UR329
R E T U R N L I N E F I LT E R S
4.8
Ensure the valves immediately upstream and downstream of the
filter assembly are closed. Commission filter assembly as follows:
(a)
Ensure that drain and vent plugs are closed.
(b)
Open left hand housing vent plug one and one half turns.
(c)
Position change-over valve to the left, to allow flow through left
hand housing.
(d)
Jog system and fill filter with oil. Close vent plug when bubble free
fluid issues from port and torque tighten to 12 ft/lb or 16 Nm.
Pressurize system fully and check for leaks; if leaks occur refer
to section 5.
(e)
Shut down and depressurize system.
(f)
Open right hand housing vent plug one and one half turns.
(g)
Position change-over valve to right, to allow flow through right
hand housing. Position change-over valve to right, to allow flow
through right hand housing.
(h)
Jog system and fill filter with oil. Close vent plug when bubble
free fluid issues from port and torque tighten to 12 ft/lb or 16 Nm.
Pressurize system fully and check for leaks; if leaks occur refer
to section 5.
(i)
On completion of commisioning sequence, the assembly is ready
for service. Shut down and depressurize system. Position change-
over valve to place selected housing on stream.
CAUTION:
Failure to bleed the filter housing adequately will
increase the dissolved air content of the system fluid
which will shorten fluid service life and may cause other
problems in the system.
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. Body assembly is permanently assembled at
the factory: do not attempt to disassemble the head (1), body
tube (2), change-over valve (9) or check valve (10).
5.3
Differential pressure devices actuate when the filter element (8)
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.
CAUTION:
Continued operation of 329 series bypass filters
(valve options A and G), with differential pressure
device actuated, can allow unfiltered flow downstream.
Continued operation of 329 series non-bypass filters
(valve options W or N) may cause collapse or premature
fatigue failure of the plugged filter element, which could
allow contaminant and unfiltered flow downstream.
Refer to element change instructions in section 7.
5.5
Make sure element change labels are clean and undamaged.
Replace illegible labels with the appropriate new labels.
UR329 Series
s e r v i c e i n s t r u c t i o n s
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 27 °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.
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 the pre-set value, continuity
returns to 'C' - 'A'.
Figure 1 - Switch Circuit Diagram
A
or white
or tag 1
B
or red
or tag 3
3
LOW DIFFERENTIAL PRESSURE
C or black or tag 2
HIGH DIFFERENTIAL PRESSURE