N80ESN/N80ESL(Series A): Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
33
d. Verify blower is rotating in the correct direction.
17. If furnace is operating properly, RELEASE BLOWER ACCESS
DOOR SWITCH. Remove any jumpers or reconnect
any
disconnected thermostat leads. Replace blower access
door.
18. Downflow or horizontal furnaces with vent pipe through
furnace
only:
a. Install and connect short piece of vent pipe inside furnace
to
existing vent.
b. Connect vent connector to vent elbow.
19. Reinstall outer door.
20. Cycle furnace through one complete
heating and cooling cycle.
Verify the furnace temperature rise
as shown in “Adjustments”
Section. Adjust temperature rise as
shown in “Adjustments”
Section. If outdoor temperature is
below 70°F, (21°C) turn off
circuit breaker to outdoor unit before
running furnace in the cooling
cycle. Turn outdoor circuit
breaker on after completing cooling
cycle.
CLEANING HEAT EXCHANGER
The following steps should be performed by a qualified service agency:
NOTE:
If the heat exchangers get a heavy accumulation of soot and
carbon, they should be replaced rather than trying to clean them
thoroughly. A heavy build-up of soot and carbon indicates that a
problem exists which needs to be corrected, such as improper adjustment
of manifold pressure, insufficient or poor quality combustion air,
incorrect size or damaged manifold orifice(s), improper gas, or a
restricted heat exchanger. Action must be taken to correct the problem.
If it becomes necessary to clean the heat exchangers because of dust or
corrosion, proceed as follows:
1. Turn OFF gas and electrical power to furnace.
2. Remove outer access door.
3. Disconnect vent connector from furnace vent elbow.
4. For downflow or horizontal furnace having an internal vent pipe,
remove internal vent pipe within the casing.
5. Disconnect wires to the following components. Mark wires to aid in
reconnection of (be careful when disconnecting wires from
switches because damage may occur):
a. Draft safeguard switch.
b. Inducer motor.
c. Pressure switch(es).
d. Limit over-temperature switch.
e. Gas valve.
f. Hot surface igniter.
g. Flame-sensing electrode.
h. Flame rollout switches.
6. Remove screws that fasten the collector box assembly to the cell
panel. Be careful not to damage the collector box. Inducer assembly
and elbow need not be removed from collector box.
7. Disconnect gas line from gas manifold.
8. Remove the 5 screws that attach the burner assembly to the cell
panel. The gas valve and individual burners need not be removed
from support assembly. Remove NOx baffles if installed.
NOTE:
Be very careful when removing burner assembly to avoid
for correct igniter location.
A05026
Fig. 47 – Igniter Position-Top View
A05025
Fig. 48 – Igniter Position-Side View
NOTE:
The materials needed in item 9 can usually be purchased
at local
hardware stores.
9. Using a field-provided 25-caliber rifle cleaning brush; a 36-in. (914
mm) long, 1/4” (6 mm) diameter steel spring cable; and a variable
speed, reversible electric drill; and a vacuum cleaner, clean cells as
follows:
a. Remove metal screw fitting from wire brush to allow insertion
into cable.
b. Insert the twisted wire end of brush into end of spring cable, and
crimp tight with crimping tool or crimp by striking with
ball-peen hammer. TIGHTNESS IS VERY IMPORTANT.
(1.) Attach variable-speed, reversible drill to the end of
spring
cable (end opposite brush).
(2.) Insert brush end of cable into the outlet opening of cell
and
slowly rotate with drill. DO NOT force cable.
Gradually
insert cable into upper pass of cell (see
).
A91252
Fig. 49 – Cleaning Heat Exchanger Cell
1-7/8
(47.6 mm)
9/32”
7.1mm
5/16”
7.9mm
