page no. 37 of 44
NVx Range Users, Installation & Servicing Instructions issue 6.4 Aug 2017.
2.7.5 Main Fan Assembly
2.7.5.1. NVx/F & /CCF Models
1. Inspect the fan blades for any damage or excessive
buildup of deposits that could give rise to an imbalance.
Remove the assembly for cleaning as follows.
2. Slacken the cable gland on the heater casing through
which the fan electrical cable passes.
3. Disconnect the fan leads from the electrical terminals.
4. Withdraw cable through entry grommet.
5. Remove the fan and motor assembly complete by
removing the hexagon headed screws that secure the fan
to the rear panel.
6. Reassemble in reverse order.
2.7.5.2. Centrifugal Fan/Silencer Section
1. Remove section side panel(s) and inspect the fan blades
for any damage or excessive buildup of deposits that
could give rise to an imbalance. Remove the assembly for
cleaning as follows.
2. Slacken the cable gland on the casing through which the
fan electrical cable passes.
3. Disconnect the fan leads from the electrical terminals in
the contactor enclosure.
4. Withdraw cable through entry grommet.
5. Remove the complete fan assembly by removing the
fixings securing the fan to the base rails.
6. Reassemble in reverse order.
2.7.6. Replacement of Faulty Components
2.7.6.1 Multifunctional Control
1. Ensure that the gas service valve is turned OFF. If a
flexible gas connection has been used go to step 2
otherwise unscrew the union nut situated immediately
downstream of the gas service valve.
3. Remove the burner heat shield, 3 screws.
4. Release the inlet connection flange from the gas valve by
removing the four screws.
5. If required remove the manifold by removing the four
screws securing it to the burner assembly.
6. Remove the two screws that secure the top of the burner
assembly to the bulkhead and lift out burner assembly.
7. Using a stiff brush, not a wire brush, brush the burners
to dislodge accumulated deposits. Inspect the burners
both internally and externally to ensure that they are clean.
Examine the injectors and if damaged or deteriorated,
replace with new ones of the correct size and marking. If
deemed necessary, clean the injectors. Do not broach out
with wire.
8. Reassemble the injectors, manifold and burners in
reverse order to that above.
2.7.3. Ignition and Rectification Electrodes
Note: The ignition electrode is located at the
bottom of the burner assembly, the rectification
electrode is located at the top of the burner
assembly.
Inspect the electrodes, making sure that they are in a
sound and clean condition. In particular check that the
ignition electrode is clean and undamaged. Check that the
spark gap is 2.5mm and that the rectification probe is 10 -
12mm forward of the burner.
2.5mm
Ignition Electrode Spark Gap
2.7.4. Heat Exchanger
Whilst the main burner assembly is removed from the unit,
check that the primary sections that the burners fire into
are clean.
