International comfort products R9MSB Service And Technical Support Manual page 18

of light dirt or dust, they may be cleaned by using the
following procedure:
NOTE: Use a back-up wrench on the gas valve to prevent
the valve from rotating on the manifold or damaging the
mounting to the burner assembly.
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.
Refer to Figure 14.
1. Disconnect power at external disconnect, fuse or
circuit breaker.
2. Turn off gas at external shut-off or gas meter.
3. Remove control door and set aside.
4. Turn electric switch on gas valve to OFF.
5. Disconnect the gas pipe from gas valve and remove
pipe from the furnace casing.
6. Remove individual wires from terminals on gas valve.
7. Disconnect Hot Surface Igniter (HSI) wires from HSI.
8. Disconnect Flame Sensor wire from Flame Sensor.
9. Support the manifold and remove the 4 screws that
secure the manifold assembly to the burner assembly
and set aside. Note the location of the green/yellow
wire and ground terminal.
10. Inspect the orifices in the manifold assembly for
blockages or obstructions. Remove orifice and clean
or replace orifice.
11. Remove the four screws that attach the top plate of
the casing to the furnace.
12. Raise top plate up slightly and prop it up with a small
piece of wood or folded cardboard.
13. Support the burner assembly and remove the screws
that attach the burner assembly to the heat
exchanger cell panel.
14. Remove wires from both rollout switches.
15. Slide one--piece burner out of slots on sides of burner
assembly.
16. Remove the flame sensor from the burner assembly.
17. (Optional) Remove the Hot Surface Igniter (HSI) and
bracket from the burner assembly.
18. Check igniter resistance. Nominal resistance is 40 to
70 ohms at room temperature and is stable over the
life of the igniter.
19. Clean burner with a brush and a vacuum.
20. Clean the flame sensor with fine steel wool (0000
grade). Do not use sand paper or emery cloth.
To reinstall burner assembly:
1. Install the Hot Surface Igniter (HSI) and bracket in
burner assembly.
2. Install flame sensor on burner.
3. Align the edges of the one-piece burner with the slots
in the burner assembly and slide the burners forward
until they are fully seated in the burner assembly.
4. Align the orifices in the manifold assembly with the
support rings on the end of the burner.
18
Follow the operating
Specifications subject to change without notice.
5. Insert the orifices in the support rings of the burners.
NOTE: If manifold does not fit flush against the burner, do
not force the manifold on the burner assembly. The burners
are not fully seated forward in the burner assembly. Remove
the manifold and check burner positioning in the burner
assembly assembly before re-installing the manifold.
6. Attach the green/yellow wire and ground terminal to
one of the manifold mounting screws.
7. Install the remaining manifold mounting screws.
8. Check the igniter alignment. See Figure 8, Figure 9
and Figure 14.
9. Attach the wires to the roll-out switches.
10. Align the burner assembly with the openings in the
primary cell inlet panel and attach the burner
assembly to the cell panel.
11. Connect the wire for the flame sensor.
12. Connect the wire for the Hot Surface Igniter.
NOTE: Use propane-resistant pipe dope to prevent leaks.
Do not use Teflon tape.
13. Install the gas pipe to the gas valve.
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.
14. Check for gas leaks with a commercially available
soap solution made specifically for the detection of
leaks.
15. Turn gas on at electric switch on gas valve and at
external shut-off or meter
16. Turn power on at external disconnect, fuse or circuit
breaker.
17. Run the furnace through two complete heating cycles
to check for proper operation
18. Install control door when complete.
Servicing Hot Surface Igniter
The igniter does NOT require annual inspection. Check
igniter resistance before removal.
Figure 9 and Figure 14.
1. Turn off gas and electrical supplies to furnace.
2. Remove control door.
3. Disconnect igniter wire connection.
4. Check igniter resistance. Igniter resistance is affected
by temperature. Only check resistance when the
igniter is at room temperature.
a. Using an ohm meter, check resistance across both
igniter leads in connector.
b. Cold reading should be between 40 ohms and 70
ohms.
5. Remove igniter assembly.
a. Using a 1/4−in. driver, remove the two screws
securing the igniter mounting bracket to the burner
assembly (See Figure 14 .)
b. Carefully withdraw the igniter and bracket assembly
through the front of the burner assembly without
striking the igniter on surrounding parts.
soap solution made
Refer to Figure 8,
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