EFD 741V MAINTENANCE GUIDE

741V

MAINTENANCE & PARTS GUIDE

IMPORTANT!

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Supervisors

For EFD sales and service in over 30 countries,
contact EFD or go to www.efd-inc.com/contact

EFD, Inc.

East Providence, RI USA
800-556-3484; [phone] (outside the USA)
[e-mail] www.efd-inc.com

EFD International Inc.

Dunstable, Bedfordshire, UK
0800 585733 or [phone]
Ireland 00800 8272 9444
[e-mail] www.efd-inc.com

EFD, Inc., Asia

China: [phone]
[e-mail] www.efd-inc.com/cn
Singapore: [phone] [e-mail]

Electronic pdf files of EFD manuals are also available at
www.efd-inc.com/manuals.html.

A NORDSON COMPANY

O-ring

(Buna-N)

#7806

Retaining
washer
#7807

Packing spring
#7808

Needle packing assembly
#7810

O-ring (Buna-N)

#4049

Fluid inlet fitting
#7543BP for 1/4" OD tube
(installed)
#7610BP for 3/8" OD tube
(supplied)

Screws
HW6-32X1

Fluid body
#7430-SS (stainless

steel)

#7430 (hard-coated aluminum)

Tip adapter/
seat assembly
#7401

O-ring
(Viton)
#5148RV

SafetyLok

™

collar
#7403

2

3

4

7

16

17

Valve maintenance

To thoroughly clean fluid body and
replace needle packings:

1. Remove needle stroke control knob
and spring.

2. Remove inlet fitting and tip
adapter/seat assembly.

3. Remove fluid body from air cylinder
body, then remove O-ring.

4. Use extraction tool #7803 to remove
needle packings from fluid body.

5. Remove any remaining packings
and spring from needle.

6. Clean needle with cloth dampened
in solvent, and lubricate with Nye
Lubricant #865 included in the
Maintenance Kit.

7. Replace O-ring and reassemble
the valve in reverse order of
disassembly.

Note: Ensure that the lower cylinder
needle O-ring is back in place before
reinstalling the packing spring.

Replacing piston and needle
assembly or piston O-ring

8. Remove needle stroke control knob.

9. Remove piston return spring and
thrust washers.

10. Remove the snap ring.

11. With small pliers on the spring
pilot, pull the piston and needle
assembly out of air cylinder. The
piston and needle assembly is one
unit and cannot be disassembled.

12. Clean air cylinder body wall and
replace piston O-ring. Lubricate
with Nye Lubricant #865 included
in the Maintenance Kit.

Valve Disassembly and
Reassembly Procedures

CAUTION: To prevent damage, the valve
must be disassembled starting at the fluid
outlet end of the valve.

www.efd-inc.com [e-mail] USA 800-556-3484 Europe [phone] Asia [phone]

Sales and service of EFD®dispensing systems are available worldwide.

1

5 6

8

9

10

11

15

18

19 20 21

12

13. Reassemble the valve in reverse
order of disassembly.

14. Leak test the valve (see below).

Leak testing

15. Set the needle stroke control at
two turns open.

16. Shut off actuating air. Install an air
hose in the fluid inlet and connect
it to a 100 psi (7 bar) air supply.

17. Submerge tip adapter/seat
assembly in water. If air bubbles
appear, reseat the parts (see next
steps).

Reseating the needle and tip adapter
assembly

18. Disconnect all air to the valve.

19. Rotate the stroke adjustment knob
to the closed position.

20. To compress the needle into the
tip adapter, further rotate the stroke
adjustment clockwise one additional
reference mark.

21. Return stroke adjustment to normal
setting and cycle the valve. If a slight
leak remains, repeat steps 1 and 2.

22. If the leak persists, replace the tip
adapter.

Maintenance Kit

#741V-RK

Includes all O-rings, needle packing
assembly and lubricant.

Tools required:

6” Adjustable wrench

Snap-ring pliers

Packing extraction tool (#7803)

www.efd-inc.com [e-mail] USA 800-556-3484 Europe [phone] Asia [phone]

Sales and service of EFD®dispensing systems are available worldwide.

Air cylinder body
#7429 (aluminum)
#7429SS (stainless steel)

Air input hose
#78518A

Piston and needle
assembly #7805-SS

Snap ring
#7526

O-ring (Buna-N)
#7519

Needle stroke control
#7432 (aluminum)

O-ring (Buna-N) #7517

Piston return spring

#7802

Thrust washers
#7809

Troubleshooting Guide

Fluid leaks out the drain hole

• Fluid leaking out the drain hole

on the side of the valve indi­cates the needle packings are
worn. Replace needle packings.

Inconsistent deposits

• Inconsistent deposits can result

if the air pressure controlling
the valve and/or supplying the
reservoir is fluctuating or if the
valve operating pressure is less
than 70 psi (4.8 bar). Check to
be sure air pressures are constant
and the valve operating pressure
is 70 psi (4.8 bar).

• The time the valve is open must

be constant. Check to be sure
the valve controller is providing
a consistent output.

No fluid flow

• If valve operating air pressure is

too low, the valve will not open.
Increase air pressure to 70 psi
(4.8 bar) minimum.

• The reservoir air pressure may

not be high enough. Increase
pressure.

• The needle stroke adjustment

may be closed. Open stroke
adjustment.

• Material may have clogged the

fluid body or output tip adapter.
Clean the valve.

Steady drip

• A steady drip can be caused by

a worn needle and seat, or a
particle holding the needle off the
seat. Clean and inspect the needle
and seat for wear. Replace worn
or damaged parts.

A NORDSON COMPANY

USA: 800-556-3484 or [phone]
Europe: 0800 585733 or [phone]
Asia: [phone]
[e-mail] www.efd-inc.com

©2006 Nordson Corporation 741V-MAINT-01 v062606