by removing the burner assembly. Th
e bottom row is only acces-
sible if the heat exchanger is removed and the rear fl ue box cover
is removed. Th
e recovery coil (secondary heat exchanger) may be
cleaned by accessing the rear fl ue box cover or removing the front
manifold cover. Aft er clearing accumulated scale, observe the burner
fl ames. If there appears to be fl ame distortion, check the combustion air
intake and exhaust piping and terminals for blockage. Also check for
signs of soot in the condensate drainage. If fl ame distortion continues
aft er eliminating the blockage in the piping as the cause, it may be
necessary to replace the tubular heat exchanger.
NOTICE
NOTE: Prior to removal of rear fl ue box cover or front
manifold cover, ensure that replacement gaskets are avail-
able to ensure proper sealing of the heat exchanger when
re-assembled.
BURNERS -
Th
e burners should be inspected to ensure that they
are free of deterioration, dust and debris, and properly aligned with
the heat exchanger. In most cases, a simple vacuuming with a brush
attachment will adequately clean the burner assembly and burner
compartment.
!
CAUTION
Be careful when working on the burner assembly. Th
e hot
surface igniter is fragile and can break easily.
Th
e fl ame sensor should be inspected and cleaned with fi ne steel
wool or Scotch-Brite™ scrubbing pad. Th
e wiring connection should
be checked to ensure that it is tight and corrosion free.
24 - MAINTENANCE AND TROUBLESHOOTING
NOTICE
NOTE: Th
is is a critical connection. Small amounts of
corrosion can signifi cantly increase the internal resistance
of the connection. A relatively small increase in resistance
can result in a large decrease in fl ame signal.
DRAINAGE
-
Th
e condensate drainage system should be inspected
and cleaned if necessary. If the drain trap assembly, or any other
component becomes blocked, condensate may backup into the
secondary or primary heat exchanger causing nuisance trip-outs
of the pressure switches or limit switch. Th
e condensate should be
observed for signs of dirt, carbon, debris, etc.
If a condensate neutralizer has been added to the condensate drain,
it should be inspected, cleaned, or the condensate neutralizing media
should be replaced to ensure clear condensate fl ow.
INDUCED BLOWER
-
Th
e induced blower motor should be
inspected and cleaned if necessary. Clear any dust buildup from the
ventilation ports.
CIRCULATING FAN
-
Th
e condition of the circulating fan should
be checked to ensure that it is free of excessive dust buildup, debris,
etc. Th
e mechanical fasteners should be inspected and checked for
proper tightness and parts alignment. Th
e motor ventilation ports
should be cleaned if necessary to prevent restriction to cooling by air
over the motor.
ELECTRICAL
-
All electrical connections should be examined to
ensure that they are tight and corrosion free. Repair any connections
that have become loose or corroded.
FURNACE OPERATION
-
Th
e furnace should be cycled during the
annual inspection and servicing to:
1.
Test all safety related controls.
2.
Determine that the temperature rise falls within the range
shown on the appliance rating plate.
3.
Ensure that the burner ignition is smooth and that the fl ames
are smooth soft blue, and not impinging on the heat exchanger.
49
