UHA S
TANDARD
U
NIT
H
EATER
I
NSTALLATION
O
PERATION
AND
S
ERVICE
M
ANUAL
18 of 51
SECTION
8
: AIR SUPPLY
8
.1 Separated Combustion Installation
When installed as a separated comb
u
stion heater
(UHA[X]S), the air for comb
u
stion is dra
w
n in from
o
u
tside the b
u
ilding. It is important to ens
u
re that
there is adeq
u
ate space aro
u
nd heater to provide air
for the axial air distrib
u
tion fan.
8
.2 Unvented Installation
It is important to ens
u
re that there is adeq
u
ate fresh
air s
u
pply at all times for both comb
u
stion and
heating req
u
irements in accordance
w
ith local and
national codes.
8
.3 Buildin
g
Ventilation
Where ventilation is req
u
ired, air m
u
st be taken from
an o
u
tside point
w
here it is not likely to be
contaminated or obstr
u
cted.
8
.4 Outside Combustion Air Supply
If o
u
tside comb
u
stion air s
u
pply is req
u
ired,
separated comb
u
stion model (UHA[X]S) heaters
m
u
st be
u
sed.
Caution:
If the b
u
ilding has a slight negative
press
u
re or corrosive contaminants s
u
ch as
halogenated hydrocarbons are present in the air, an
o
u
tside comb
u
stion air s
u
pply to the heater is
req
u
ired. Seal all comb
u
stion air pipe joints.
The flexible air d
u
ct may have to be ins
u
lated to
prevent condensation on the o
u
ter s
u
rface. The
o
u
tside air terminal m
u
st not be more than 1' (31
cm) above the vent terminal.
8
.4.1 Len
g
th Re
q
uirements
Follo
w
the constraints listed
on Page 12, Section 7.6
.
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.
