Publication: MAN3002G MAC Equipment, Inc. 18
TROUBLESHOOTING
The items listed below are intended as a quick reference for common
problems that may be encountered with a dust filter. If you are
experiencing any difficulties not covered or have any questions
concerning your MAC filter, contact your local MAC representative or
MAC Equipment, Inc.
POSSIBLE CAUSE SOLUTION
1. High differential
pressure across
tube sheet. (5” H
2
O
and rising)
a) Clogged, kinked,
damaged, or
deteriorated
gauge lines.
Clean or replace lines. If installation is
several years old replacement of lines
may be necessary.
Check internal filter on differential
pressure port on filter housing.
Replace if blocked.
b) Bad gauge.
Normally the gauge will fluctuate
during cleaning pulse. If needle does
not move replace the gauge.
c) Cleaning
mechanism not
working.
Listen to filter for the distinct cleaning
pulse. If it is not present:
Check timer for proper functioning.
(Refer to start-up instructions.)
Check air supply pressure at
header (should be 80-100 psig).
Check solenoid and diaphragm
valve operation. Check for loose
wiring or dirt in the valves.
Check for moisture or oil in air
lines.
d) Bags blinding.
Inspect bag dust cake. High humidity
and condensation will cause dust
cakes that are difficult to remove. Run
filter with exhaust fan off and without
dust load for 15 to 30 minutes until
cake is removed.
Preheat filter on start up to avoid
condensation. If air stream is
extremely humid then review
application with MAC Equipment, Inc.
If condensation is a recurring problem,
start and operate the system with no
dust load until the filter reaches
ambient temperature. It may also be
necessary to operate the system with
no dust load for a time at shut down.
e) Hopper
overloading.
Check discharge mechanism for
proper operation. Do not use the
hopper for storage of material unless
the collector has been designed for
this function.
Check for material bridging across
hopper. Coat hopper with Teflon type
material or add a properly sized
vibrator to keep hopper clear.
f) System air
volume too high.
Check air flow of system and compare
with design values. If air flow is too
high review application with MAC
Equipment, Inc.
g) Dust particle size
too small.
Small particles (less than 10 microns)
will affect efficiency of filter media.
Analyze particle size distribution with
original design parameters. If
excessive amounts of small particles
are present then review application
with MAC Equipment, Inc.
h) Bags fit on cages
too tightly.
Check bag fit on cages with the pinch
test. You should be able to pinch ½"
of fabric at any position. Tight bags
will not allow the bags to 'flex' properly
for cleaning. If bags are too tight
replace them. Bags which have been
cleaned or washed may shrink and
must be checked for proper fit on
cage.
2. Low differential
pressure drop. (less
than 1/2” H
2
O)
a) Check items 1a
and 1b.
b) Holes in bags.
Replace worn bags
c) Incorrect bag
installation
causing leakage.
Look for dust in clean air plenum.
Refer to bag installation procedure.
3. Dust in exhaust air.
a) Normal for start
up period with
new bags.
Allow filter to run with a dust load for
48 to 96 hours.
b) Check items 2b
and 2c.
c) Over-cleaning of
bags.
Increase the "Time off" setting on the
timer board.
If a photohelic gauge is in use,
increase “high” setting on the gauge.
4. Poor bag life.
a) Incorrect filter
media.
High temperatures, chemical content,
and dust composition will affect bag
life.
b) Abrasion
Poor inlet design practices such as
high inlet velocities and elbows on the
inlet can cause accelerated abrasion
on bags. Consult MAC Equipment,
Inc. for guidance.
c) Damaged cages
Damaged, corroded or bent cages can
wear on bags. Replace cages.
Coated or stainless steel cages are
available.
d) Moisture in air
stream.
Moisture will cause acids to form in
some applications which weaken the
filter media. Check moisture level and
composition of dust and air stream.
Consult MAC Equipment, Inc. for
review of application.
e) Excessive air to
cloth ratio.
Check air to cloth ratio and compare to
original specifications.
f) Improper cleaning.
Review cleaning procedures.
Improper cleaning can shorten bag life.
Disconnect and properly lockout
electrical and compressed air service before
performing any maintenance or service
procedures on the filter.
It is imperative that the timer control panel
enclosure be secured at all times unless access
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