Installation and maintenance guide
AIRLESS spray gun
Model S720
Copyright ALFRED SCHÜTZE Apparatebau GmbH,
2021. All rights reserved.
34
Doc-ID 1261
Replacing the seal
Fig. 6.3.1/1
1. Proceed as described up to
Section 3
in
ch. 6.3
.
2. Unscrew the nozzle.
3. Using a valve needle unit (
3
) as an installation aid, install the following parts in the given
order: Thrust washer (
11
), 2 plate springs (
10
= hollow sides against each other), guide for
plate springs (
9
), PTFE collar (
8
) and pressure cone (
7
) are fitted in this order and are then
inserted in the gun body so that the complete sealing unit is located in the front area of the
sealing chamber of the gun.
4. As when adjusting the seal, the pressure on the collar and the pressure cone is increased
by turning the pressure screw (
11
) in a clockwise direction.
5. Because the nozzle has been unscrewed and removed, you can check by inserting from
the front whether the needle requires a little pressure to pass through the PTFE collar but
still passes smoothly.
6. The spray gun is then re-assembled by carrying out the same steps in reverse order.
1. If there are any leaks in the sealing area
(this can be seen by spray material escaping
between the trigger (6) and the main body
(2)), you should depressurise the liquid in
the system.
2. The unscrew the adjusting unit (5) from the
gun. Pull out the valve needle unit (3) with
the pressure spring (4)
(Important: (The adjusting unit is under
spring tension!)
3. Remove the two shoulder screws (1) from
the trigger (6)
4. You can now use a screwdriver to turn the
sealing screw (5.1.2) slightly in a clockwise
direction. This increases the pressure on the
PTFE collar (and the pressure cone). The
pressure screw must be turned clockwise in
small increments. Repeatedly re-insert the
needle to check whether the needle requires
some pressure to pass through the PTFE
collar but still passes smoothly. The needle
must not stick.
5. If the PTFE collar (8) is no longer completely
airtight due to wear and tear, it must be
replaced (see ch.6.3.1)
1. Proceed as described up to Section 3 in ch. 6.3.
2. Unscrew the nozzle.
3. Using a valve needle unit (3) as an installation
aid, install the following parts in the given
order: Thrust washer (11), 2 plate springs (10
= hollow sides against each other), guide for
plate springs (9), PTFE collar (8) and pressure
cone (7) are fitted in this order and are then
inserted in the gun body so that the complete
sealing unit is located in the front area of the
sealing chamber of the gun.
4. As when adjusting the seal, the pressure on the
collar and the pressure cone is increased by
turning the pressure screw (11) in a clockwise
direction.
5. Because the nozzle has been unscrewed and
removed, you can check by inserting from
the front whether the needle requires a little
pressure to pass through the PTFE collar but
still passes smoothly.
6. The spray gun is then re-assembled by carrying
out the same steps in reverse order.
6.3 Adjusting and replacing the seal
6.3.1 Replacing the seal
AIRLESS spray gun
Model S720
Copyright ALFRED SCHÜTZE Apparatebau GmbH,
2021. All rights reserved.
33
Doc-ID 1261
Adjusting and replacing the seal
Fig. 6.3/1
1. If there are any leaks in the sealing area (this can be seen by spray material escaping
between the trigger (
6
) and the main body (
2
)), you should depressurise the liquid in the
system.
2. The unscrew the adjusting unit (
5
) from the gun. Pull out the valve needle unit (
3
) with the
pressure spring (
4
)
(Important: (The adjusting unit is under spring tension!)
3. Remove the two shoulder screws (
1
) from the trigger (
6
)
4. You can now use a screwdriver to turn the sealing screw (5.1.2) slightly in a clockwise
direction. This increases the pressure on the PTFE collar (and the pressure cone). The
pressure screw must be turned clockwise in small increments. Repeatedly re-insert the
needle to check whether the needle requires some pressure to pass through the PTFE collar
but still passes smoothly. The needle must not stick.
5. If the PTFE collar (
8
) is no longer completely airtight due to wear and tear, it must be
replaced (see
ch.6.3.1)
