Addison UHAS 150, Installation, Operation & Service Manual

Page: 26 / 74

UHA S
TANDARD
U
NIT
H
EATER
I
NSTALLATION
O
PERATION AND
S
ERVICE
M
ANUAL
18 of 59
SECTION 8: AIR SUPPLY
WARNING
Explosion Hazard
Equipment must have access to
uncontaminated air at all times.
Failure to follow these instructions can result
in death, injury or property damage.
8.1 Separated Combustion Installation
When installed as a separated combustion heater
(UHA[T][X]S), the air for combustion is drawn in
from outside the building. It is important to ensure
that there is adequate space around heater to
provide air for the axial air distribution fan.
8.2 Unvented Installation
It is important to ensure that there is adequate fresh
air supply at all times for both combustion and
heating requirements in accordance with local and
national codes.
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.
8.4 Outside Combustion Air Supply
If outside combustion air supply is required,
separated combustion model (UHA[T][X]S) heaters
must be used.
Caution: If the building has a slight negative
pressure or corrosive contaminants such as
halogenated hydrocarbons are present in the air, an
outside combustion air supply to the heater is
required. Seal all combustion air pipe joints. For
models 300-400, the flexible air duct may be
insulated to prevent condensation on the outer
surface. The outside air terminal must not be more
than 1' (31 cm) above the vent terminal.
8.4.1 Length Requirements
Follow the constraints listed on Page 12, Section 7.6 .