Val-Matic 2-42 Flanged Vacuum Breaker - Manual (Page 7)

6
WARNING: The line must be drained before
removing the valve or pressure
may be released causing injury.
TROUBLESHOOTING
Several problems and solutions are presented below
to assist you in trouble shooting the valve assembly
in an efficient manner.
• Valve Chatters or Vibrates: Check to see if the
pipeline operates at a regular vacuum condition.
Contact the factory about alternate spring settings.
• Valve Leakage: Check gaskets and flange bolts
for tightness. Drain line, remove valve, and
inspect seating surfaces for debris or damage. If
rubber seat (2) is damaged, then a new seat
should be installed.
• Valve Does Not Pass Flow: Verify that seat end is
up away from the pipeline or tank. Verify that
pipeline is at a vacuum condition greater than
minus 0.25 psig. Verify that isolation valve is
open and there is no line blockage downstream.
• Valve Slams: Remove valve and inspect spring.
Heavier springs can be furnished for severe high-
head applications.
DISASSEMBLY
The valve should be removed from the pipeline for
disassembly. All work on the valve should be
performed by a skilled mechanic with proper tools.
Refer to Figure 4.
1. Lay valve on flat surface or bench with the hood
facing up. 12” and larger valves require support
for the spring during disassembly.
2. Remove ring plate (10) by removing bolts and nuts
(11).
3.
Remove seat retaining screws (6). Note: 2-1/2”
valves have threaded seats in lieu of retaining
screws.
4.Flip the seat (2) over and inspect the seating
surface. Some minor dents and discoloration are
normal. Grooves or wear areas will cause leakage
and requires seat replacement. Note: Replace
seat if resilient seat is worn or damaged.
5. Lift disc (3) from body. Inspect shafts and seating
surfaces for wear. The shaft diameter is normally
about 1/32” smaller in diameter than the hole in
the seat (2) and bushing (5). Some minor dents
and discoloration are normal. Wear areas will
cause leakage and require seat replacement.
Heavy mineral deposits should be removed with
lapping compound or fine sand paper.
6. Remove spring (4) and check for wear or cracks.
7. Remove bushing (5) and inspect for wear. The
inside diameter of the bushing should be about
1/32” larger in diameter than the shaft.
REASSEMBLY
All parts must be clean and gasket surfaces should
be cleaned with a stiff wire brush in the direction of
the serrations or machine marks. Worn parts,
gaskets, and seals should be replaced during
reassembly.
1. Insert bushing (5) into body (1). The bushing is
retained by the spring (4).
2. Lay spring (4) and disc (3) over bushing (5).
3. Install seat (2) with the retaining screws (6). 12”
and larger valves may require a 2x4 board and C-
clamps to compress the spring into the body.
4.Install ring plate (10) with bolts and nuts (11) and
new gasket (8).
5.Install new gaskets and valve. Tighten flange bolts
evenly using the cross-over tightening method and
the torque values given in Table 1 on page 2.
PARTS AND SERVICE
Parts and service are available from your local
representative or the factory. Make note of the
Valve Size and Model Number located on the valve
nameplate and contact:
Val-Matic Valve and Manufacturing Corp.
905 Riverside Drive
Elmhurst, IL 60126
Phone: (630) 941-7600
Fax: (630) 941-8042
www.valmatic.com
A sales representative will quote prices for parts or
arrange for service as needed.