LPR
(LOW PRESSURE REGULATOR)
- Adjustments and Maintenance.
When servicing your marker:
• Make sure your hopper is removed
from the DM4.
• Make sure there are no paintballs in the
breech of the DM4.
• Always remove the air supply and
relieve all gas pressure in the DM4
before disassembly.
• It is not recommended for the user to
remove the LPR from the body and
disassemble it.
LPR ASSEMBLY, CLEANING, TESTING AND CHANGING SEALS.
The Low-Pressure Regulator (LPR) is located in the lower back of the DM4
[see figure 1]
. The function of the LPR is to lower the
air pressure supplied to the marker by the in-line, before it reaches the solenoid. This pressure is used to move the bolt
forward and back. The factory setting is 75 PSI. You can fine tune your DM4 to its minimum cycle pressure. This will reduce
the amount of force of the bolt hitting the ball (reducing ball breaks) and help with efficiency. Too low of pressure will cause
the bolt to not cycle or move sluggishly or not at all. If you experience dramatic shoot down during rapid fire, the LPR may be
adjusted too low. Too high of pressure will cause the marker not to shoot as smoothly, potentially increase ball breakage, and
cause undue wear and fatigue on the bolt components.
It is important to keep the seat and piston face clean of all dirt and debris. Clean the seat and piston face, and grease the
retainer o-ring every three months or 20,000 shots. Every six months Remove the LPR. Clean all dirt and old grease out of the
LPR. Inspect all o-rings for damage, and apply new grease to all the o-rings and sealing surfaces.
The LPR has five components and six seals
1
Piston large o-ring (014)
6
Piston small o-ring (006)
2
Piston
7
Main seal (mounted in the seal retainer)
3
Piston spring
8
Seal retainer o-ring (010)
4
Body
9
Seal retainer (functions as an adjustment screw also)
5
Body o-rings (3pcs, 015)
10 LPR back cover
The only user-serviceable part in the LPR is the seal retainer. This seal needs to be changed in the unlikely case the LPR is creeping up.
CHANGING THE SEAL RETAINER.
1
Screw out LPR back cover behind the marker using a 1/4” allen.
2
Screw out LPR seal assembly (brass) using a 3/16” allen.
3
Screw in new LPR seal assembly.
4
Screw LPR back cover in place securely.
If the user needs to replace the whole LPR assembly, follow these instructions:
1
Take frame off the marker.
2
Screw out LPR set screw using a 5/64” allen.
3
Screw out LPR cap using a 1/4” allen.
4
Pull out the LPR by screwing a rod with a 10/32 thread into the seal retainer (brass piece) inside the LPR and pulling it out.
5
Put everything back in reverse order. Be sure to grease the #5 o-rings, as to not cut them upon installation.
6
Tighten LPR back cover securely.
The LPR pressure can bet set quite accurately even without an LPR test tool. Screwing the adjustment screw (seal retainer) all the way in will set
the LPR pressure to approximately 25 psi. Now turning out the adjusting screw 180 degrees will increase the pressure by approximately 5 psi. For
example, turning the screw 5 complete turns out will set the pressure to approximately 75 psi. Use a 3/16” Allen wrench to make all adjustments
to the LPR.
Turning the adjustment screw clockwise, or in, will lower the LPR’s output pressure. Turning the adjustment screw
counterclockwise, or out, will raise the LPR’s output pressure.
Figure 1
W A R N I N G
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4
5
5
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6
7
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10
When servicing your marker:
• Make sure your hopper is removed
from the DM4.
• Make sure there are no paintballs in the
breech of the DM4.
• Always remove the first stage regulator
and relieve all residual gas pressure from
the DM4 before disassembly.
• The DM4 can hold a small residual charge
of gas, typically 2 shots, with the first stage
regulator removed. Always discharge the
marker in a safe direction to relieve this
residual gas pressure.
W A R N I N G
ON/OFF VALVE
- Maintenance and Changing O-rings.
ON/OFF: USAGE AND CHANGING O-RINGS.
The On / Off knob is located under the barrel in the front of the DM4
[see figure 1]
. Using the on / off is simple. To turn
the gas off, turn the knob so that is is facing sideways. If you had gas inside the marker it will bleed out. To turn the gas
on, turn the knob so that it faces vertically.
The ON/OFF has three o-rings
1
009 UR90
2
012
In case of a leak from the on/off, it is easy to service:
1
Take the frame of the marker.
2
Unscrew set screw holding on/off in place (screw just in front of the front frame screw).
3
Pull out on/off, change damaged o-ring(s).
4
Lube with grease.
5
Push back in.
6
Screw in set screw.
7
Put frame back on.
8
Gas up and test.
MAINTENANCE
The on/off needs very little maintenance. To help prevent o-ring failure and leaks, grease the on/off every four months,
or sooner depending on the severity of playing conditions. Cold, wet weather will shorten the effective life of the grease.
Heavy dust or fine sand can infiltrate the on/off and prevent it from moving smoothly and or cut the o-rings.
NOTE:Air may still be present in the LPR and solenoid after the air has been vented from the gun, by the on/off. Be sure
all air has been vented by discharging the gun in a safe direction. If servicing the gun removal of the bolt will also allow
any trapped air to escape.
10
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Figure 1
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