Nordson A7A Reference guide

A7A Single and Dual
Automatic Airless Spray Guns
Customer Product Manual
Part 1072640A
Issued 7/19
NORDSON CORPORATION •AMHERST, OHIO •USA
For parts and technical support, call the Industrial Coating
Systems Customer Support Center at [phone] or
contact your local Nordson representative.
This document is subject to change without notice.
Check http://emanuals.nordson.com for the latest version.

Part 1072640A E2019 Nordson Corporation
tents
Table of Contents
Safety 1.......................................
Qualified Personnel 1.........................
Intended Use 1..............................
Regulations and Approvals 1..................
Personal Safety 2............................
High-Pressure Fluids 2.....................
Fire Safety 3................................
Halogenated Hydrocarbon Solvent Hazards 4.
Action in the Event of a Malfunction 4...........
Disposal 4..................................
Description 5..................................
Specifications 5..............................
Theory of Operation 6.........................
Installation 7..................................
Mounting 7..................................
Fluid Connections 7...........................
Trigger Air Connection 8.......................
Optional Air-Release Valve 8................
Optional Quick Exhaust Valve 8.............
Maintenance 9................................
Troubleshooting 9.............................
Repair 10......................................
Disassembly 10...............................
Cleaning and Inspection 10.....................
Assembly 12..................................
Parts 13.......................................
Using the Illustrated Parts List 13...............
Quick Reference 14...........................
A7A Gun List 14...........................
Recommended Spare Parts 14...............
Service Parts, Kits, and Options 15...........
Single Chamber Guns 16......................
Standard Single-Chamber Gun
with Ball and Seat 17.......................
Standard Single-Chamber Gun
with Needle and Seat 18....................
High Pressure, Non-Corrosive Single-Chamber
Gun with Nickel-Carbide Ball and Seat 19.....
High Speed Single-Chamber Gun
with Nickel-Carbide Ball and Seat 20..........
Stainless Steel Single-Chamber Gun
with Needle and Seat 21....................
Stainless Steel Waterborne Single-Chamber
Gun with Nickel-Carbide Ball and Seat 22.....
Large Passage Single-Chamber Gun
with Ball and Seat 23.......................
Compound and Extended Guns 24..............
Compound Single-Chamber Gun
with Ball and Seat 25.......................
Extended Single-Chamber Gun
with Needle and Seat 26....................
Straight Dual-Chamber Guns 27................
Standard Straight Dual-Chamber Gun
with Needle and Seat 28....................
High Pressure, Non-Corrosive Straight
Dual Chamber Gun with Nickel-Carbide
Ball and Seat 29...........................
Stainless Steel Straight Dual-Chamber Gun
with Needle and Seat 30....................
Stainless Steel Waterborne Straight
Dual-Chamber Gun with Nickel-Carbide
Ball and Seat 31...........................
Angled Dual Chamber Guns 32.................
Standard Angled Dual-Chamber Gun
with Ball and Seat 33.......................
Stainless Steel Angled Dual-Chamber Gun
with Needle and Seat 34....................
Waterborne Angled Dual-Chamber Gun
with Nickel-Carbide Ball and Seat 35..........
Service Kits 36...............................
Piston and Seals Kit 36.....................
Standard Single-Chamber Ball and Seat Kit 36.
Non-Corrosive and Waterborne Single-
Chamber Nickel-Carbide Ball and Seat Kit 36..
Single-Chamber Needle and Seat Kit 37.......
Extended Needle and Seat Service Kit 37.....
Waterborne Dual Chamber Ball and Seat Kit 37
Standard Angled Dual-Chamber
Ball and Seat Kit 37.........................
Angled Dual-Chamber Ball and Seat
with Retainer Kit 38.........................
Dual-Chamber Needle and Seat Kit 38........
Dual Chamber Needle and Seat with
Retainer Kit 38.............................
Conversion Kits 39............................
Air Cylinder with Detent Adjustment 39.........
High Pressure Conversion Kit 40..............
Standard Angled Dual-Chamber Gun with
Ball and Seat Conversion Kit 40..............
Stainless Steel Angled Dual-Chamber Gun
with Needle and Seat Conversion Kit 41.......
Stainless Steel Straight Dual Chamber
Gun Retrofit Kit 42.............................
Contact Us
Nordson Corporation welcomes requests for information, comments, and
inquiries about its products. General information about Nordson can be
found on the Internet using the following address:
http://www.nordson.com.
Address all correspondence to:
Nordson Corporation
Attn: Customer Service
555 Jackson Street
Amherst, OH 44001
Notice
This is a Nordson Corporation publication which is protected by copyright.
Original copyright date 1987. No part of this document may be
photocopied, reproduced, or translated to another language without the
prior written consent of Nordson Corporation. The information contained
in this publication is subject to change without notice.
Trademarks
Cross-Cut, Nordson, and the Nordson logo are registered trademarks of
Nordson Corporation.
Loctite is a registered trademark of Loctite Corporation.
Viton is a registered trademark of DuPont Dow Elastomers. L.L.C.

