Nordson EFD 725DA-SS Manual

725DA-SS and 725DA Piston Valves
MAINTENANCE & PARTS GUIDE
IMPORTANT!
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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)
[email protected] www.efd-inc.com
EFD International Inc.
Dunstable, Bedfordshire, UK
0800 585733 or [phone]
Ireland 00800 8272 9444
[email protected] www.efd-inc.com
EFD, Inc., Asia
China: [phone]
[email protected] www.efd-inc.com/cn
Singapore: [phone] [email protected]
A NORDSON COMPANY

Fluid
inlet fitting
#7543BP
Shaft
#72537
Diaphragm
#72536
Shoulder
Fluid body
#72558A-SS
Sealing head
with screw
#72557
Body cap
#72543-SS
includes O-ring
Tip adapter
#2186BP
1/4 NPT
O-ring
#72540A
(Viton®)
Air cylinder
wall ID
Air cylinder
body assembly
#72560A
O-ring
#72530A
(Buna)
CAUTION: To prevent damage, the valve
must be disassembled starting at the fluid
outlet end of the valve.
1
234
5
8
1. Put threaded rod in mounting hole.
2. Remove body cap.
3. Remove sealing head.*
4. With a wrench on the flats of the
air cylinder body, turn to loosen
fluid body.
5. Remove fluid body.*
Note: For the 725DA-SS or 725DA, valve
set stroke adjustment to the full open
position (two complete rotations). The
stroke adjustment must stay open
throughout reassembly.
6. Remove input air hose from
push-in fitting on air cap.
7. Insert 1/8” hex wrench through air
inlet hole in cap and back shaft
locking screw out two turns.*
8. Using the the hex on the shaft,
unthread shaft, and remove shaft
and diaphragm.*
9. Unscrew air cyclinder cap from air
cylinder body.*
10. Remove piston and spring.
Note: Stroke adjustment ring on
the valve air cylinder assembly is
not removable. If this assembly
requires repair, it must be
returned to EFD.
Valve Disassembly and
Reassembly Procedures
www.efd-inc.com [email protected] USA 800-556-3484 Europe [phone] Asia [phone]
Sales and service of EFD dispensing systems are available worldwide.

6
79
10
General Maintenance Kit
#725DA-RK
Includes air cylinder and body cap
O-rings, diaphragm, sealing head
with screw and lubricant.
Maintenance Tools:
1/8” hex wrench
1/4” flat-tip screwdriver
3/8” box wrench
(2) 8” adjustable wrenches
1/8 NPT male pipe or rod
Note: Before reassembling valve,
clean all parts, replace O-rings,
sealing head and diaphragm.
Inspect for damaged threads,
piston pins for straightness and
fluid body seat for pitting.
Reassemble the valve in reverse
order of disassembly. Lubricate
parts indicated with Nye Lubricant
#865 included in the General
Maintenance Kit.
step part newton meters (inch pounds)
3 Sealing head screw 1.69 Nm (15 inch pounds)
5 Fluid body 6.78 Nm (5 foot pounds)
7 Shaft locking screw 2.82 Nm (25 inch pounds)
8 Shaft 1.69 Nm (15 inch pounds)
9 Air cylinder cap 10.8 Nm (8 foot pounds)
*Parts that require a specific torque when reassembling the valve.
Air cylinder cap
with O-ring
#72530
O-ring only
#72530A (Buna)
Shaft locking screw
#72559A
Air piston with O-ring
#72555
O-ring only
#72532A
(Buna N)
Spring #72534
Push-in fitting
1/8 NPT x 1/4 OD
#2184
725DA-SS assembly of piston,
diaphragm and shaft.
www.efd-inc.com [email protected] USA 800-556-3484 Europe [phone] Asia [phone]
Sales and service of EFD dispensing systems are available worldwide.

Troubleshooting Guide
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 dispensing tip may be clogged.
Replace tip.
•The stroke adjustment may be
closed. Open stroke adjustment.
•Fluid may have solidified in the fluid
body. Clean the fluid body.
•Fluid supply line is installed in blind
mounting hole. Remove and reinstall
properly.
Fluid drools after the valve closes,
eventually stopping
•This is caused when air is trapped
in the outlet section of the fluid
body or the fluid has entrapped air.
The air will expand after the valve
closes, causing extrusion until the
air reaches atmospheric pressure.
Purge the valve by dispensing at
a steady flow until clear. If a small
tip is used, it may be necessary
to remove the tip while purging to
obtain sufficient flow to carry the
air down through the tip adapter.
•If the fluid has entrapped air, the
material must be degassed before
dispensing.
Note: For stripes and lines, input air
pressure can be lowered to elimi-
nate opening surge.
Fluid drips at a steady rate after the
valve closes
•A steady drip indicates failure of
the sealing head to close fully due
to particle buildup or wear. In either
case, replace the sealing head in
accordance with the maintenance
instructions.
Valve responds slowly when
opening and closing
•Valve response is related to control
air hose length and size. The EFD
valve is supplied with 5 feet of 1/8”
tubing attached. Any additional
length or size change will affect
response time. Check to be sure
the length and size have not been
changed.
Fluid flows out of the drain hole
•Fluid flowing out of the drain hole
indicates a ruptured diaphragm.
Replace in accordance with the
maintenance instructions.
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.
A NORDSON COMPANY
USA: 800-556-3484 or [phone]
Europe: 0800 585733 or [phone]
Asia: [phone]
[email protected] www.efd-inc.com
©2006 Nordson Corporation 725DA-MAINT-01 v062606