page no. 28 of 36
NVS Range Users, Installation & Servicing Instructions Doc Ref M102 issue 2.4 May 2018.
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.
2.7.5 Main Fan Assembly
2.7.5.1. NVS/F 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. Condense Drain & Trap
Ensure that the condense trap is clean and that the
drainage pipe work is not blocked or damaged.
2.7.7. Replacement of Faulty Components
2.7.7.1 Multifunctional Control
1. If there is movement available on the incoming gas pipe
work e.g. a flexible connection has been used go to step
2 otherwise remove the burner assembly as previously
described in Section 2.7.2.
2. Remove the electrical plug connections from the top of
the multifunctional control.
3. Release the flanged connections at the inlet and
outlet of the multifunctional control and remove the
multifunctional control.
4. Reconnect the new valve in the reverse order to that
above ensuring that the valve is correctly orientated.
Renew the sealing 'O' rings if necessary.
2.7.7.2. Burners
1. Remove the burner assembly as described in Section
2.7.2.
2. Remove the end plates of the burner assembly and the
central burner support plate.
3. Exchange burners as required and reassemble
components in reverse order.
4. Re-commission the appliance as described in Section 2.6.
2.7.6.3. Electrode Assemblies
1. Disconnect the electrode leads from the control box as
appropriate.
2. Remove the screw securing the electrode assembly to
the burner assembly side plate and withdraw the assembly.
3. Fit replacement and reassemble in reverse order. Check
that the spark gap is 2.5mm (See section 2.6.3) and the
rectification electrode is 10 - 12mm forward of the burner.
