Labconco Type C1 Biosafety Cabinet Models 30468 - Manual (Page 20)

Product Service 1-800-522-7658 20
The filter life gauge calculates the remaining filter life by measuring and comparing
the current motor speed to the initial speed noted at the factory during assembly,
and the calculated maximum motor speed, using the formula:
100-(100x (current speed-original speed) ) = % filter life left
max. speed-original speed
So
anything that changes the motor’s current speed, like:
 Blocking the grille.
 Raising the air temperature.
 Lowering the barometric pressure.
will increase the motor’s speed, causing the Filter Life Gauge to decrease. Electronic
dampening of the gauge will limit the change in readings to approximately
1%/minute.
Axiom Biosafety Cabinets being installed at altitudes or operating at temperatures
significantly different from those at the time of manufacture (900 +/- 500 ft above
sea level, 75 o +/- 5 o F) must have their filter life gauge recalibrated for local
conditions. Failure to do so will result in the users noticing a steady drop in Percent
(%) Filter Life remaining as the unit operates. Below are the instructions on how to
correct the Filter Life Gauge for local conditions.
1. Ensure to correct all measurement equipment for local conditions
(temperature, absolute pressure). Anemometers may not have this
ability and might have to be done manually; whereas, a
ShortRidge
TM instrument has a setting to correct for local conditions.
2. As the elevation or the ambient temperature rises, the motor power
factor will have to be reduced to compensate. For an initial
certification, the motor speed should be reduced until it equals the
Axiom’s “Initial Motor Speed” as reported on the unit’s test sheet,
plus approximately 10-15 RPM per each additional 1000 feet of
elevation.
3. The Axiom MUST be recertified using instruments corrected for local
conditions.
4. When the unit is recertified, and operating properly, the certifier
MUST RESET THE FILTER LIFE GAUGE, INDICATING A NEW FILTER
HAS BEEN INSTALLED.
5. Only by performing Step #4 AFTER THE UNIT IS READJUSTED AND
RECERTIFIED FOR ITS LOCAL CONDITION, will the filter life gauge
register 100% (+/- 2%) during operation. As the Filters then load,
the filter life gauge will then begin to drop as appropriate.