Form RZ-NA-I-FT, Page 18
27. Venter Motor
Remove dirt and grease from the motor housing. Power venter motor
is permanently lubricated.
The integrated circuit board controls and monitors operation of the
venter motor. If the contacts fail to close the venter motor will not run.
If the contacts fail to open, the venter motor will not shut off, prevent-
ing the combustion air pressure switch from opening.
28. Operating Gas Valve
The gas valve requires no field maintenance except careful removal
of external dirt accumulation and checking of wiring connections. In-
structions for testing pressure settings are in Paragraph 12.
WARNING: The operating valve is the prime safety
shutoff. All gas supply lines must be free of dirt or
scale before connecting to the unit to ensure positive
closure. See Hazard Levels, page 1.
29. Limit Control
I
f it is determined that the limit control needs replacing, use only a
factory-authorized replacement part that is designed for the size of
heater. To access the limit control on Sizes 30-75, remove the louver
assembly from the front of the heater. On Sizes 100-300, the limit
control is accessible in the control compartment.
Sizes 250 and 300 have an auxiliary limit control. To access the addi-
tional limit on Size 250 and 300 heaters, remove the fan guard.
For approximate limit locations, see Figure 12, page 15.
30. Combustion Air Pressure
Switch
See Figure 12, page 15, for location. If it is determined that the pres-
sure switch needs replacing, use only the factory-authorized replace-
ment part that is designed for the size of heater being serviced.
31. Flame Rollout Switch
Models FT 30, 45 and 60 are equipped with a flame rollout safety
switch. The flame rollout switch is a temperature activated manually
reset, limit switch. The switch is mounted on the side of the burner
box in a location that senses temperature in a central horizontal loca-
tion at the rear of the burner assembly.
If the flame rollout switch activates to shutdown the heater, the cause
must be corrected.
If it is determined that the flame rollout switch needs replacing, use
only the factory-authorized replacement part that is designed for use
on this heater.
32. Vent System
Check the vent system at least once a year. Inspection should include
all joints, seams, and the vent cap. Replace any defective parts.
