0108RPVDGBEN
6
SECTION 3 INSTALLING
3.1
When the RPV 2000 is installed as an in line duct
heater i.e. not fitted within an air handling
appliance cabinet it is necessary to ensure that
clearance is maintained around the appliance from
combustible materials and for service access. The
clearances necessary to ensure safety for
combustibles is 150 mm on all sides. Service
access should be allowed on the controls side of
the appliance equal to the width of the air heater
plus 200 mm, this distance allows for the removal
of the burner tray assembly, necessary when
servicing the appliance.
3.2
Ensure that the structural elements which will be
used to suspend or support the appliance, are
adequate to carry the weight of the appliance and
its ancillary components i.e. flue system and any
connected duct-work.
3.3
Ensure that the air heater is installed in a level
plain.
3.4
If the air heater is to be base mounted in an open
position then it must be secured to supporting
devices.
3.5
After installation, the air heater should be rigid so
as to avoid placing a strain on the gas services,
electrical wiring, duct-work, etc.
3.6
RPV 2000 Series air heaters, wether or not they
are installed within an air handling appliance may
be installed in multiple form as illustrated in figure
4. In all instances the air flow passed through the
appliance/s should not exceed the volumes
required to ensure that dew point conditions within
the combustion circuits/s as indicated in figure 3
do not occur.
By-passes should be constructed as necessary to
ensure that the optimum temperature rises are met
taking into account the pressure resistance of the
air heater as indicated in figure 2.
When designing by-pass ducts ensure that the
requirements for service access, flue and controls
connections are maintained. An adjustable damper
should be included within by-pass ducts to enable
air flow pressure and volume to be adjusted after
installation.
When fitting RPV 2000 air heaters in a side by side
configuration it is necessary to specify this
requirement when ordering. Whilst the air may be
passed through the appliance from either end,
provision for locating the thermal over-heat (limit)
control device has to be made so that the air off
side (the hottest side) is monitored for this
purpose.
3.7
Figure 5. illustrates the recommended principle
that should be used for the connection of ducting
or air handling appliance element transitions.
A positive seal must be maintained between the air
circuit and the air heater, this is particularly
important when the air heater is installed within an
air handling cabinet. A neutral pressure zone
around the appliance must be maintained to ensure
that the atmospheric burner operates at all times at
normal ambient pressure.
3.8
Figure 6 illustrates some of the situations to be
avoided when connecting an air handler to the
appliance. A rule of connecting a straight length of
ducting equal to 3 times an equivalent duct
diameter onto the appliance should be maintained
whenever possible. It is essential that an even air
flow is distributed across the heat exchanger to
ensure that the heat is scrubbed from all the
exchanger elements thus preventing hot spots
which will greatly reduce the working life of the air
heater.
Always avoid installing a centrifugal fan so that the
swirl effect created by the direction of rotation is
counter directive. As well as the effect of uneven
air flows, excessive loss of static pressure is
created resulting in inefficiency of the fan.
Where it is necessary to connect a transition
section as part of the connection then the degree
of taper in any plain should not be greater than
15
°
. Abrupt transitions create excessive pressure
drops and lead to uneven air distribution across the
air heater.
