Cleaning Heat Exchangers - International comfort products F9MXT0401410A Service And Technical Support Manual

SERVICE AND TECHNICAL SUPPORT MANUAL
11. Run the furnace through two complete heating cycles to
check for proper operation
12. Install control door when complete.
Checking Heat Pad Operation (If Applicable)
In applications where the ambient temperature around the
furnace is 32_F (0_C) or lower, freeze protection measures are
required. If this application is where heat tape has been
applied, check to ensure it will operate when low temperatures
are present.
NOTE: The Heat Pad, when used, should be wrapped around
the condensate drain trap. There is no need to use heat tape
within the furnace casing. Most heat tapes are temperature
activated, and it is not practical to verify the actual heating of
the tape. Check the following:
1. Check for signs of physical damage to heat tape such as
nicks, cuts, abrasions, gnawing by animals, etc.
2. Check for discolored heat tape insulation. If any damage
or discolored insulation is evident, replace heat tape.
3. Check that heat tape power supply circuit is on.

Cleaning Heat Exchangers

The following items must be performed by a qualified service
technician.
Primary Heat Exchangers
If the heat exchangers get an accumulation of light dirt or dust
on the inside, they may be cleaned by the following procedure:
NOTE: If the heat exchangers get a heavy accumulation of
soot and carbon, both the primary and secondary heat
exchangers should be replaced rather than trying to clean them
thoroughly due to their intricate design. A 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, improper vent
termination, incorrect size or damaged manifold orifice(s),
improper gas, or a restricted heat exchanger (primary or
secondary). Action must be taken to correct the problem.
1. Turn off gas and electrical supplies to furnace.
2. Remove control door.
3. Disconnect wires or connectors to flame rollout switch,
gas valve, igniter, and flame sensor.
4. Using backup wrench, disconnect gas supply pipe from
furnace gas control valve.
5. Remove two screws attaching top filler plate and rotate
upwards to gain access to screws attaching burner
assembly to cell panel.
6. Remove screws attaching burner assembly to cell panel.
(See Figure 9)
NOTE: Burner cover, manifold, gas valve, and burner
assembly should be removed as one assembly.
7. Clean heat exchanger openings with a vacuum and a
soft brush. (See Figure 12)
20
Figure 12
NOTE: After cleaning, inspect the heat exchangers to ensure
they are free of all foreign objects that may restrict flow of
combustion products.
8. Reverse items 6 through 1 for reassembly.
9. Refer to furnace wiring diagram and reconnect wires to
flame rollout switch, gas valve, igniter, and flame sensor.
10. Turn on gas and electrical supplies to furnace.
11. Check furnace operation through two complete heat
operating cycles. Look at burners. Burner flames should
be clear blue, almost transparent. (See Figure 13)
Figure 13
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Never purge a gas line into a combustion chamber.
Never test for gas leaks with an open flame. Use a
commercially
specifically for the detection of leaks to check all
connections. A fire or explosion may result causing
property damage, personal injury or loss of life.
12. Check for gas leaks.
13. Replace main furnace door.
Specifications subject to change without notice.
Gas Furnace: (F/G)9MXT
Cleaning Heat Exchanger Cell
Burner Flame
Burner Flame
Manifold
WARNING
!
available soap solution
Burner
A11461
made
440 04 4321 08