A7A Single and Dual Automatic Airless Spray Guns 1
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A7A Single and Dual
Automatic Airless Spray Guns
Safety
Read and follow these safety instructions. Task- and equipment-specific
warnings, cautions, and instructions are included in equipment
documentation where appropriate.
Make sure all equipment documentation, including these instructions, is
accessible to persons operating or servicing equipment.
Qualified Personnel
Equipment owners are responsible for making sure that Nordson equipment
is installed, operated, and serviced by qualified personnel. Qualified
personnel are those employees or contractors who are trained to safely
perform their assigned tasks. They are familiar with all relevant safety rules
and regulations and are physically capable of performing their assigned
tasks.
Intended Use
Use of Nordson equipment in ways other than those described in the
documentation supplied with the equipment may result in injury to persons
or damage to property.
Some examples of unintended use of equipment include
Susing incompatible materials
Smaking unauthorized modifications
Sremoving or bypassing safety guards or interlocks
Susing incompatible or damaged parts
Susing unapproved auxiliary equipment
Soperating equipment in excess of maximum ratings
Regulations and Approvals
Make sure all equipment is rated and approved for the environment in which
it is used. Any approvals obtained for Nordson equipment will be voided if
instructions for installation, operation, and service are not followed.

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Personal Safety
To prevent injury follow these instructions.
SDo not operate or service equipment unless you are qualified.
SDo not operate equipment unless safety guards, doors, or covers are
intact and automatic interlocks are operating properly. Do not bypass or
disarm any safety devices.
SKeep clear of moving equipment. Before adjusting or servicing moving
equipment, shut off the power supply and wait until the equipment
comes to a complete stop. Lock out power and secure the equipment to
prevent unexpected movement.
SRelieve (bleed off) hydraulic and pneumatic pressure before adjusting or
servicing pressurized systems or components. Disconnect, lock out,
and tag switches before servicing electrical equipment.
SWhile operating manual spray guns, make sure you are grounded.
Wear electrically conductive gloves or a grounding strap connected to
the gun handle or other true earth ground. Do not wear or carry metallic
objects such as jewelry or tools.
SIf you receive even a slight electrical shock, shut down all electrical or
electrostatic equipment immediately. Do not restart the equipment until
the problem has been identified and corrected.
SObtain and read Material Safety Data Sheets (MSDS) for all materials
used. Follow the manufacturer’s instructions for safe handling and use
of materials, and use recommended personal protection devices.
SMake sure the spray area is adequately ventilated.
STo prevent injury, be aware of less-obvious dangers in the workplace
that often cannot be completely eliminated, such as hot surfaces, sharp
edges, energized electrical circuits, and moving parts that cannot be
enclosed or otherwise guarded for practical reasons.
High-Pressure Fluids
High-pressure fluids, unless they are safely contained, are extremely
hazardous. Always relieve fluid pressure before adjusting or servicing high
pressure equipment. A jet of high-pressure fluid can cut like a knife and
cause serious bodily injury, amputation, or death. Fluids penetrating the
skin can also cause toxic poisoning.
If you suffer a fluid injection injury, seek medical care immediately. If
possible, provide a copy of the MSDS for the injected fluid to the health care
provider.

