Air Filters
The air filter section is an integral part of the environmental control system, designed within the unit for easy front
and/or side accessibility. An initial set of filters are factory installed in the unit. The filters are 2-inch deep for ceiling
units or 4-inch deep for floor units unless otherwise specified, disposable, pleated design, extended-surface,
nonwoven, reinforced cotton fabric; enclosed in cardboard frame design rated not less than MERV 8 per ASHRAE
Std. 52.2. A filter differential switch for alarm activation is included on some units and optional on other units. Air
filters should be checked on a regular basis and changed when they become dirty. This will ensure efficient
operation of the unit. Air filters that that are not maintained and require changing can restrict airflow and create
problems such as coil icing or poor air distribution. Spare air filters should be kept in stock as these tend to be a
frequently replaced maintenance item. Air filters may require changing as often as monthly dependent on room or
space conditions.
On some units, the dap4 controller monitors the air filters status and a dirty filter alarm will be enunciated on the
display and available as a Building Management System (BMS) data port. Although the unit may display a dirty filter
alarm, this should not be relied on as the only determinant for replacing air filters. A misadjusted air filter differential
pressure switch may not give a proper indication of a clogged filter.
To check the air filter pressure differential pressure switch for proper adjustment, temporarily cover approximately
75% of the return air opening using heavy cardboard or similar material. The alarm should energize when 75% of
the air is blocked, simulating dirty filters. If the alarm energizes prematurely or does not energize at all, the pressure
switch should be adjusted. All side panels must remain closed when determining if an adjustment is necessary.
In general, the filters are removable from the front of the unit on Data Aire gPod floor units, unless otherwise
specified. gPod ceiling mounted unit filters are removable from the side, unless otherwise specified.
7.6.1 Upflow Unit Air Filter Replacement Procedure
1. Turn OFF all electrical input power to the floor unit with the external disconnect.
2. Open the front access door(s) and remove the filters by lifting them up and maneuvering the filter
downward and out of the unit.
3. Replace with new filters of equal size and type. Install the filters in the proper direction of the airflow. New
filters must be U.L. and CSA approved.
4. Test the operation of the filter differential pressure switch. The unit door(s) must be in place and closed to
determine the proper differential pressure setpoint.
5. Turn ON the electrical input power to the unit which will start the blower(s) and temporarily cover
approximately 75% of the return air opening using heavy cardboard or similar material to cause the filter
differential switch to alarm. Adjust the switch setpoint, if necessary.
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