FURNACE USER MAINTENANCE
Before proceeding, be sure the area is well ventilated. Turn the thermostat 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 temperature before you begin.
Blower Care
Even with good filters properly in place, blower wheels and motors will become dust laden after long months of operation. The entire blower assembly should be inspected annually. If the motor and wheel are heavily coated with dust, they can be brushed and cleaned with a vac- uum cleaner. If the blower cannot be properly cleaned without removing it from the furnace, then this service must be performed by a qualified service agency.
The blower can be serviced/removed through the blower access panel on the inside of the furnace. If there is a combustion air pipe installed inside the furnace, it may have to be removed to access the blower access panel. After the combustion air pipe is removed, it is easy to remove the inside blower access panel by removing the screws of the access panel. Blower is now ready to be serviced through the opening. If the blower has to be removed through the inside blower access panel, then the top and bottom angles will have to be removed to slide the blower out of the furnace.
Make sure you DO NOT move the
Air Filters
The filters should be checked every 3 months. On new construction, check the filters every week for the first four weeks and every three weeks after that, especially if the indoor fan is running continuously. When replacing the filter(s), refer to Table 1 to be sure you install the right size filter for your furnace. Dirty filters greatly restrict the flow of air and may cause damage to the moving parts of the furnace. If the filters become clogged the heat exchangers and blower motor could overheat resulting in a potentially dangerous situation.
Never operate your furnace without a suitable air filter. Use the following procedure to determine the filter size.
1.Measure the furnace width and use that measurement to deter- mine the cabinet width.
•A
•A
•A 21” wide cabinet is a “C” cabinet.
•A
2.Locate the cabinet size on Table 1 then determine whether you have a bottom or side return air duct using the following method.
a.If the return air filter is on the left or right side of the furnace it is a side return
b.If the air filter is on the bottom of the furnace then you have a bottom return.
c.If the air filters are on the bottom and the side of the furnace then you have a bottom and side return. You must replace both air filters. Table 1 will indicate 2 filters by using brackets with the number two (2).
d.If the air filters are on both sides of the furnace then you have a two sided return. You must replace both air filters. Table 1 will indicate 2 filters by using brackets with the number two
(2).
3.After you determine the cabinet size and what return configuration you have, look up the recommended filter size from Table 1.
Removing Filters
Most downflow furnaces have their filters located on the top of the fur- nace in an external filter rack. To check filters you should:
1.Follow the instructions to turn off the appliance before servicing.
2.Filters are installed in the return air plenum above the blower assembly. An “A” frame assembly supports the filters. Lift the filter slightly and remove for service.
3.Follow the instructions “HOW TO CLEAN YOUR FURNACE’S FIL- TER”.
4.Reverse the procedure to reinstall filters.
5.Follow the operating instructions to place appliance in operation.
FILTER RACK
(factory supplied with some furnaces)
| RACK AND FILTERS SECURED | |
| INSIDE BLOWER SECTION | |
| FOR SHIPMENT |
|
| CASING SIZE DIMENSION FH | |
| ||
| ||
| 21” | |
| ||
| NOTE: FILTER ACCESS THROUGH | BRANCH |
| DUCTWORK MUST BE PROVIDED | |
| DUCTS | |
| FOR REMOVAL AND CLEANING | |
|
| |
| FILTERS |
|
| FILTER |
|
DUCTWORK | RACK |
|
FH
CROSS SECTION
FIGURE 7: Filter Rack Assembly and Attachment
Externally Mounted Air Filters
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. You can gain access to the filter by pulling on the door or unscrewing the retaining screw, then slide the filter(s) out of its channel. 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. Cleanable filter(s) may be cleaned as described in the manufacturer instructions or as described below and then
How to Clean your Filter
To replace the filter after cleaning you must do the following:
1.Slide filter into place.
2.Snap the door on or place the door in position and tighten the retaining screws, if provided.
3.Make sure the door is secure to the end of the filter rack.
4.For filter grilles, place the filter into the grilles, close the grille cover and tighten the retaining screw.
Every time the 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.
4 | Unitary Products Group |
