MagnaTherm Boilers and Water Heaters
Page 83
After the valve has been removed, reassemble in
reverse order making sure to include all gaskets
and O-rings. Turn on the manual gas valves and
check for gas leaks. Turn on the main power. Place
the unit in operation following the instructions in
Section 10. Once the boiler is operating, check for
leaks again and confirm all fasteners are tight.
Check the setup for the unit according to the
instructions in Section 9.
11.B.3 Controller
Each unit has an integrated controller that
incorporates manual reset high limit control,
operating temperature control, modulating control,
ignition control, outdoor reset control, pump control
and many other features. If any of these features
are thought to be defective, please consult the
factory for proper troubleshooting practices before
replacing a control.
If it is necessary to replace a controller, turn off
all power to the unit and shut off all manual gas
valves to the unit. Open the front doors to the
unit. Remove all wire connections from the control
board. The control board connections are keyed
to only allow connection in the proper location, but
proper handling techniques should be used to avoid
damage to the wiring or connectors. To remove the
control, undo the mounting screws. To replace the
control repeat the steps listed above in the reverse
order making sure to connect all wires in the proper
locations. Place the unit in operation following the
steps outlined in Section 10.
11.B.4 Spark Ignition Electrodes
The spark ignition electrode is a dual rod assembly.
The ground rod is fastened to the mounting bracket
of spark electrode assembly. The spark electrode
passes through a ceramic insulator and then aligns
with the ground rod. In order for a proper spark to
form, the mounting bracket must be grounded to
the boiler chassis. To remove the spark ignition
electrodes shut off the power to the unit, turn off
the main gas supply and open the front door of the
boiler to gain access to the top portion of the unit.
Remove the high tension ignition wire from the
spark electrode. Remove the two nuts and spacer
holding the spark electrode assembly in place. Pull
the spark ignition electrodes out of the boiler slowly
making sure to move the assembly as need, so the
electrodes are not bent as they are being removed.
If the old assembly is determined to be defective,
install a new spark assembly in the reverse order,
replacing the gasket if necessary.
11.B.5 Flame Sensor
The flame sensor is a single rod system. The minimum
flame signal that will allow the unit to fire is 0.8 volts. To
replace the flame sensor electrode, shut off the power
supply to the boiler. Turn off all manual gas valves
connecting the boiler to the main gas supply line. Open
the front doors of the boiler to gain access to the flame
sensor electrode. Remove the flame sensor wire from
the electrode. Remove the two nuts fastening the
electrode to the burner plate. Remove and replace
the old flame sensor gasket. If the old electrode is
determined to be defective, reinstall a new flame
sensor electrode in the reverse order.
CAUTION
The igniters and sensors can become very hot.
If you touch these parts accidentally, this can
cause burns or injury.
11.B.6 Blower 1600
The combustion air blower is a high pressure centrifugal
blower with a variable speed motor. The blower is driven
by the control system using a PWM signal.
If it is necessary to service, remove or replace the
blower, the Main Power MUST be disconnected and
the main gas supply to the unit must be turned off.
Open the doors and remove the doors from their
hinges. Remove the top and top side jacket panels.
Remove the fasteners holding the fuel/air mixer to the
blower inlet. Remove the hardware that is connecting
the blower outlet to the unit’s adapter plate. If the
blower is determined to be defective, replace the
existing blower with a new one and assemble in the
reverse order. Be sure to install all of the required
gaskets and O-rings between the blower adapter plate
and air/fuel mixer.
11.B.7 Blower 2000-4000
The combustion air blower is a high pressure
centrifugal blower with a variable speed motor driven
by a factory installed VFD located in the high voltage
box. The speed of the motor is determined by the
controls logic which is delivered to the VFD by a
0-10VDC signal.
If it is necessary to service, remove or replace the
blower, the Main Power MUST be disconnected and
the main gas supply to the unit must be turned off. To
replace or remove the blower, turn off main power,
remove hardware that connects the Fuel/Air mixer to
the blower, then remove the hardware that connects
the blower to the adapter plate. If the fan is
determined to be defective, replace the existing fan
with a new one by reversing the steps listed above.
Be sure to install all the required gaskets and o-rings
between blower, adapter plate, and Fuel/Air mixer.
