5165698-UUM-A-1215
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Johnson Controls Unitary Products
SECTION IV: FURNACE MAINTENANCE -
USER INFORMATION
EXTERNAL AIR FILTERS
Filters used with this furnace must be installed external to the furnace
casing. DO NOT attempt to install filters inside the furnace cabinet.
Some installations may have the air filter in a rack attached to the cas-
ing of the furnace or placed in the return air duct. If the filter location or
replacement process is not obvious, contact your installer or service
technician for assistance.
Every time the external air filters are changed the following items should
be visually inspected:
• Check combustion air and vent pipe for blockage or leakage.
• Check all components to be sure they are in good condition and
that there are no obvious signs of deterioration.
• Check the drain lines to make sure there are no cracks or leaks.
• Check for dirt or lint on any surfaces or on components. Do not try
to clean any of the surfaces or components. Cleaning of the fur-
nace and its components must be done by a qualified service pro-
fessional.
If during the inspection of your furnace, you find any of the following
conditions:
• Excessive amounts of dust and lint on components.
• Damaged or deteriorated components or surfaces.
• Leaks or blockage in the vent pipe passages.
• Water on any surface inside or outside of the furnace.
Do not operate the furnace, call a certified dealer or servicing contractor
to check or clean your furnace, or for more information if you have
questions about the operation of your furnace.
If all components appear to be in good operating condition, replace the
furnace access panels/doors. Turn ON the gas and electrical power
supplies to the furnace, and set thermostat to the desired temperature.
How to Clean your Filter
High-velocity filters may be cleaned with a vacuum cleaner or washed
with a garden hose. Be sure to shake off excess water and allow filter to
completely dry before re-installing the filter.
Replace throw away filter(s) with the same size new filter(s). Throw
away filter(s) may be replaced with cleanable filter(s) at this time.
Removing Filters For Manufactured (Mobile) Home And
Modular Home Installations Using A Return Air Duct Sys-
tem And Plenum
Modular Home downflow furnaces requiring a return duct system by
Local, State, or Regional Codes will have the filters located on the top of
the furnace in an external filter rack located inside the return air plenum
as shown in Figure 5. To check, clean or replace the air filters you
should:
1. Follow the instructions to turn off the appliance before servicing.
2. Filters that are installed in the return air plenum above the blower
assembly and are located in an “V” frame assembly that supports
the filters as shown in Figure 5.
3. To remove the filters you must remove the screws that are securing
the access panels on the return air plenum and remove the access
panels.
4. Lift the filters lightly and remove them.
5. If the filters are the throw away type you must replace the filters with
filters that are the same size as the filters you removed. If you want
to replace the throwaway air filters with permanent washable filters
you can do so at this time.
6. If the filters are washable, follow the instructions “HOW TO CLEAN
YOUR FURNACE’S FILTER”.
7. To reinstall the air filters reverse steps 1 – 6 above.
8. To place the furnace back in operation follow the operating instruc-
tions to place appliance in operation.
Removing Filters For Manufactured (Mobile) Home And
Modular Home Installations Without A Return Air Duct Sys-
tem And Plenum
Manufactured (Mobile) Home downflow furnaces and modular home
furnaces not requiring a return duct system by Local, State, or Regional
codes will have the filters located on the top of the furnace in an exter-
nal filter rack. To check, clean or replace the air filters you should:
1. Follow the instructions to turn off the appliance before servicing
2. Filters that are installed on the top of the furnace above the blower
assembly and are located in an “A” frame assembly that supports
the filters as shown in Figure 5.
3. To remove the filters just slide them out of the assembly. You may
have to bend the filters to slide them around the combustion air and
the vent pipes.
4. If the filters are the throw away type you must replace the filters with
filters that are the same size as the filters you removed. If you want
to replace the throwaway air filters with permanent washable filters
you can do so at this time.
5. If the filters are washable, follow the instructions “HOW TO CLEAN
YOUR FILTER”.
6. To reinstall the air filters reverse steps 1 – 4 above.
7. To place the furnace back in operation follow the operating instruc-
tions to place appliance in operation.
WARNING
Before proceeding, be sure the area is well ventilated. Turn the ther-
mostat OFF. If the blower is running, wait until it stops automatically.
Turn OFF the gas and electrical power supplies to the furnace. Check
all metal parts and surfaces to be sure they have cooled to room tem-
perature before you begin.
!
FIGURE 5:
Mobile Home Filter Frame
