Laars NeoTherm NTH Installation and operation instructions manual - page 31
NeoTherm Boiler
Page 31
10.
Inspect the vent system and air intake system, and
ensure that all joints are sealed properly. If joints
need to be resealed, completely remove existing
sealing material, and clean with alcohol. Apply
new sealing material, and re-assemble.
7.2 Appliance Maintenance and
Component Description
Use only genuine LAARS replacement parts.
Caution
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation. Verify proper operation after
servicing.
The gas and electric controls on the appliance are
engineered for long life and dependable operation, but
the safety of the equipment depends on their proper
functioning. Only a qualified service technician should
inspect the basic items listed below every year:
a. Appliance control
f. Flow switch
b. Automatic gas valve
g. Low water cutoff
c. Pressure switches
h. Burner
d. Blower
i. Heat exchanger
e. Pump
7.2.1 Burner
Check the burner for debris. Remove the blower
arm assembly to access the burner. Remove the 4 bolts
connecting the blower to the arm (
see Figure 23
).
Remove the 5 bolts, which hold the burner arm in place.
Pull burner up and out. Clean burner, if necessary, by
blowing compressed air from the outside of the burner
into the center of the burner, and wipe the inside of the
burner clean with glass cleaner. A dirty burner may be
an indication of improper combustion or dirty
combustion air. Determine the cause, and correct. If
damaged, replace the burner gasket when replacing the
burner.
NOTE: When installing the burner, make sure the
flange is aligned with the mating surface, as each is
keyed to control fit.
7.2.2 Modulating Gas Valve / Venturi
The modulating gas valve consists of a valve body
that incorporates the ON/OFF gas flow control and a
negative pressure regulator. It provides the air/gas ratio
control in combination with the venturi to the unit. It is
designed to operate with gas supply pressure between 4
and 13 inches w.c.. To remove the gas valve and or
venturi. Shut off the 120 Volt power supply to the
boiler. Turn off all manual gas valves connecting the
boiler to the main gas supply line. Remove the front
door of the boiler to gain access to the gas valve and
venturi. Disconnect the four (4) flange bolts connecting
the gas manifold pipe to the gas valve. Remove the
electrical connections to the gas valve. Remove the bolts
connecting the venturi flange to the blower. This allows
the entire gas valve/venturi assembly to be removed as
an assembly to facilitate inspection and cleaning.
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 120 Volt power. Place the unit in
operation following the instructions in
Section 6.2
.
Once the boiler is operating check for leaks again and
confirm all fasteners are tight.
Check appliance setup according to
Section 6.2
.
7.2.3 Appliance Control
The NeoTherm appliance control is an integrated
control that incorporates the manual reset high limit
control, the 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 trouble shooting practices prior to replacing
the control. If control replacement is required, turn off
all power to the appliance. Shut all manual gas valves to
the appliance. Remove the front door to the appliance
and the control panel plastic bezel. 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 push in on the two tabs on the left
side of the board to unlatch the clips from the control
panel. Rotate the control around the fastening points on
the right side of the control to remove the hooks from
the control panel. To replace the control repeat the steps
above in the reverse order making sure to connect all
wires in the proper location. Place the appliance in
operation following the steps outlined in
Section 6.2
.
7.2.4 Ignitor Assembly
The ignitor assembly is a two rod system that
consists of a ground rod and a sense rod. To remove the
ignitor assembly, shut off the 120 Volt power supply to
the appliance. Turn off all manual gas valves connecting
the appliance to the main gas supply line. Remove the
front door of the boiler to gain access to the ignitor
assembly. Remove the two wires connected to the
assembly. Then remove the two bolts connecting the
ignitor assembly to the burner door. Remove and
replace the old ignitor assembly gasket. Reinstall a new
ignitor assembly in the reverse order if the old assembly
is determined defective. Replace gasket if necessary.
7.2.5 Flame Sensor
The flame sensor is a single rod system. To replace
the flame sensor electrode, shut off the 120 Volt power
supply to the boiler. Turn off all manual gas valves
connecting the boiler to the main gas supply line.
Remove the front door of the boiler to gain access to the
flame sensor electrode. Remove the flame sensor wire