page no. 16 of 36
NVS Range Users, Installation & Servicing Instructions Doc Ref M102 issue 2.4 May 2018.
The minimum distance between surfaces of the flue pipe
and any surfaces made from combustible materials is
300mm.
If it is necessary for the flue pipe to pass through a
structure made from combustible materials a metal sleeve
must be used so that the minimum clearance of 300mm is
maintained.
The flue and combustion air ducts supplied with the heater
are capable of withstanding their own weight over the
allowable flue lengths. Wall bands and bracing brackets,
or equivalent, must be used to provide lateral stability and
should be used at centres not exceeding 2.5 metres.
All models are supplied as standard with a rear flue outlet
and the flue outlet and combustion air sockets temporarily
fitted.
2.2.1. Fitting Flue/Combustion Air Sockets
1. Apply a bead of silicon sealant around the face of the
flange on the exhaust fan outlet tube that can be seen
from the outside of the heater. Place the flue socket on the
outside of the heater to mate with this flange and clamp
the two flanges together, on either side of the heater panel
using the screws provided. Ensure that the silicon sealant
has sealed between the two flanges.
2. If ducted combustion air is not required (see Section
1.3.7.) fit the mesh inlet plate behind the unused
combustion air inlet hole.
3. Apply silicon sealant and refit blanking plates as required
to seal unused panel holes.
2.2.2. General Requirements
See Figures 1a to 2b for the different types of flue
installation. In all cases the flue outlet socket must be
connected via the provided flue system to outside air.
The maximum permitted length of flue system is 6m, or
12m if the flue outlet only is used. If an offset is required
two sets of 45° bends should be used each set being
equivalent to 0.5m of flue length. 90° bends may be used
but each set will be equivalent to 1.0m of flue length.
All outer joints must be finished with the provided locking
bands. A smear of silicon grease to the inside of sockets
will assist in fitting components together. All flue and
combustion air ducts must be supported independently
of the air heater. The flue or flue/combustion air terminal
must not be installed so as to be less than:
- 300mm below an opening e.g. window, air brick
etc.
- 200mm below eaves or gutter.
- 300mm from an internal or external corner.
- 1200mm from a surface facing the terminal.
- 1500mm vertically from another terminal on the same
wall.
- 300mm horizontally from another terminal on the same
wall.
- 2000mm from ground level.
2.2.3. Installation of Flue System
Note: A terminal guard, as supplied by
Powrmatic Ltd, must be fitted to horizontal flue
terminals.
Notes for all systems.
i) Final overall length of adjustable disconnection
piece must be between 360 - 415mm.
ii) 45° offsets may be used if required. Each set is
equivalent to 0.5m of flue length.
iii) Where NVS heaters are used in clean environments it
is permissible to take the combustion air directly from the
heated space. The supplied mesh intake plate, must be
fitted to the combustion air inlet on the rear of the heater.
2.2.3.1. Horizontal System - Rear Outlet
Note: If the outlet is required to the side of the
unit 90° bends may be fitted directly onto the
inlet/outlet spigots on the heater.
1. Locate the position of the flue terminal,
allowing for a slight gradient running down from the
heater to the terminal of 2° - 3° and cut a hole to suit.
2. Fit the flue terminal, securing via the wall plate and
weather with silicon sealant or similar.
3. Fit the twin to concentric adaptor to the terminal section
and extend the flue and combustion air ducts to the heater
using straight lengths. Fit an adjustable length prior to the
unit, to facilitate flue disconnection for servicing. Extend
the adjustable lengths to make the final connection to the
appropriate heater inlet/outlet spigots.
4. Ensure that internal silicon sealing rings are in place and
that all tubes are pushed fully home. Secure concentric
lengths with the locking bands provided.
5. A suitable 90° elbow should be fitted to the flue
condense drain pipe which in turn is connected to the
condense trap. See 2.2.4
2.2 Flue/Combustion Air Duct System
