International comfort products R9MSB Service And Technical Support Manual page 20

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.
WARNING
!
ELECTRICAL SHOCK, FIRE OR EXPLOSION
HAZARD
Failure to follow this warning could result in personal
injury or death, or property damage.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF
position and install a lockout tag. There may be more
than one disconnect switch. Lock out and tag switch
with a suitable warning label. Verify proper operation
after servicing.
WARNING
!
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Turn off the gas and electrical supplies to the furnace
and install lockout tag before performing any
maintenance or service.
instructions on the label attached to the 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 14.)
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 11.)
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 2 complete heat
operating cycles. Look at burners. Burner flames
should be clear blue, almost transparent. (See
Figure 12.)
12. Check for gas leaks.
20
Follow the operating
Specifications subject to change without notice.
WARNING
!
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 available
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.
13. Replace main furnace door.
Secondary Heat Exchangers
The condensing side (inside) of the secondary heat
exchanger CANNOT be serviced or inspected without
complete removal of the heat exchanger assembly. Detailed
information on heat exchanger removal can be obtained
from your Distributor.
WINTERIZATION
CAUTION
!
UNIT AND PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in unit
component or property damage.
If the furnace is installed in an unconditioned space
where the ambient temperatures may be 32_ F (0_ C) or
lower, freeze protection measures must be taken to
prevent minor property or product damage.
Since the furnace uses a condensing heat exchanger, some
water will accumulate in the unit as a result of the heat
transfer process. Therefore, once it has been operated, it
cannot be turned off and left off for an extended period of
time when temperatures will reach 32_F (0_C) or lower
unless winterized. Follow these procedures to winterize your
furnace:
CAUTION
!
UNIT COMPONENT DAMAGE HAZARD
Failure to follow this caution may result in damage to the
furnace and other property damage.
Do not use ethylene glycol (automotive antifreeze
coolant or equivalent). Failure of plastic components
may occur.
1. Obtain propylene
antifreeze or equivalent).
2. Turn off gas and electrical supplies to your furnace.
3. Remove furnace control door.
4. Remove the top unused rubber plug from the port on
the collector box opposite the condensate trap. See
Figure 10.
5. Connect a field supplied 3/8−in. (9.5−mm) ID tube to
the open port on the collector box.
6. Insert a field supplied funnel into the tube.
7. Pour 1 quart of anti−freeze solution into the funnel/
tube. Antifreeze should run through the inducer
housing, overfill condensate trap and flow to an open
drain.
8. Replace the rubber plug in the port on the collector
box.
9. Remove the middle unused rubber plug from the port
on the collector box opposite the condensate trap.
See Figure 10.
10. Repeat Steps 5 through 8.
soap solution made
glycol (RV/swimming pool
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