.
3. Lower diaphragm assembly carefully into the seat bushing
Be careful not to damage the seat or stem while installing as-
sembly. Rotate the assembly as needed until the bolt holes on
the diaphragm line up with the body bolt holes.
4. Place lower spring disc on the diaphragm disc and place
spring on top of the assembly. Then install cover, aligning
the bolt holes and insuring that the cover is not pinching the
diaphragm between the bolt holes. Position cover so plug holes
are in original position.
5. Install cover bolts and tighten in a star pattern to the torque
values in Table 5.
6. Before installing center cover plug manually check that
assembly has full operating travel before installing the pilot
assembly (refer to “Diaphragm Movement” in the diagnosis
checks section).
7. Once full operation range of the main valve is veried,
begin reinstalling pilot system.
8. After installing pilot system double check that all plugs,
bolts, and ttings are sealed and tight before applying pressure.
9. Slowly open upstream isolation valve to pressurize the
system and check for any leaks.
10. Stop leaks as needed and proceed to “Start-Up” and “Di-
agnosis Check” sections for returning valve to proper system
operations.
VALVE
SIZE
(in)
COVER
(ft-lbs)
DIAPHRAGM
ASSEMBLY
(ft-lbs)
THREADED
SEAT
(ft-lbs)
SEAT
BOLTS
(ft-lbs)
1-1/4" 3.5 7.5 11 N/A
1-1/2" 3.5 7.5 11 N/A
2" 15 20-25 30 N/A
2-1/2" 25 25-35 60 N/A
3" 25 35-45 70 N/A
4" 55 40-50 85 N/A
6" 110 50-60 95 N/A
8" 120 60-70 N/A 7.4
10" 184 70-75 N/A 7.4
TABLE 5. VALVE TORQUE SETTINGS
COVER CENTER PLUG
COVER BOLTS
COVER NUTS (8" AND LARGER)
COVER PLUG
COVER
COVER BEARING (STEM GUIDE)
UPPER SPRING DISC (4" AND LARGER) * †
SPRING †
LOWER SPRING DISC (4" AND LARGER) * †
STEM NUT
STEM WASHER
DIAPHRAGM WASHER
(DIAPHRAGM DISC)
DIAPHRAGM*
UPPER STEM O-RING*
DISC RETAINER
(PLUNGER)
LOWER STEM O-RING*
DISC (SEAL RING)*
DISC GUIDE
(SEAL RING RETAINER)
STEM
SEAT SCREWS (8" AND LARGER) ‡
SEAT ‡
COVER STUDS (8" AND LARGER)
SEAT O-RING ‡
BODY
BODY PLUGS
STEM ASSEMBLY †
* RUBBER REPAIR KIT ITEMS
† COMPLETE REPAIR KIT ITEMS
‡ SEAT REPAIR KIT
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Maintenance (PV-FNM Valve)
MAINTENANCE (PV-FNM VALVE)
The Non-Modulating Float Pilot must be installed in a vertical
position with a stilling well surrounding the oat if the tank or
reservoir is subject to waves of any kind. Port P on the oat
valve should be connected to the inlet of the main valve. Port A
should be connected to either the main valve cover or accelera-
tor pilot cover if installing an 8 or 10 inch valve.
DISASSEMBLY
Prior to disassembly, relieve all pressure in pilot system and
then remove the PV-FNM. Note the pilot connections and
reinstall the pilot with the same connection placement when
nished with maintenance.
1. Remove the oat rod assembly by taking out the two cotter
pins from the oat rod bracket and parallel pivot rods.
2. Remove the counterweight and counterweight assembly if
desired. This is not necessary for performing maintenance to
the oat valve.
NOTE: If removing counterweight, note the postion so it
can be reinstalled easily.
3. Remove the four screws and four nuts from the valve body
with a screwdriver and small adjustable wrench.
4. Lift the cover assembly straight up off of the valve body.
NOTE: Do not drop the cover o-ring, valve seat and spring,
which are not attached to the end of the stem. Be careful not
to scratch or damage the polished surfaces of the valve
body or valve seat.
5. Carefully remove the valve seat and spring. Carefully wipe
the lapped surface of the valve seat and valve body.
6. Remove the o-ring on the bottom of the cover.
7. Next use a small screwdriver to remove the screw from the
valve stem and pivot rod.
8. Once the stem screw is removed slide the valve stem out of
the cover along with a washer and small o-ring.
9. After complete disassembly, thoroughly clean and inspect all
components before reassembly. Replace any parts as neces-
sary after inspection.