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The National Spray Equipment Manufacturers Association has created a
wallet card that you should carry when you are operating high-pressure
spray equipment. These cards are supplied with your equipment. The
following is the text of this card:
WARNING: Any injury caused by high pressure liquid can be serious. If
you are injured or even suspect an injury:
SGo to an emergency room immediately.
STell the doctor that you suspect an injection injury.
SShow him this card
STell him what kind of material you were spraying
MEDICAL ALERT—AIRLESS SPRAY WOUNDS: NOTE TO PHYSICIAN
Injection in the skin is a serious traumatic injury. It is important to treat the
injury surgically as soon as possible. Do not delay treatment to research
toxicity. Toxicity is a concern with some exotic coatings injected directly into
the bloodstream.
Consultation with a plastic surgeon or a reconstructive hand surgeon may
be advisable.
The seriousness of the wound depends on where the injury is on the body,
whether the substance hit something on its way in and deflected causing
more damage, and many other variables including skin microflora residing
in the paint or gun which are blasted into the wound. If the injected paint
contains acrylic latex and titanium dioxide that damage the tissue’s
resistance to infection, bacterial growth will flourish. The treatment that
doctors recommend for an injection injury to the hand includes immediate
decompression of the closed vascular compartments of the hand to release
the underlying tissue distended by the injected paint, judicious wound
debridement, and immediate antibiotic treatment.
Fire Safety
To avoid a fire or explosion, follow these instructions.
SGround all conductive equipment. Use only grounded air and fluid
hoses. Check equipment and workpiece grounding devices regularly.
Resistance to ground must not exceed one megohm.
SShut down all equipment immediately if you notice static sparking or
arcing. Do not restart the equipment until the cause has been identified
and corrected.
SDo not smoke, weld, grind, or use open flames where flammable
materials are being used or stored.
SDo not heat materials to temperatures above those recommended by
the manufacturer. Make sure heat monitoring and limiting devices are
working properly.

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Fire Safety (contd)
SProvide adequate ventilation to prevent dangerous concentrations of
volatile particles or vapors. Refer to local codes or your material MSDS
for guidance.
SDo not disconnect live electrical circuits when working with flammable
materials. Shut off power at a disconnect switch first to prevent
sparking.
SKnow where emergency stop buttons, shutoff valves, and fire
extinguishers are located. If a fire starts in a spray booth, immediately
shut off the spray system and exhaust fans.
SShut off electrostatic power and ground the charging system before
adjusting, cleaning, or repairing electrostatic equipment.
SClean, maintain, test, and repair equipment according to the instructions
in your equipment documentation.
SUse only replacement parts that are designed for use with original
equipment. Contact your Nordson representative for parts information
and advice.
Halogenated Hydrocarbon Solvent Hazards
Do not use halogenated hydrocarbon solvents in a pressurized system that
contains aluminum components. Under pressure, these solvents can react
with aluminum and explode, causing injury, death, or property damage.
Halogenated hydrocarbon solvents contain one or more of the following
elements:
Element Symbol Prefix
Fluorine F “Fluoro-”
Chlorine Cl “Chloro-”
Bromine Br “Bromo-”
Iodine I “Iodo-”
Check your material MSDS or contact your material supplier for more
information. If you must use halogenated hydrocarbon solvents, contact
your Nordson representative for information about compatible Nordson
components.
Action in the Event of a Malfunction
If a system or any equipment in a system malfunctions, shut off the system
immediately and perform the following steps:
SDisconnect and lock out system electrical power. Close hydraulic and
pneumatic shutoff valves and relieve pressures.
SIdentify the reason for the malfunction and correct it before restarting the
system.
Disposal
Dispose of equipment and materials used in operation and servicing
according to local codes.

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Description
A7A automatic guns are compact, high-cycle, airless spray guns designed
for use with solvent or waterborne coatings. They are air-operated,
actuated by remote electro-pneumatic solenoids. They can be used for
general finishing as well as ultra-high speed applications.
A7A guns are available in single-chamber, straight dual-chamber and
angled dual chamber models. The dual-chamber models permit the user to
quickly switch between two different coatings with no downtime. Kits are
available to convert two single-chamber A7A guns to one straight or angled
dual-chamber gun, or a straight dual-chamber gun to an angled gun.
Refer to the A7A Gun List on page 14 for a list of all available models.
1300450A
Single-Chamber Straight Dual-Chamber Angled Dual-Chamber
Figure 1 A7A Spray Gun Models
Specifications
Properties Single-Chamber Dual-Chamber Dual-Chamber
Angled
Maximum Fluid Pressure, bar (psi)
Standard 117 (1700) 117 (1700) 117 (1700)
With High-Pressure Option Kit 207 (3000) 207 (3000) 207 (3000)
Air Trigger Requirements, bar (psi) 2.75–8.27 (40–120) 2.75–8.27 (40–120) 2.75–8.27 (40–120)
Dimensions, cm (in.)
Height 8.9 (3.5) 11.1 (4.375) 11.7 (4.625)
Length 8.9 (3.5) 13.3 (5.25) 15.2 (6.0)
Width 8.9 (3.5) 8.9 (3.5) 8.9 (3.5)
Weight, kg (oz) 0.45 (0.94) 1.43 (3.15) 1.20 (2.65)
Fittings
Fluid (In and Out) 1/2−20 JIC* 1/2−20 JIC 1/2−20 JIC
Air 1/8in. NPT female 1/8in. NPT female 1/8in. NPT female
Mounting 13-mm (1/2-in.)
round bar
13-mm (1/2-in.)
round bar
13-mm (1/2-in.)
round bar
* Compound guns use 3/4-16 JIC fluid fittings.

