A-Dec 3420 Operation And Maintenance Instructions - page 24
Air Filter/Regulator
The supply air passes through the filter before
entering the regulator. The filter element should
be serviced when it becomes sufficiently clogged
to impede the flow to the regulator.
Servicing the Air Filter/Regulator
The air filter/regulator assembly (24.0030.00)
used in the Pac I is subject to only three types
of problems: (1) clogged filter element, (2)
external leakage, and (3) internal leakage.
To service any part of the air filter/regulator,
first locate the Air Filter/Regulator Service Kit
(A-dec Part No. 90.1066.00), which is in your
field repair kit. Included in the service kit are
an exploded drawing of the assembly and
replacement parts.
Checking the Filter
First, ensure the supply air is connected. Watch
the system air pressure gauge while pressing the
right-hand (air) button of the syringe. If the
pressure drops by more than 15 psi (103 Kpa),
the filter element is clogged and must be
replaced.
Clogged Filter Element
To replace the filter element:
1. Disconnect the supply air tubing from the control
head.
2. Relieve system pressure by pressing the syringe
air (right-hand) button, and by loosening the
water bottle.
3. From the bottom of the unit, unscrew the bowl,
remove the filter element and the filter element
retainer.
4. Install the new filter element (97.0401.00)
included in the service kit, then reinstall the
filter, retainer, and bowl.
External Leakage
In the event of external leakage, take the fol-
lowing action according to the point of leakage:
1. The leakage is coming from the purge valve at
the bottom of the filter bowl.
The leak may result from a loose or defective
purge valve.
• Tighten the purge valve.
• If the leak persists, replace the bowl
assembly which includes the purge valve
(A-dec Part Number 97.0403.00).
2. The leakage is coming from around the top of the
filter bowl.
The leak may result from a loose filter bowl, or
from a defective O-ring seal.
• Tighten the filter bowl.
3. The leakage is coming from around the top of the
regulator.
The leak may result from a loose cover or a
defective diaphragm.
• Tighten the regulator cover.
• If the leak persists, replace the
diaphragm (A-dec Part Number 97.0402.00)
Internal Leakage
If the system air pressure gauge shows that
pressure creeps up when the unit is not being
used, there is air leaking past the inlet seal.
This can normally be corrected by replacing the
poppet (97.0402.00) and spring (97.0404.00)
included in the Air-Filter Regulator Service Kit
(A-dec Part No. 90.1066.00). When installing the
new poppet, be certain there is no foreign
material on the sealing surfaces in the valve
body.
Page 20
85.0681.00 Rev J
Figure 48. Air filter/regulator assembly
Air filter/
regulator
assembly
Air
manifold
Moisture
separator,
manual
Purge valve
Filter
bowl
Cover
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