4
This manual is intended to guide
engineers in the installation and
maintenance of Grant VORTEX Pro
External modules. A User guide for the
operation of this boiler is attached to
the reverse of this manual.
The following special text formats are
used in this manual for the purposes
listed below:
Warning of possible human injury as
a consequence of not following the
instructions in the warning.
Caution concerning likely damage
to equipment or tools as a
consequence of not following the
instructions in the caution.
Note text. Used for emphasis or
information not directly concerned
with the surrounding text but of
importance to the reader.
1.1 How a Condensing Boiler Works
During the combustion process,
hydrogen and oxygen combine to
produce heat and water vapour. The
water vapour produced is in the form
of superheated steam in the heat
exchanger. This superheated steam
contains sensible heat (available heat)
and latent heat (heat locked up in the
flue gas). A conventional boiler cannot
recover any of the latent heat and
this energy is lost to the atmosphere
through the flue.
The Grant VORTEX Pro condensing
boiler contains an extra heat
exchanger which is designed to
recover the latent heat normally lost by
a conventional boiler. It does this by
cooling the flue gases to below 90°C,
thus extracting more sensible heat
and some of the latent heat. This is
achieved by cooling the flue gases to
their dew point (approximately 55°C).
1Introduction
NOTE
!
CAUTION
!
WARNING
!
To ensure maximum efficiency, the boiler
return temperature should be 55°C or
less, this will enable the latent heat to be
condensed out of the flue gases.
• The boiler will achieve net thermal
efficiencies of 100%.
To achieve maximum performance
from the Grant Vortex Pro boiler, it is
recommended that the heating system
is designed so that a temperature
differential of 20°C between the flow
and return is maintained. The use of
modulating circulating pumps (now
widely available) and effective control
systems should be considered.
The Grant VORTEX Pro boiler will
however still operate at extremely
high efficiencies even when it is not
in condensing mode and therefore is
suitable for fitting to an existing heating
system without alteration to the radiator
sizes. The boiler is capable of a maximum
flow temperature of 75°C.
1.2 Boiler Description
Grant VORTEX Pro External modules
have an insulated weatherproof
enclosure made of galvanised steel with
a powder coated finish, and are designed
for external installation, either against a
wall or free standing some distance away
from the property, as required.
The External modules are part of the
Grant range of automatic pressure jet
oil boilers which have been designed for
use with a fully pumped central heating
system with indirect domestic hot water
cylinder. They are not suitable for use
with either a direct cylinder or a 'primatic'
cylinder or gravity hot water.
The boilers are suitable for use on
open vented or sealed central heating
systems.
All models are supplied with the
control panel and burner factory fitted.
The factory fitted low level discharge
flue system can be adjusted on site for
either rear, left hand or right hand flue
outlet position as required.
Introduction
An external conventional flue (Green)
system (Figure 9-3) is also available
from Grant UK. Refer to Section 9.2 for
further details.
A Hybrid flue (Green/Orange) system
(Figure 9-1) is also available which
allows the External module to utilise
an existing chimney stack. Refer to
Section 9.2 for further details.
Where an existing chimney is to be
lined - Grant recommends the use
of the Grant ‘Orange’ flue system,
specifically designed for the Vortex
range of condensing boilers. Refer to
Section 9.2 for further details.
Where a rigid conventional flue is
required, Grant recommends the use
of the Grant 'Green' and 'Orange'
flue system components. As no flue
adaptor is supplied with the boiler
it will be necessary to purchase the
correct Grant Starter Elbow in order
to connect this system to the boiler.
Refer to Section for further details.
The 'Green' and 'Orange' system
components can be used to construct
a flue of maximum vertical height 19
metres.
The flue system materials and
construction MUST be suitable
for use with oil-fired condensing
boilers. Failure to fit a suitable
conventional flue may invalidate the
warranty on the boiler.
A horizontal system - see Figure
9-4, is also available up to 3 metres -
components available:
• Straight starter
• Extensions 150 mm, 250 mm, 450 mm
and 950 mm
• Adjustable extension 195 to 270 mm
• 45° elbow
• Straight terminal
NOTE
!
