User’s Information Manual
8
441 02 2001 06
Unit Maintenance
Have your unit inspected and serviced on an annual basis (before
the heating season) by a qualified service technician.
Labeling
CAUTION
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and dan-
gerous operation.
Verify proper operation after servicing.
Pressure Switches
During regular yearly maintenance check for cracks in the tubes
on the pressure switches.
Electrical shock hazard.
Turn off electric power to unit before performing
any maintenance or removing panels or doors.
Failure to observe could result in death or bodily
injury.
!
Air Filters/ Monthly
The air filter(s) should be inspected monthly and cleaned or re-
placed as required. There are two types of filters that are common-
ly used. The most widely used is the Fiberglass disposable type
which should be
REPLACED
before it becomes clogged. The oth-
er type is the washable type constructed of aluminum mesh, foam,
or reinforced fibers. Washable filters may be cleaned by soaking in
mild detergent and rinsing with water.
Remember that dirty filters are the most common cause of inade-
quate heating or cooling performance.
Fire hazard from dust and lint buildup on internal
unit parts.
Never operate unit without a filter installed.
Failure to observe could result in death or bodily
injury.
!
Replacement Filters
Table1
lists recommended sizes and types of filters that may be
used with your unit, based on the input rating and Btuh.
Replacement filters should be of the same type and size as the
originals, to ensure adequate air flow and filtering. A disposable
low velocity filter can be replaced with a washable high velocity
type.
Do not replace a high velocity filter with a disposable low ve-
locity filter.
Filter Replacement (Optional Filter Rack) -- Upflow
The filter rack may be installed in the bottom of the blower compart-
ment, or on the outside on either side of the unit. A plastic end cap
is inserted in the filter rack after the filter is installed. The end cap
keeps air from escaping around the open end of the filter rack. See
Figure 5
and
Figure 7
for locations.
Filter racks attached to the unit are made so the filter simply slides
out one side for removal.
1. Turn off electric power to furnace.
2. Remove the end cap from the filter rack.
3. Slide the filter out of the filter rack.
4. Inspect the filter(s) and replace or clean washable types. If
filter is aluminum mesh it should be recoated with filter coat-
ing spray.
5. Reinstall the end cap in the filter rack.
6. Turn furnace on.
Filter Replacement -- Bottom Mounted
1. Turn off power to furnace.
2. Remove blower door.
3. Slide filter straight out toward you.
4. Inspect the filter(s) and replace or clean washable types. If
filter is aluminum mesh it should be recoated with filter coat-
ing spray.
5. Replace blower door.
6. Turn on electric power to furnace.
Side Mounted Filter Rack
FH3180A
Figure 5
Filter Replacement -- Counterflow
A filter rack is supplied with all downflow models, however fil-
ters are not supplied with all models. (see to
Figure 6
) Refer to
note for proper size. The filter rack is installed in the top of the
counterflow unit from the right side. To remove filter, refer
to
Figure 6
for the following steps.
NOTE:
The filter rack on all downflows require two(2) 16
²
x 18
²
cleanable high velocity filters. On furnaces with airflow below
1200 cfm a disposable filter can be used.
