Combat HVAC ELU 100, Installation And Commissioning Manual, Page: 20 / 52

Unit Heater Installation, Commissioning, Operation and Service Manual
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Combat Elite Unit Heater EL231117 Orig
Air Supply
SECTION 8
8.1 Room Sealed Installation
When installed as a room sealed heater, the air for combustion is drawn
in from outside the building. It is important to ensure that there is
adequate ventilation to provide air for the distribution fan(s).
8.2 Open Flued Installation
It is important to ensure that there is adequate air supply at all times for
both combustion and heating requirements in accordance with local
and national regulations.
8.2.1 Heaters Installed Within the Heated Space
Where the volume of the heated space is greater than 4.7m3 per
kilowatt of total rated heat input and the air change rate is at least 0.5/h,
additional high and low-level ventilation will not be required.
For a building having an air change rate less than 0.5/h, ventilation
will be will be necessary in accordance with local and national codes.
Ventilation direct to outside must be provided as follows:
Heaters up to 70kW heat input: 5.0cm² per kW of rated heat input.
Heaters above 70kW heat input: 350cm² + 2.5cm² per kW of rated heat
input above 70kW.
8.3 Building Ventilation
Where ventilation is required, air must be taken from an outside point
where it is not likely to be contaminated or obstructed.
Where natural ventilation is used, suitable ventilation with outside air
at low level must be provided in accordance with Section 8.2.1 and local
and national regulations.
Where mechanical ventilation is used extract rate must be 5% - 10%
less than the inlet rate. The mechanical ventilation must be interlocked
with the burner on the heater.
8.4 Isolated Equipment Rooms
Ventilation must prevent the isolated equipment room temperature from
exceeding 32oC as well as prevent any negative air pressure within the
room. See Page 15, Figure 9. Any isolated equipment room containing
air heaters will require permanent air vents direct to outside air in
compliance with local regulations.
Where natural ventilation is used, suitable permanent openings at low
and high level, communicating directly with the outside air, must be
provided.
Where mechanical ventilation is used, extract rate must be 5% - 10%
less than the inlet rate. The mechanical ventilation must be interlocked
with the burner on the heater.
Figure 9: Heaters Installed In Isolated Equipment Rooms