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Theory of Operation
See Figure 2. This figure shows a cutaway view of a dual-chamber A7A
gun. The dual-chamber gun is two single-chamber guns mounted on a
manifold, sharing a single nozzle. Only one chamber is triggered at a time.
To trigger the gun, air pressure is applied to the bottom of the piston
assembly (2), which lifts the needle (4) off the seat (5). Coating flows
through the seat to the nozzle (8). When the air pressure is removed, the
spring in the packing cartridge (3) returns to the needle to the seat and
stops the flow of the coating material to the nozzle.
The packing cartridge seals prevent coating material from contaminating the
air piston. If the seals fail, coating material will flow out of the weep holes
above the fluid fittings.
1300451A
1
21
6
7
5
4
3
8
Figure 2 Gun Operation
1. Air fitting
2. Piston assembly
3. Packing cartridge
4. Needle
5. Seat
6. Fluid fittings (inlet and outlet)
7. Nozzle nut
8. Nozzle

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Installation
WARNING: Allow only qualified personnel to perform the following tasks.
Follow the safety instructions in this document and all other related
documentation.
Figure 3 shows a typical coating system installation.
1300452A
34 5
6
8
9
7
1
10
2
Figure 3 Typical Circulating System
1. Pump
2. Heater
3. Filter
4. Solenoid valve
5. Air regulator
6. A7A gun
7. Ball valves
8. Circulation valve
9. Drain off rod
10. Coating supply
Mounting
Slide a 13-mm (1/2-in.) round mounting bar through the hole in the mounting
block, orient the gun as desired, and tighten the square head screw.
Fluid Connections
WARNING: In the fluid supply line, install an approved pressure relief
device set to the lowest maximum working pressure of all system
components. The fluid hoses must have a minimum burst pressure greater
than the pressure relief device setting.
CAUTION: Do not overtighten the fluid fittings. You can strip the threads in
the gun body.
Apply pipe thread adhesive (shipped with the gun) to the two fluid fittings
and install them in the gun body. If your system is dead-ended
(non-circulating), install one fitting and the 1/4-in. NPT plug furnished with
the gun. Connect the fluid supply and return hoses to the fluid fittings.
Either fitting can be used for supply or return.

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Trigger Air Connection
Use an electro-pneumatic solenoid valve to trigger the gun. For the fastest
trigger response, connect the solenoid valve directly to the gun at the
1/8-in. NPT air inlet fitting. If this is not possible, install the valve as close to
the gun as possible, and use the shortest length of air tubing possible.
NOTE: If the trigger air tubing is too long, it can cause trigger on/off delays,
spitting, and premature wear of the ball or needle and seat. If you cannot
shorten the air tubing, install an optional air-release valve on the gun.
Optional Air-Release Valve
See Figure 4. Refer to Options on page 15 for the air-release valve part
number. The air-release valve
Sreduces the cycle time of the A7A gun, if the speed of operation is less
than 600 cycles per minute.
Smay be used when the electro-pneumatic solenoid valve cannot be
installed on the gun. With this option, 100-ft air line lengths are
practical.
Sreduces wear on the ball or needle and seat if operating the gun at high
speed.
Sallows one solenoid valve to trigger several guns.
Sprovides precise gun triggering from a remote timer, eliminates poor
gun/timer resolution, and saves coating material.
NOTE: The trigger air pressure must remain constant. Limit the diameter
of the pilot air lines (5) to prevent spitting and other problems.
1300453A
1 2 3 4
5
7
6
Figure 4 Typical Air Release Valve Installation
1. Filter
2. Gauge
3. Lubricator
4. Solenoid valve
5. Small diameter pilot air line
6. Air-release valves
7. Trigger air supply line
(2.7−4.1 bar (40−60 psi)
Optional Quick Exhaust Valve
The optional quick exhaust valve will allow the gun to close faster and
reduce overall cycle time. Use a 1/4-in. NPT nipple to connect the valve to
the gun, and a 1/4-in. tube x 1/8-in. NPT fitting to connect the actuating air
tubing to the valve. Refer to Options on page 15 for the exhaust valve and
fittings.

