Instruction manual

41
Upright Counterflow Filter Removal
To remove filters from the ductwork above an upright
counterflow installation:
1. Set thermostat to the OFF position or turn OFF electri-
cal power to furnace.
2. Remove access door in ductwork above furnace.
3. Remove filters.
4. Replace filters opposite of removal. Replace access
door in ductwork.
5. Turn ON thermostat or electrical power to furnace.
Horizontal Unit Filter Removal
Filters in horizontal installations are located in the central
return register.
To remove:
1. Set thermostat to the OFF position or turn OFF electri-
cal power to furnace.
2. Remove filter(s) from the central return register.
3. Replace opposite of removal.
4. Turn ON thermostat or electrical power to furnace.
BURNERS
Visually inspect the burner flames periodically during the
heating season. Turn on the furnace at the thermostat and
allow several minutes for flames to stabilize, since any
dislodged dust will alter the flames normal appearance.
Flames should be stable, quiet, soft, and blue (dust may
cause orange tips but they must not be yellow). They
should extend directly outward from the burners without
curling, floating, or lifting off. Flames must not impinge on
the sides of the heat exchanger firing tubes.
INDUCED DRAFT AND CIRCULATOR BLOWERS
The bearings in the induced draft blower and circulator
blower motors are permanently lubricated by the manufac-
turer. No further lubrication is required. Check motor
windings for accumulation of dust which may cause over-
heating. Clean as necessary.
CONDENSATE TRAP AND DRAIN SYSTEM
(QUALIFIED SERVICER ONLY)
Annually inspect the drain tubes, drain trap, and field-
supplied 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 in-
spected at the beginning of each heating season. If
necessary, clean the passageways as outlined below.
1. Turn OFF the electrical power and gas supply to the
furnace.
2. Disconnect the gas line and remove the burner/ mani-
fold assembly by removing the screws securing the
assembly to the partition panel.
3. Disconnect the flue pipe system from the induced draft
blower.
4. Remove the induced draft blower and, drain and
pressure tap hoses from the recuperator coil front
cover.
5. Remove the recuperator coil front cover to expose the
coil tubes and turbulators.
6. Remove the recuperator coil turbulators individually
by slowly pulling each turbulator forward firmly.
7. Clean the recuperator coil tubes using a long handle
wire brush, such as a gun cleaning brush.
8. Clean the primary heat exchanger tubes using a wire
brush attached to a length of high grade stainless steel
cable, such as drain cleanout cable. Attach a variable
speed reversible drill to the other end of the cable.
Slowly rotate the cable with the drill and insert it into
one of the heat exchanger tubes. While reversing the
drill, work the cable in and out several times to obtain
sufficient cleaning. Repeat for each tube.
9. Clean residue from furnace using a vacuum cleaner.
10. Replace the parts removed in the previous steps in
reverse order.
11. Turn on electrical power and gas to furnace. Check for
leaks and proper unit operation.
12. Severe heat exchanger fouling is an indication of an
operational problem. Perform the checks listed in
Section XIV, Startup Procedure and Adjustments to
reduce the chances of repeated fouling.