PV-FNM VALVE
REASSEMBLY
Reassembly of the PV-FNM is the reverse of disassembly.
1. Place the valve body on top of the valve base bracket with
the polished surface up. Line up all four screw holes in the
valve body and base plate. There is only one orientation in
which all four holes line up together.
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2. Place a dab of grease on the inner polished surface of
the valve body. Carefully place the valve seat, with polished
surface down, onto the center of the valve base. Make sure the
valve seat is oriented as shown below with the slot in the top of
the valve seat parallel to the bottom of the base plate.
3. Next place the spring on top of the valve seat followed by the
valve stem. The roll pin in the valve stem will slide into the top
slot of the valve seat.
4. Place the washer then the small o-ring on the valve stem.
5. Insert an o-ring into the slot on the bottom of the cover. Take
the valve cover and position the “P” on the cover to the right
side. Line up the screw holes and the stem hole then slide the
cover partially on to the stem.
6. Take the valve pivot rod and place into the top slot in the
cover with the rod out to the left. Line up the through hole in the
valve pivot rod with the center holes in the cover.
7. Slide the valve pivot rod down on to the stem as the cover is
pressed onto the valve body. Hold the cover down and do not
release.
8. Insert the four valve
screws and thread into
valve nuts. Tighten all of the
screws. Now the cover can
be released.
9. Next line up the stem
screw hole with the hole on
the end of the valve pivot
rod. Insert the set screw and
tighten.
10. Reinstall the counter-
weight and counterweight
assembly if disassembled.
11. Reinstall the oat assembly by inserting the two cotter pins
into the oat rod bracket and parallel pivot rods.
12. Reinstall into the pilot system once maintenance is com-
pleted. For further assistance or ordering replacement parts go
to www.zurn.com or call product support 877-222-5356
Valve Seat. Position seat exaclty as shown.
Note position of the milled slot on
bottom
(dash lines) of the seat.

A
A
SECTION A-A
4
7
8
9
56
47
2
1
1
5
3
19
14
12
13
15
23 22 21 20 18 17 16
26
25
24
28 29
27
30 31
32
14
10
11
3
19
12
ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:[phone] Fax:[phone]
®
www.zurn.com
PARTS LIST
ITEM DESCRIPTION
1 SS COTTER PIN
2 FLOAT ROD BRACKET
3 VALVE PIVOT ROD
4 STOP COLLAR
5 ROD END BOLT SS
6 BOTTOM ROD WASHER
7 STOP COLLAR SET SCREW SS
8 6" FLOAT SS
9 FLOAT ROD SS
10 EXTENSION ROD SET SCREW SS
11 5/16 LOCK WASHER SS
12 VALVE COVER
13 VALVE STEM
14 VALVE SCREW SS
15 1/8" BRASS PLUG
16 COUNTERWEIGHT PIVOT ROD
17 COUNTERWEIGHT SET SCREW SS
18 COUNTERWEIGHT
19 BASE BRACKET
20 CONE POINT SET SCREW SS
21 COUNTERWEIGHT BRACKET SCREW SS
22 COUNTERWEIGHT STEM
23 COUNTERWEIGHT BRACKET
24 VALVE SEAT
25 ROLL PIN SS
26 VALVE STEM SCREW
27 VALVE STEM O-RING
28 VALVE STEM WASHER SS
29 VALVE SPRING
30 VALVE COVER O-RING
31 VALVE BODY
32 VALVE NUT SS

ISZW204 (REV. 7/13)
FLOW CHARACTERISTICS
ZURN WILKINS
1747 Commerce Way, Paso Robles, CA 93446 Phone:[phone] Fax:[phone]
®
www.zurn.com
Note: If the valve is to be used for continuous ow, supply adequate back pressure to operate the valve below
the "Damage Zone" shown on the "Pressure Reduction Limit" chart. If the valve discharges to atmosphere
adequate back pressure is very important, contact Zurn Wilkins for assistance.
0
1
10
100
10 100 1000 10000
PRESSURE DROP (PSI)
FLOW (GPM)
BODY MINIMUM FRICT ION LOSS
PRESSURE REDUCTION LIMIT
0
50
100
150
200
250
300
020 40 60 80 100 120
OUTLET PRESSURE (PSI)
INLET PRESSURE (PSI)
3" 4" 6"
Safe
operating zone
Noise
zone
Damage Zone Noise Limit
1 1/4" 1 1/2" 8" 10"
2 1/2"
Cavitation damage
zone (intermittent
operation allowed)
2"