Nortek Reznor VRA-4E Series, Installation, Commissioning, Servicing

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1712VRA ‐ 4EGBEN, pag.. 16/25
8.3 Ignition system
To access the ignition system, follow steps 1 to 3 in
§ 8.1.
ATTENTION :
Due to high voltage on the spark
wire and electrode, do not touch when energized.
See hazard levels.
Ignitor - refer to figure 9 and locate the ignitor (on
the side of the burner rack). Disconnect the wire,
remove the screw and the ignitor. Clean with an
emery cloth.
Note: Spark gap must be maintained to 3.0 mm (see
figure 10a). Re-fit the ignitor as per figure 10b.
Flame sensor - Refer to figure 9 and locate the
flame sensor. Disconnect the wire, remove the screw
and the flame sensor. Clean with an emery cloth.
Ignition controller -
The enclosed integrated circuit
monitors the operation of the burner including
ignition. Do not attempt to dismantle the ignition
controller. Each heating season ignition cables
should be checked for insulation deterioration and
good connections.
Proper operation of the direct spark ignition
system requires a minimum flame current of 1,0
μ A when measured with a micro-ammeter.
Fig. 10a - Ignitor assembly
For further information and checkout procedure of the direct
spark ignition system, refer to the manufacturers control
operating instructions a copy of which is supplied with the air
heater.
Fig. 10b -: Fitting the ignitor
8.4 Multi-functional gas control valve
1. Ensure gas supply to the air heater is turned
OFF.
2. After the air circulation fan has stopped, switch
OFF the electricity supply to the air heater.
3. Mark for future identification and disconnect the
wires connected to the valve.
4. Disconnect the gas service union between the
control valve and the gas service tap. Remove
the gas control valve.
5. Re-fit a replacement valve making all of the
required connections.
6 Carry out complete commissioning procedure
prior to placing the appliance back into service
as outlined in section 6.0.
ATTENTION : The gas control operating valve is the
prime safety shut-off. All gas supply lines must be free of
dirt, scale,
etc. before connecting to the air heater thus ensuring
positive closure of the control valve.
8.5 Combustion air control/switch
If it is determined that the air differential pressure
switch needs replacing, use only authorized
replacements that are designed for the air heater
being serviced. These switches are calibrated to
operate at the designed combustion air flow duty for
each appliance size in the product range.
8.6 Combustion air fan (venter)
(The combustion air fan motor is lubricated for life.
Do not oil or grease.)
1. Ensure gas supply to the air heater is turned OFF
2. After the air circulation fan has stopped, switch
OFF the electricity supply to the air heater.
3. To gain access to the fan open the hinged controls
compartment access door. Refer to figure 9 for
location
4. Mark for future identification and disconnect the
wires connecting the fan motor at the terminals on
the main wiring junction.
5. Remove combustion air fan and clean as
necessary using a wire brush and solvent to
remove sticky residues.
6. Re-assemble and check for free rotation before
proceeding to test the appliance.
8.7 Thermal overheat (limit) controls
If it is determined that the thermal overheat control
needs replacing, use only authorized replacements
that are designed for this appliance. To gain access
to the control, open the controls compartment access
door. Refer to figure 9 for control locations. The
control near the top of the air heater is a disc type
control. Both controls are capillary types with a
capillary tube that extends into the heat exchanger
area. To remove the controls, disconnect the wires
leading to them, remove the fixing screws and lift
clear of the inner casing panel. When replacing a
capillary control be careful not to damage the
capillary tube by kinking. Make bends with a generous
radius (approx 25 mm).
Note: The capillary control is fitted to a bracket. With
the bracket removed from the heater, remove the
control from the bracket.