Wilkins Zurn Service Procedures

1
Wilkins / ZurnService Procedures

• Models
• 350, 350A, 350DA
• 450, 450DA
• 375, 375A, 375DA
• 475, 475DA
• 950, 950XL, 950DA
• 975, 975XL, 975DA

2
Contents

• Model
• 350 ¾-1
• 375 ¾-1
• 350(A), 350DA 21/2-10
• 375(A), 375DA 21/2-10
• 450, 450DA 21/2-10
• 475, 475DA 21/2-10
• 950, 950XL ¾-2
• 975, 975XL ¾-2
• 950, 950DA 21/2-10
• 975, 975DA 21/2-10

• Page
• 2
• 6
• 14
• 14
• 14
• 14
• 24
• 24
• 31
• 31

3
350¾-1
4
Check Housing Removal

• The plastic housing (vessel) must be removed for
  service.
• There is no spring load.
• Housing is bolted and o-ring sealed.
• Remove the four housing bolts.
• Locate the notch between housing and body and pry
  loose with a screwdriver.

5
Check Valve Removal

• Check valve modules.
• Modules are located inside the housing.
• Modules are sealed by o-rings.
• Both modules slide toward the outlet of the
  housing.

6
Disassemble Check Module

• Modules are spring loaded.
• Locate the notch between the seat and tailpiece
  of each check.
• Holding the module firmly, twist and snap apart
  with a screwdriver.

7
Check Seat Removal

• The check seat is free once the module has been
  disassembled.
• The seat is part of the module.
• If seat is damaged, the entire module must be
  replaced.

8
Check Disc Replacement

• The check disc and poppet are free once the
  module has been disassembled.
• The disc and poppet must be replaced as one
  component.

9
Check Valve Reassembly Notes

• Reassemble in reverse order.
• Lubricate o-rings on check modules and slide back
  into housing.
• Make sure checks are in the correct order and
  facing the correct direction.

10
Housing Reassembly Notes

• Lubricate the inlet and outlet o-ring on the
  housing.
• When installing housing, match slight taper on
  the outlet of the housing with the taper in the
  body.

11
375¾-1
12
Housing Removal

• The plastic housing (vessel) must be removed for
  service.
• There is no spring load.
• Housing is held in place by a wedge and o-ring
  sealed on both ends.
• Remove wedge screws.

13
Housing Removal

• Pull wedge straight out.
• Inserting a screw in center hole can help
  remove stuck wedge.
• Slide housing towards inlet and lift upward.

14
Check Valve Removal

• Check valve modules.
• Modules are located inside the housing.
• Modules are sealed by o-rings.
• Both modules slide out of the body inlet.

15
Disassemble Check Module

• Modules are spring loaded.
• Holding firmly, twist spring retainer counter
  clockwise.

16
Check Seat Removal

• Check seat is free once the module has been
  disassembled.
• The seat is part of the module.
• If the seat is damaged, the entire module must be
  replaced.

17
Check Disc Replacement

• Remove screw, disc retainer, and disc.
• Reassemble module in reverse order.

18
Check Valve Reassembly Notes

• Lubricate o-rings on modules.
• Drop 2 module in body. Then drop 1 module in
  and turn until 1 spring retainer lines up with
  2 seat.
• Push both modules into housing.

19
RV Cover Removal

• RV cover is sealed by the diaphragm.
• There is a slight spring load on cover.
• Hold cover firmly while removing screws.

20
RV Stem Removal

• Gently pull the RV stem out of the housing.
• Spring is free once the stem is removed.

21
RV Seat Removal

• RV seat is o-ring sealed.
• Pull seat straight out of housing.

22
Disassemble RV Stem

• Remove RV retaining screw.
• Pull plunger and disc holder apart.

23
RV Rubber Replacement

• The RV disc and diaphragm are free once the stem
  has been disassembled.
• Reassemble in reverse order.

24
RV Reassembly Notes

• Lubricate plunger o-ring on stem.
• Insert RV stem into cover.
• Place spring in position over seat.
• Make sure sensing o-ring is in position.
• Insert cover and stem into housing.

25
Housing Replacement Notes

• Lubricate o-rings on inlet and outlet of housing.
• Place housing between struts.
• Slide retaining sleeve downstream against
  housing.
• Replace wedge and wedge screws.

26
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27
350(A), 350DA, 450, 450DA375(A), 375DA, 475,
475DA21/2-10
28
Modification Overview

• The A suffix after the model number indicates
  that the inlet and outlet of the device body are
  grooved.
• The shut off valves are attached to the body with
  grooved couplers.

29
Single Access Cover Removal

• Cover is secured by a grooved coupling.
• Cover has no spring load.

30
Check Valve Removal

• Check valve module.
• 21/2-6 checks are secured by retainers and
  o-ring sealed.
• 8-10 checked are bolted into body and o-ring
  sealed.
• 1 check must be removed before 2 can be removed

31
Check Valve Removal 21/2-6

• Plastic Retainer There is one retainer securing
  the 1 check module.
• Pinch together the exposed ends, push down, and
  then pull downstream.

32
Check Valve Removal 21/2-6

• Wire Retainer There are two separate spring
  loaded plate retainers that secure the 2 check
  module.
• Pinch the sides of the spring together and
  rotate the plates out of the body groove, one at
  a time.

33
Check Valve Removal 21/2-6

• Once the retainer is removed the check module can
  be pulled straight out of the body.

34
Check Valve Removal 8-10

• 1 check Remove the 4 nuts and washers.
• 2 check Remove the 7 nuts, washers and the
  check retaining ring.

