Introduction; How A Condensing Boiler Operates; Boiler Description; Flue Options - Grant Vortex Series Installation And Servicing Instructions

1

INTRODUCTION

1.1 HOW A CONDENSING BOILER
OPERATES
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 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).
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 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 Grant Vortex 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 Combi 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 Grant Vortex Pro Combi range of automatic pressure jet oil
boilers have been designed for use with a sealed central heating
system and will supply domestic hot water at mains pressure.
The boilers are suitable for use on sealed central heating
systems only. All combi models are supplied with the necessary
components factory fitted. Refer to Section 7.
All boilers are supplied with the control panel and burner factory
fitted.
All the models in the current Grant Vortex Pro Combi range of
boilers are designed to comply with the maximum NOx emissions
under the Energy-related Products Directive (ErP).
* From the 26th September 2018, the maximum NOx emissions
for all new oil fired boilers (up to and including 400kW for both
new build and replacement boiler installations) is 120mg/kWh.
Page 4
1.3

FLUE OPTIONS

Grant Vortex Pro External Combis are supplied with a low level
discharge flue system, which can either be fitted to the rear, left
hand or right hand flue outlet position, as required.
It is possible to discharge the products of combustion at a higher
level by using the following components from the Grant 'Green'
flue system:
• External module starter (available as a straight section or
with a 90° elbow, enabling the installer to use any flue outlet
from the boiler casing)
• Fixed extensions 150mm, 250mm, 450mm and 950mm
• Adjustable extension 195 to 270mm
• 45° elbow
• High level 90° or vertical terminal
It is possible to extend the flue system by 19m vertically (from the
boiler outlet) using this system.
Should the flue system need to navigate around objects, the
green system can be used to horizontally extend the flue system
by up to 3m from the centre of the boiler outlet.
Please note, the flue may either be brought up vertically from the
boiler, or horizontally. Not a combination of the two.
Alternatively, the plume diverter kit, available from Grant UK, can
be used to vertically extend the flue system.
Please see Sections 4.7 and 9 for more detailed instructions on
how to install the flue system.
Conventional flues only may be fitted to Grant Vortex Pro External
Combi boilers.
! NOTE !
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
guarantee on the boiler.
Section 1: Introduction