Despatch LCC/LCD2-14-3 Non Pass Through Series - Manual (Page 29)

20
HEPA Filter / Magnehelic Pressure Gauge
The LCC Series oven is equipped with a Magnehelic pressure gauge which measures
the pressure in front of the HEPA filter. As the filter becomes dirty, the pressure will
increase. Despatch recommends changing the filter when the pressure is 1” w.c.
greater than when the filter was first installed.
Since the pressure can be affected by many factors involved in the installation, it is
important to record the pressure of a new filter, so that the pressure readings can be
periodically checked against this baseline. The table below is provided for recording
this information.
HEPA Filter Preventative Maintenance Table
A B C D E F
Date Comments Pressure with
350 SCFH
nitrogen purge Pressure with
220 SCFH
nitrogen
maintain Pressure
(inches of
water) Oven
Temperature
Typical Values 1.5- 2.5” above
value in column E
0.3- 0.8” above
value in column E
2-3 inches 60°C
Filter first installed.