9
5.0 Maintenance
CAUTION:
The heatless desiccant dryer is a pressure contain-
ing device. Depressurize before servicing. (See section 4.6.)
5.1 Desiccant Replacement
IMPORTANT:
The use of the correct replacement desiccant
is necessary for proper drying operation. Never use hygro-
scopic salts of the type commonly used in “deliquescent”
type dryers.
A. Frequency of Desiccant Replacement - Desiccant should
be replaced whenever the required dew point cannot be
maintained while the dryer is being operated within its
design conditions and there are no mechanical malfunc-
tions.
NOTE:
Desiccant life is determined by the quality of the
inlet air. Proper filtering of the inlet air will extend the life
of the desiccant.
B. Procedure for Desiccant Replacement
1. Depressurize and de-energize the dryer.
2. Remove front panel from cabinet.
3. Disconnect tubing from top and bottom of desic-
cant towers and unscrew strainer assemblies. Remove
the mounting screws from the outlet shuttle valve
mounting bracket to aid in disconnecting the tubing
at the top of the towers.
NOTE:
Be prepared to catch the desiccant being
removed in a container. Desiccant will readily pour out
when bottom strainer is removed.
4. Allow the spent desiccant to drain from the towers.
5. Replace bottom strainer assemblies.
6. Fill the desiccant drying towers as full as possible with
dry desiccant.
7. Replace top strainer assemblies.
8. Reinstall tubing to top and bottom of desiccant
towers.
C. Ensuring Desiccant Dryness
1. Replacement desiccant is shipped in air tight contain-
ers. Keep containers closed until use to avoid mois-
ture contamination. If desiccant is exposed to air it can
be heated in an oven at 400°F for four hours before
use, or the next procedure can be used.
2. If the dryer is not refilled with dry desiccant, it will be
necessary to operate the dryer on 100% purge for ap-
proximately twenty-four hours to dry the desiccant.
Amount of desiccant required for complete change
MODEL
DESICCANT REQUIRED
lb
(kg)
7
13
20
25
30
35
50
7
12.8
19.4
28.7
28.7
33.6
47.6
(3.2)
(5.8)
(8.8)
(13.0)
(13.0)
(15.2)
(21.6)
5.2 Prefilter/Afterfilter Maintenance
A. Element Replacement
1. For maximum filtration efficiency, replace element an-
nually or when pressure drop reaches 4.3 psi (0.3 bar)
(indicator in red area), whichever occurs first.
B. Procedure for Element Replacement
WARNING:
THIS FILTER IS A PRESSURE CONTAINING DEVICE.
DEPRESSURIZE BEFORE SERVICING.
1. Isolate filter (close inlet and outlet valves if installed) or
shut off air supply.
2. Depressurize filter by slowly opening manual drain
valve.
3. Remove bowl by unscrewing the bowl from the filter
head using hand, strap wrench or C spanner, and pull-
ing bowl straight down.
4. Clean filter bowl.
5. Replacing complete element.
a) Pull off old element and discard.
b) Make certain that the old and new element have
the same part number and the end caps are the
same color.
c) Wipe the wall inside the filter head to remove any
dirt.
d) Lubricate the new element o-ring on the element
top cap.
e) Align the slot in the element top cap with the pro-
jection inside the filter head.
Figure 6
f) Insert the element into the head making sure the
element slot and the projection inside the filter
head remain aligned.
NOTE: Handle all elements by bottom end cap only.
Projection
Element Slot
O-Ring