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Maintenance
Flush the gun periodically to keep the fluid passageways and ball and seat
clean and free of contaminants. As required, disassemble and clean the
gun and replace any worn parts.
Make sure the trigger air is clean and dry. Lubricate the air supply if
operating at high speeds for long periods of time.
Troubleshooting
WARNING: Allow only qualified personnel to perform the following tasks.
Follow the safety instructions in this document and all other related
documentation.
NOTE: If you cannot solve your problem with the information given here,
contact your local Nordson representative for help.
Problem Possible Cause Corrective Action
1. Leaking around nozzle
or nozzle retaining nut
Dirty or damaged metal sealing
surface
Relieve system pressure. Remove
the nozzle retaining nut and clean or
replace the nozzle or retaining nut.
2. Leaking from weep
holes in the gun body
above the fluid fittings
Worn packing cartridge Replace the packing cartridge with
the appropriate kit. Refer to Parts.
3. Spitting Dirty or worn ball and seat Clean or replace the ball and seat.
Actuating or trigger air lines too
long
Mount the solenoid on or as close as
possible to the gun. Use optional
air-release valve as shown in
Installation.
Air trapped in fluid system Purge air from system by opening the
ball valve at circulation valve and
draining system until no air bubbles
are seen, or spraying until spitting is
stopped.
Make sure the pump is not siphoning
air into the fluid system.
4. On/Off cycle response
poor or gun not
opening or closing
Air piston assembly worn or out of
adjustment
Adjust or replace the air piston
assembly.
Low air pressure to the solenoid
valve
Increase the air pressure to between
2.7−4.1 bar (40−60 psi).
Trigger air lines too long Mount the solenoid on or as close as
possible to the gun or install an air
release valve.
Fluid pressure too high Reduce the fluid pressure or install a
high-pressure kit. The guns will not
close if their maximum working
pressure is exceeded.

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Repair
WARNING: Allow only qualified personnel to perform the following tasks.
Follow the safety instructions in this document and all other related
documentation.
WARNING: Relieve trigger air pressure and system fluid pressure before
disconnecting air and fluid hoses to the spray gun. High pressure fluid is
dangerous and can cause injection injuries.
Refer to Figure 5 for both Disassembly and Assembly procedures.
Disassembly
1. Flush the gun with clean solvent.
2. Relieve system fluid and air pressure, then disconnect the fluid and air
lines from the gun.
3. To avoid having to reposition the gun on the mounting bar when you
reinstall it, unscrew the two screws (12) and remove the gun from the
mounting block (13). Otherwise, remove the gun from the mounting bar
by loosening the square head screw (14).
4. Disassembly order:
a. Remove the air cylinder (3).
b. Hold the packing cartridge stem with a wrench and remove the lock
nut (6). Unscrew the piston assembly (5) from the stem and
separate the seal nut, O-ring and piston (7, 8, 9).
c. Single Chamber: Remove the seat (19A−C) from the body (11).
d. Dual Chamber: Remove the body (11) from the manifold (25), then
remove the seat retainer, seat, and O-ring (22, 23, 24).
e. Push the packing cartridge (15) out of the body.
f. If replacing the ball or needle (16A−D), unscrew it from the packing
cartridge.
Cleaning and Inspection
1. Clean the air cylinder, packing cartridge, gun body, and seat with a
compatible cleaning solution.
2. Inspect the seat and ball or needle. If either are damaged or scored,
replace them. The ball and seat (or needle and seat) are a matched set
and only sold as a kit.
3. Inspect the piston seal. If it is damaged replace the entire piston
assembly with the piston service kit.
4. Inspect all gaskets and O-rings. Replace any that are damaged.
5. If coating material was leaking from the weep holes above the fluid
fittings, replace the packing cartridge.

