1210SHH_AMEN,page 24/29
2.6
Fan motor, fan
The fan motor is equipped with thermal overload
protection of the automatic reset type. Should the motor
fail to run, it may be because of improper voltage
characteristics. Make certain that the correct voltage is
available at the motor.
Remove dirt and grease from the motor and the fan. Use
care when cleaning the fan to prevent imbalance.
12.7 Venter motor & wheel
Figure 30
Remove dirt and
grease from the motor
casing, the venter
housing, and the
venter wheel. Venter
motor bearings are
permanently lubri-
cated. Follow these
instructions for re-
placement of the
venter motor and
wheel assembly. Keep all hardware removed to be
used in reassembling and installing the replacement
parts.
1.
Turn off the gas and disconnect the electric power.
2.
Open the control compartment access door.
3. Disconnect the three venter motor wires at the
terminal and ground screw .
4. Holding the motor, remove the screws that attach
the motor plate to the venter housing. Remove the
motor and wheel assembly from the heater.
5.
Reassemble with the replacement venter motor and
wheel assembly.
6. Follow the wiring diagram to properly connect the
wires.
7. Restore power to the heater and turn on the gas.
Light, following the instructions on the lighting
instruction plate. Check for proper operation. Close
the access door.
12.8 Operating gas valve
See figure 31
The main operating
quick opening gas
valve is powered
through the
thermostat and safety
controls. The main
control valve is of the
diaphragm type
providing regulated
gas flow and is
adjusted at the
factory. The gas valve
requires no field maintenance except careful removal of
external dirt accumulation and checking of wiring
connections. Instructions for testing pressure settings
are in sections 9 and 10.
12.9 Combustion air pressure switch
Safe operation of this unit requires proper
venting flow. Never bypass the
combustion air pressure switch or attempt
to operate the unit without the venter
opera ting.
The combustion air pressure switch ensures that proper
combustion airflow is available. The switch senses the
differential pressure between the negative pressure in
the flue gas collector box and the pressure in the control
section. (For switch location, see figure 16). On startup
when the heater is cold, the sensing pressure is at the
most negative level, and as the heater and flue system
warm up, the sensing pressure becomes less negative.
If a restriction or excessive flue pipe length causes the
sensing pressure to be below the allowable level, the
pressure switch will shut off the main burner. If it is
determined that the pressure switch needs replacing,
use only the factory-authorized replacement part that is
designed for the model and size of heater being
serviced.
Figure 32 : pressure switch
055-102: PN 30 60618 420
083:PN 30 60617 300
12.10 Limit controls
Never bypass the limit controls, hazardous
conditions could result
All units are equipped with a temperature activated limit
control. The control is factory set and non-adjustable. If
either set point is reached, the limit control will interrupt
the electric power to the gas valve. This safety device
provides protection in the case of motor failure or lack of
airflow due to restrictions (for location, see figure 16).
Figure 33