35
Check Disc Replacement

• 21/2-3- Remove the nut, washer, o-ring on back
  of module.
• 4-10 Remove the bolts, washers, and o-rings
  on the back of the module.
• Do not remove any hardware from the spring
  side of module.
• Separate the disc retainer from the module.

36
Check Seat Removal

• The check seat is part of the check module and
  can not be removed.
• If the seat is damaged, the complete check module
  will need to be replaced.

37
Check Valve Reassembly Notes

• Make sure the rollers on the check module are
  positioned at 300 and 900.
• Install the check module into the body and close
  the test cock to hold check in place.

38
Check Valve Reassembly Notes

• Plastic Retainer -
• Install the plastic retainer by inserting one end
  into the body groove and then sliding your hand
  around the face of the retainer pushing it into
  the groove as you go.
• The retainer will snap into place when it is
  fully seated.

39
Check Valve Reassembly Notes

• Wire Retainers -
• Retainers are positioned at 1200 and 600.
• Install each retainer into the body groove one
  plate at a time.
• Squeeze the spring ends together to clear the
  stops on the face of the seat.

40
RV Cover Removal

• Cover is sealed by the diaphragm.
• Remove sensing line.
• Cover has a slight spring load.
• Hold cover firmly as the bolts are removed.

41
RV Stem Removal

• Gently pull on diaphragm to remove the RV stem.
• The spring should fall out when the stem is
  removed.

42
RV Seat Removal

• The seat is pushed into the body and o-ring
  sealed.
• Simply pull the seat straight out of the body.

43
RV Stem Disassembly

• Remove the retaining bolt and pull apart.

44
RV Rubber Replacement

• The diaphragm and seat disc are free once the RV
  stem has been disassembled.
• The bead and cup of the diaphragm should face
  toward the bolt end of the stem.
• Reassemble stem in reverse order.

45
RV Reassembly Notes

• Form the diaphragm to lay flat against the RV
  cover.
• The bead on the diaphragm will line up with the
  groove on the RV body.
• Replace and lubricate the plunger o-ring.

46
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47
950, 950XL 975, 975XL¾-2
48
Modification Overview

• The 950 / 975 (original version)- had no
  replaceable check seats and buna-n check discs.
• The 950A / 975A- had bronze replaceable seats.
• The 950XL / 975XL- have plastic replaceable seats
  and silicone check discs.
• The 950XLT- is a top entry body style.

49
Check Cover Removal

• Cover is threaded into body and o-ring sealed.
• Cover is spring loaded.
• Loosen cover with wrench, then remove by hand
  while holding tightly against spring pressure.

50
Check Valve Removal

• Poppet style check valve.
• The poppet and spring are free once the cover is
  removed.

51
Check Seat Removal

• Check seats are threaded into body and o-ring
  sealed.
• A special tool is needed for removal.

52
Check Disc Replacement

• Remove screw and disc washer from poppet.
• Reassemble in reverse order.

53
Check Valve Reassembly Notes

• Inspect and clean the guide bore on the cover.
• The stem must move freely in the guide bore.
• Reassemble in reverse order.

54
RV Cover Removal

• Cover is sealed by the diaphragm.
• Cover has a slight spring load.
• Hold cover firmly as the bolts are removed.

55
RV Stem Removal

• Gently pull on the diaphragm to remove the RV
  stem.
• The spring should fall out when the stem is
  removed.

56
RV Seat Removal

• The seat is threaded into body and o-ring sealed.
• A special tool is needed to remove the RV seat.

57
RV Stem Disassembly

• Remove the retaining screw.
• Pull the disc retainer and stem apart.

58
RV Rubber Replacement

• The diaphragm and seat disc are free once the
  stem is disassembled.
• Replace rubber in reverse order.
• Lubricate plunger o-ring on stem.

59
RV Reassembly Notes

• Reassemble the stem in reverse order.
• Position spring in body.
• Make sure diaphragm does not cover hole for
  sensing line.

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61
950, 950DA975, 975DA21/2-10
62
Modification Overview

• The 950 / 975 (21/2-10) were discontinued in
  2004.

63
Check Cover Removal

• Cover is o-ring sealed.
• Loosen bolts 1/2. The spring load is now
  released from the cover and retained by the check
  subassembly.
• Verify spring load before removing all the
  bolts.

64
Check Valve Removal

• Center stem guided check assembly.
• Disc spring subassembly.
• Slide subassembly straight out of seat and body.

65
Check Seat Removal

• Seats are bolted into the body and o-ring sealed.
• Remove the bolts and pull the seat straight out
  of the body.
• 4-10 - Inspect plastic guide bushing in center
  of seat.

66
Check Disc Replacement

• Remove retaining nut and disc retainer.

67
Check Valve Reassembly Notes

• Reassemble checks in reverse order.
• Lubricate o-rings.

68
RV Cover Removal

• Cover is sealed by the diaphragm.
• There is no spring load on cover.
• Remove bolts.

69
RV Module Removal

• Module is o-ring sealed.
• Pull the module straight out of body.

70
RV Seat Removal

• 21/2-6 RV seat is bolted into body and o-ring
  sealed.
• Remove the allen screws and pull seat straight
  out of body.
• 8-10 RV seat is threaded and o-ring sealed.

71
Disassemble RV Module

• Module is spring loaded.
• Holding the module firmly, remove the stem bolt.

72
Disassemble RV Module

• Remove the guide bushing from the stem.

73
RV Disc Replacement

• Remove retaining bolt, disc washer, and disc.
• Reassemble in reverse order.

74
RV Reassembly Notes

• Bead on the edge of the diaphragm should face the
  disc end of the module.
• Lubricate o-rings.
• Push the module straight into the body.
• Diaphragm bead will line up with the groove on
  the RV body.
• Check the sensing line o-ring on the cover.

75
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