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1300454A
NOTE: Ball or Needle and
Seat are matched sets and
must be replaced together.
Apply O-ring lubricant part
900223 (Parker O-Lube or
equivalent) before installing.
Apply Loctite 242 Removable
thread adhesive or equivalent
to threads before tightening.
1
2
3
4
6
7
8
10
9
13
14
15
12
11
5
17
16A
16B
16C
16D
18
19C
19B
19A
20
21
22
23
24
26
25
21
27
17
17
Dual
Chamber Guns
20
Figure 5 Repair
1. #10−32 x 1 in. screws
2. #10 lock washer
3. Air cylinder
4. Gasket
5. Piston assembly
6. #10−32 lock nut
7. Seal nut
8. O-ring
9. Piston
10. O-ring
11. Body
12. #10−32 x 2 in. screws
13. Mounting block
14. Square-head screw
15. Packing cartridge
16A. Extended needle
16B. Compound ball
16C. Needle
16D. Ball
17. O-ring
18. #10−32 x 0.50 in. screws
19A. Extended seat
19B. Compound seat
19C. Standard seat
20. Nozzle (sold separately)
21. Nozzle nut
22. Seat retainer
23. Seat
24. O-ring
25. Manifold
26. Screws
27. Compression spring
(high-pressure models only)
Note: Do not use these item numbers to order parts. Your gun part number is on the label plate on the gun body. Refer
to the gun list on page 14 to find the correct parts list for your gun. Order parts by part number and description.

A7A Single and Dual Automatic Airless Spray Guns
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Assembly
NOTE: Lubricate all O-rings with Parker O-Lube or equivalent before
installing.
See Figure 5.
1. If removed, install the O-ring (10) in the groove in the body (11).
2. Install the ball or needle (16A−D) on the end of the packing
cartridge (15).
3. Install the packing cartridge in the body.
4. Assemble the seat and gun body:
Single Chamber:
a. Install the O-ring (17) on the seat (19).
b. Install the seat on the body and tighten the screws (18) securely.
Dual Chamber:
a. Install the O-ring (17) on the seat retainer (22).
b. Install the O-ring (24), seat (23), and seat retainer in the
manifold (25).
c. Install the body on the manifold and tighten the screws (26) securely.
The angled gun uses three screws, two short and one long.
5. Assemble the piston parts (6, 7, 8, 9) on the packing cartridge stem. Do
not tighten the lock nut (6).
6. Screw the piston assembly (5) onto the packing cartridge stem
clockwise until it comes to rest against the gun body.
SIf the gun is equipped with a ball and seat, turn the piston assembly
counterclockwise 1/2to 3/4turn.
SIf the gun is equipped with a tapered needle and seat, turn the piston
counterclockwise 1 1/2turns.
7. Apply a drop of thread-locking compound to the lock nut threads. Hold
the packing cartridge stem with a small wrench while tightening the lock
nut.
8. High Pressure Guns: Install the compression spring (27) on top of the
piston.
9. Install the gasket (4) and air cylinder (3).
10. Re-install the gun on the mounting block (13) or mounting rod.

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Parts
For Technical Service or to order parts, call the Nordson Finishing Customer
Support Center at [phone], or your local Nordson representative.
Using the Illustrated Parts List
Numbers in the Item column correspond to numbers that identify parts in
illustrations following each parts list. The code NS (not shown) indicates
that a listed part is not illustrated. A dash (—) is used when the part number
applies to all parts in the illustration.
The number in the Part column is the Nordson Corporation part number. A
series of dashes in this column (- - - - - -) means the part cannot be ordered
separately.
The Description column gives the part name, as well as its dimensions and
other characteristics when appropriate. Indentions show the relationships
between assemblies, subassemblies, and parts.
SIf you order the assembly, items 1 and 2 will be included.
SIf you order item 1, item 2 will be included.
SIf you order item 2, you will receive item 2 only.
The number in the Quantity column is the quantity required per unit,
assembly, or subassembly. The code AR (As Required) is used if the part
number is a bulk item ordered in quantities or if the quantity per assembly
depends on the product version or model.
Letters in the Note column refer to notes at the end of each parts list. Notes
contain important information about usage and ordering. Special attention
should be given to notes.
Item Part Description Quantity Note
— 0000000 Assembly 1
1 000000 SSubassembly 2 A
2 000000 SS Part 1

