31
months or as required. When replacing a filter, it must be
replaced with a filter of the same type and size.
Filter Removal
Depending on the installation, differing filter arrangements
can be applied. Filters can be installed in either the central
return register or a side panel external filter rack (upflow only).
A media air filter or electronic air cleaner can be used as an
alternate filter. Follow the filter sizes given in the Recom
-
mended Minimum Filter size table 7 on page 25 to ensure
proper unit performance.
To remove filters from an external filter rack in an upright
upflow installation, follow the directions provided with external
filter rack kit.
Horizontal Unit Filter Removal
Filters in horizontal installations are located in the central return
register or the ductwork near the furnace.
To remove:
1. Turn OFF electrical power to furnace.
2. Remove filter(s) from the central return register or
ductwork.
3. Replace filter(s) by reversing the procedure for removal.
4. Turn ON electrical power to furnace.
Media Air Filter or Electronic Air Cleaner Removal
Follow the manufacturer’s directions for service.
Burner
The Ultra Low NOx furnace uses a premix burner. The burner
box is sealed to achieve safe and reliable operation.
SCREW
SENSOR
GASKET
IGNITOR
GASKET
LIMIT
GASKET
BURNER BOX
Burner Box
Figure 37
Induced Draft and Circulator Blowers
The bearings in the induced draft blower and circulator blower
motors are permanently lubricated by the manufacturer. No
further lubrication is required. Check motor windings for
accumulation of dust which may cause overheating. Clean
as necessary.
Condensate Trap and Drain System (Qualified Ser
-
vicer Only)
Annually inspect the drain tubes, drain trap, and field-sup
-
plied drain line for proper condensate drainage. Check drain
system for hose connection tightness, blockage, and leaks.
Clean or repair as necessary.
Flame Sensor (Qualified Servicer Only)
Under some conditions, the fuel or air supply can create a
nearly invisible coating on the flame sensor. This coating
acts as an insulator causing a drop in the flame sense signal.
If the flame sense signal drops too low the furnace will not
sense flame and will lock out. The flame sensor should be
carefully cleaned by a qualified servicer using emery cloth
or steel wool. Following cleaning, the flame sense signal
should be as indicated in the Specifications Sheet.
Flue Passages (Qualified Servicer Only)
The heat exchanger flue passageways should be inspected
at the beginning of each heating season.
Before Leaving an Installation
•
Cycle the furnace with the thermostat at least three
times. Verify cooling and fan only operation.
•
Review the Owner’s Manual with the homeowner and
discuss proper furnace operation and maintenance.
•
Leave literature packet near furnace.
Repair and Replacement Parts
•
When ordering any of the listed functional parts, be
sure to provide the furnace model, manufacturing, and
serial numbers with the order.
•
Although only functional parts are shown in the parts
list, all sheet metal parts, doors, etc. may be ordered
by description.
•
Parts are available from your distributor.
Functional Parts List-
Gas
Valve
Blower
Motor
Gas Manifold
Blower Wheel
Natural Gas Orifice
Blower Mounting Bracket
Igniter
Blower Cutoff
Flame Sensor
Blower Housing
Burner Temperature Switch
Pressure Switches
Primary Limit Switch
Burner Assembly
Coil Front Cover
Drain Trap
Auxiliary Limit Switch
Burner Box Gasket
Transformer
Integrated Control Module
Door Switch
Pressure Sensor
Induced Draft Blower
