UH209
UH209 Series
H I G H P R E S S U R E F I LT E R S
s e r v i c e
i n s t r u c t i o n s
3
5
Routine maintenance
5.1
Pall
filters do not normally require special attention
except for periodic monitoring of the differential pressure
warning device. Schedule replacement of filter element
every six months or sooner, and have ample supply of
spare elements available.
5.2
If external leakage is noted, replace O-ring at leak. If
leakage persists, check sealing surfaces for scratches or
cracks; replace any defective parts.
5.3
Differential pressure devices actuate when the element
needs changing or because of high fluid viscosity in
'cold start' conditions. If 'cold start' conditions exist, see
Section 6.2 and 6.3.
5.4
A dirty system can quickly plug a new filter element,
especially with
Pall
high efficiency filter media. It may
require one or two initial element changes to stabilize
element life. If element life is short or differential
pressure is excessive, filter may be undersized; refer to
the sizing and selection section of the product literature
or contact your local Pall representative.
5.5
Make sure element change labels are clean and
undamaged. Replace illegible labels with the appropriate
new labels.
6
Differential pressure devices
Reference should be made to product literature for dimensions,
operating parameters, part numbering, ordering information
and specifications.
6.1
Differential pressure devices actuate when the element
needs changing or because of high fluid viscosity in
'cold start' conditions.
6.2
If visual indicator is fitted and actuates during 'cold start'
(red button extends 5mm, 3/16"), reset by depressing
the button when the normal operating temperature is
reached. If indicator actuates after resetting, replace
element.
NOTE: Option 'P' visual indicator has thermal lockout and
manual reset. No signal below 0°C (32°F), signal above 29°C
(80°F).
6.3
If the electrical switch actuates (e.g. red light comes on)
during cold start, continue operating until the signal (red
light) goes out as system warms to normal operating
temperature. This feature can be used as 'warm up'
indication in operating procedures. If the warning signal
(red light) remains or appears when system is warm,
replace the filter element.
ENGLISH
6.4
Use of both positive indication (green light) and negative
indication (red light for dirty element) is recommended to
effectively monitor filter element life.
Electrical connections and ratings for all differential
pressure switch options:
110 VAC
=
4A (inductive),
4A (resistive)
220 VAC
=
4A (inductive),
4A (resistive)
28 VDC
=
3A (inductive),
5A (resistive)
48 VDC
=
1A (inductive),
1.5A (resistive)
125 VDC
=
0.25A (inductive),
0.5A (resistive)
Maximum inrush - 24 amps.
Underwriter’s lab. Inc. listed ratings of pressure switch
(Microswitch) options are:
4 amps at 250 VAC
0.25 amp resistive at 220 VDC
0.50 amp resistive at 110 VDC
Electrical differential pressure switch operation:
When preset differential pressure is exceeded continuity
switches from 'C' - 'A' to 'C' - 'B'.
When differential pressure decreases below pre-set value,
continuity returns to 'C' - 'A'.
Figure 1
- Switch Circuit Diagram
C
or black
or tag 2
A
or white
or tag 1
B
or red
or tag 3
LOW DIFFERENTIAL PRESSURE
HIGH DIFFERENTIAL PRESSURE