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Quick Reference
A7A Gun List
Part Description Page
Single-Chamber Guns
153150 Standard, single chamber, with ball and seat 17
248445 Standard, single chamber, with needle and seat 18
342276 High pressure, non-corrosive, single chamber, with nickel-carbide ball and seat 19
246789 High-speed, single chamber, with nickel-carbide ball and seat 20
153160 Stainless steel, single chamber, with needle and seat 21
337303 Stainless steel, single chamber, waterborne with nickel-carbide ball and seat 22
709831 Standard, large passage, single chamber, with ball and seat 23
510010 Compound, single chamber, with ball and seat 25
245375 Extended, single chamber, with 2.5 in. valve extension and needle and seat 26
Dual-Chamber Guns
248937 Dual-chamber, standard, with needle and seat 28
342300 Dual-chamber, high pressure, non-corrosive, with nickel-carbide ball and seat 29
149097 Dual-chamber, stainless steel, with needle and seat 30
337302 Dual-chamber, stainless steel, waterborne with nickel-carbide ball and seat 31
160062 Dual-chamber, angled, standard, with ball and seat 33
160063 Dual-chamber, angled, stainless steel with needle and seat 34
337304 Dual-chamber, stainless steel, angled, waterborne, with nickel-carbide ball and seat 35
Recommended Spare Parts
Keep these parts in stock to prevent unnecessary downtime.
Part Description Usage
Order one each of the following:
901905 Brush All Guns
901911 Wrench, adjustment, module All Guns
152999 Wrench All Guns
Order one each of the following for each gun:
106230 Repair kit, piston, with seals, A7A All Guns
−Packing cartridge from Service Parts, Kits, and Options on page 15 or
from your gun parts list.
Model Specific
−Ball or needle and seat service kit from Service Parts, Kits, and Options
on page 15 or from the notes in your gun parts list.
Model Specific
−Nozzle retaining nut from your gun parts list. Model Specific

A7A Single and Dual Automatic Airless Spray Guns 15
Part 1072640A
E2019 Nordson Corporation
Service Parts, Kits, and Options
Part Description Usage
Replacement Packing Cartridges
153152 Standard, compound, dual-chamber 153150, 510010, 248937,
709831, 160062
153090 Stainless steel 248445, 342276, 153160,
337303, 245375, 342300,
149097, 337302, 160063,
337304
245778 Corrosion-resistant 246789
244918 Ketone resistant Optional
Service Kits (Order two kits to repair both modules of dual-chamber guns)
106230 Piston with seals All guns except high pressure
106231 Ball and seat, standard, single-chamber 153150
320031 Ball and seat, waterborne, single-chamber 342276, 246789, 337303
159447 Ball and seat, angled, dual-chamber 160062
134972 Ball and seat with retainer, angled, dual-chamber 160062
337305 Ball and seat, waterborne, dual-chamber and angled 342300, 337302, 337304
106280 Needle and seat, single-chamber 248445, 153160
106234 Needle and seat extended, single-chamber 245375
106416 Needle and seat, dual-chamber 248937, 149097, 160063
160354 Needle and seat with retainer, dual-chamber 248937, 149097, 160063
Conversion Kits
106311 Cylinder, with detent adjust Note A
160355 Dual A7A, angled, standard (aluminum) Note B
160060 Dual A7A, angled, stainless steel Note B
248941 High-pressure Notes A, C
248939 Retrofit kit, A7A dual-chamber gun Note D
331497 Air-assisted airless adapter Note E
Options
159146 Mounting bar, gun, universal 46-cm (18-in.)
901262 Quick exhaust valve
901028 Air release valve, normally closed
973000 Nipple, steel, schedule 40, 1/8in. NPT, 0.75 in. long Note F
971154 Connector, male, 1/4in. tube x 1/8in. NPT, brass Note F
NOTE A: Order two kits for converting both chambers of a dual-chamber gun.
B: Converts two single-chamber guns or one dual-chamber gun into an angled dual-chamber gun.
C: Increases the operating pressure range to 207 bar (3000 psi). Use on all models.
D: Converts two single-chamber guns into one dual-chamber gun.
E: Provides better atomization for certain spraying applications. Uses A7AA Cross-Cut nozzles and air cap.
Refer to instruction sheet shipped with kit for installation and parts information.
F: Use to install quick exhaust or air release valves on gun and connect air tubing to valve.

A7A Single and Dual Automatic Airless Spray Guns
16
Part 1072640A E2019 Nordson Corporation
Single Chamber Guns
See Figure 7 on page 24 and associated parts lists for Compound and
Extended A7A Guns.
1300455A
5
19
6
1
2
3
4
7
8
9
10
11
14
16
13
12
15
17
18
20
22
21
Ball
Needle
23
(High-Pressure
Models Only)
Figure 6 Single Chamber Guns (Except Compound and Extended Valve Guns)

