UHA S
TANDARD
U
NIT
H
EATER
I
NSTALLATION
O
PERATION
AND
S
ERVICE
M
ANUAL
12 of 51
7.2.1 Standard Vented Heaters
(Models UHA[X] 150 - 400)
The vent m
u
st be fitted
w
ith a lo
w
resistance
terminal.
See Page 13, Figure 6
through Page 14,
Figure 7
. Standard vented heaters do not allo
w
o
u
tdoor air intake for comb
u
stion air.
7.2.2 Separated Combustion Heaters
(Models UHA[X]S 150 - 400)
The heaters are designed to be installed as
separated comb
u
stion heaters. The vent and air
intake are r
u
n as separate pipes to the
w
all or roof
terminals.
See Page 16, Figure 9
. As an option, the
vent and air intake are r
u
n as separate pipes to a
concentric vent box and a concentric vent/air intake
pipe penetrates the
w
all or roof.
See Page 16,
Figure 10
and Page 17, Figure 11
.
For separated comb
u
stion installation, the vent and
air intake m
u
st be fitted
w
ith an individ
u
al and
correctly sized sealed system and the vent and air
intake m
u
st terminate at approved
w
all and roof
terminals.
Separated comb
u
stion
u
nits may not be common
vented.
See Page 11, Section 7
.
7.3 Unvented Operation
This heater is not approved to be installed in
residential b
u
ildings.
For
u
nvented operation in commercial installations,
s
u
fficient ventilation m
u
st be provided in the amo
u
nt
of 4 cfm per 1000 Bt
u
/h firing rate (United States); 3
cfm per 1000 Bt
u
/h firing rate (Canada).
7.4 Horizontal Ventin
g
Horizontally vented heaters m
u
st be individ
u
ally
vented.
Vent pipe m
u
st be sloped ¼" (.6 cm) for every 1' (.3
m). For vent lengths greater than 5' (1.5 m),
condensation
w
ill form. Ins
u
lation is recommended
and condensation drains may be desired. For vents
pitched
u
p to
w
ard the vent terminal, place the
condensation drain
w
ithin 5' (1.5 m) of the heater.
In noncomb
u
stible
w
alls only, vent terminal
(P/N 02537801-1P) may be
u
sed.
For 4'' (10 cm) vents in either comb
u
stible or
noncomb
u
stible
w
alls,
u
se vent terminal (P/N
90502100) or eq
u
ivalent ins
u
lated vent terminal.
Follo
w
the man
u
fact
u
rer's instr
u
ctions for proper
installation.
Instead of an ins
u
lated vent terminal, a listed thimble
w
ith 2" (5 cm) air gap, may be
u
sed
w
ith a 4" (10 cm)
vent cap (P/N 90502102).
7.5 Vertical Ventin
g
Vertically-vented standard-vented heaters can be
common vented (
u
p to 4 heaters).
For vent lengths greater than 5' (1.5 m),
condensation
w
ill form. Ins
u
lation is recommended
and condensation drains may be desired. Vent from
the rear of the heater cabinet then r
u
n the vent
vertically and
u
se a condensate drain at the bottom
of the vertical vent.
Vent pipe m
u
st be sloped 1/4'' (.6 cm) for every
1' (.3 m).
For 4'' (10 cm), an approved vent cap
(P/N 90502102) m
u
st be
u
sed.
For 6'' (15 cm) common vent, an approved vent cap
(P/N 90502103) m
u
st be
u
sed.
For common vertical venting of more than t
w
o
heaters,
See Page 15, Figure 8
.
A vent shall not extend less than 2' (.6m) above the
highest point
w
here it passes thro
u
gh a flat roof of a
b
u
ilding.
7.6 Len
g
th Re
q
uirements
If
u
sing vent lengths greater than 5' (1.5 m),
condensation
w
ill form in the vent pipe. Ins
u
lation
and additional sealing meas
u
res (high temperat
u
re
silicone at all seams) are req
u
ired.
The entire vent sho
u
ld be ins
u
lated
w
ith foil faced
fiberglass ins
u
lation (1/2" thick, 1-1/2# density
minim
u
m).
WARNING
Carbon Monoxide Hazard
Heaters may be installed
vented or unvented.
Vented heaters must be
vented outdoors.
Unvented heaters must be
installed according to the
installation manual.
Failure to follow these
instructions can result in
death or injury.