A7A Single and Dual Automatic Airless Spray Guns 17
Part 1072640A
E2019 Nordson Corporation
Standard Single-Chamber Gun
with Ball and Seat
See Figure 6 on page 16.
Item Part Description Quantity Note
— 153150 GUN, A7A, automatic, circulating 1
1 981140 SSCREW, fillister, #10-32 x 1.00 in., slotted, zinc 4
2 983120 SWASHER, lock, , split, #10, steel, nickel 4
3 153028 SCYLINDER 1
4 153031 SGASKET, gun, H20 1 A
5 153022 SPISTON assembly, H20 1 A
6 984539 SS NUT, lock, #10-32, upper 1 A
7 240274 SS NUT, seal lock 1 A
8 940090 SS O-RING, Viton, 0.208 ID x 0.70 in., brown 1 A
9 940157 SO-RING, Viton, black, 0.562 x 0.688 in., 10415 1 A
10 973125 SELBOW, pipe, 1/8in. NPT, brass 1
11 981127 SSCREW, fillister, #10-32 x 2.00 in., slotted, zinc 2
12 153158 SBLOCK, mounting 1
13 981405 SSCREW, square, set, 3/8-16 x 0.750 in., cup,
zinc
1
14 972176 SELBOW, male, 37_, 1/2-20 x 1/4in. NPT, steel 2
15 973415 SPLUG, pipe, socket, standard, 1/4in NPT,
stainless steel
1 B
16 - - - - - - SBODY, gun 1
17 153152 SCARTRIDGE, packing 1
18 940134 SS O-RING, Viton, 0.438 x 0.563 x 0.063 in. 1
19 - - - - - - SBALL and seat 1 C
20 940174 SO-RING, Viton, black, 0.688 x 0.813 in. 1A, C
21 981115 SSCREW, oval, #10-32 x 0.50 in., slotted, zinc 4
22 152290 SNUT, retaining 1
NS 901905 SBRUSH 1
NS 901911 SWRENCH, adjustment, module 2
NS 247646 SCARD, medical alert, injection 1
NS 900431 SADHESIVE, pipe/thread/hydraulic sealant 1
NOTE A: Included in piston with seals repair kit, part 106230.
B: Used in non-circulating systems. Replaces one of the elbows, part 972176.
C: Included in ball and seat service kit, part 106231.
NS: Not Shown

A7A Single and Dual Automatic Airless Spray Guns
18
Part 1072640A E2019 Nordson Corporation
Standard Single-Chamber Gun
with Needle and Seat
See Figure 6 on page 16.
Item Part Description Quantity Note
— 248445 GUN, A7A, automatic, circulating, tapered needle
and seat
1
1 981140 SSCREW, fillister, #10-32 x 1.00 in., slotted, zinc 4
2 983120 SWASHER, lock, split, #10, steel, nickel 4
3 153028 SCYLINDER 1
4 153031 SGASKET, gun, H20 1 A
5 153022 SPISTON assembly, H20 1 A
6 984539 SS NUT, lock, #10-32, upper 1 A
7 240274 SS NUT, seal lock 1 A
8 940090 SS O-RING, Viton, 0.208 ID x 0.70 in., brown 1 A
9 940157 SO-RING, Viton, black, 0.562 x 0.688 in. 1 A
10 973125 SELBOW, pipe, 1/8in. NPT, brass 1
11 981127 SSCREW, fillister, #10-32 x 2.00 in., slotted, zinc 2
12 153158 SBLOCK, mounting 1
13 981405 SSCREW, square, set, 3/8-16 x 0.75 in., cup,
zinc
1
14 972177 SELBOW, male, 37_,1/2-20 x 1/4in. NPT,
stainless steel
2
15 973415 SPLUG, pipe, socket, standard, 1/4in NPT,
stainless steel
1 B
16 - - - - - - SBODY, gun 1
17 153090 SCARTRIDGE, packing 1
18 940134 SS O-RING, Viton, 0.438 x 0.563 x 0.063 in. 1
19 - - - - - - SNEEDLE and seat, A7A 1 C
20 940174 SO-RING, Viton, black, 0.688 x 0.813 in. 1A, C
21 981160 SSCREW, pan, #10-32 x 0.50 in., slotted, zinc 4 C
22 152290 SNUT, retaining 1
NS 901905 SBRUSH 1
NS 901911 SWRENCH, adjustment, module 2
NS 247646 SCARD, medical alert, injection 1
NS 900431 SADHESIVE, pipe/thread/hydraulic sealant 1
NOTE A: Included in piston with seals repair kit, part 106230.
B: Used in non-circulating systems. Replaces one of the elbows, part 972176.
C: Included in needle and seat service kit, part 106280.
NS: Not Shown