Addison UHA 150, Installation, Operation & Service Manual

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UHA S
TANDARD
U
NIT
H
EATER
I
NSTALLATION
O
PERATION AND
S
ERVICE
M
ANUAL
6 of 49
SECTION 3: CRITICAL CONSIDERATIONS
3.1 Basic Information
UHA[X][S] heaters have a u tomatic ignition bu rners
for ON/OFF operation only.
3.2 Manufactured Units
Gas-fired, po w er-vented u nit heater w ith t ubu lar heat
exchanger. Units shall have a minim u m of 82%
thermal efficiency. The standard u nit shall consist of
a non-separated com bu stion design w ith an
al u minized heat exchanger. Design and heat
exchanger alternatives shall b e offered as follo w s:
• Separated Com bu stion: A separated com bu stion
u nit shall feat u re an enclosed, sealed bu rner
b ox. A piece of flexi b le air d u ct connects this
bu rner b ox to a flange on the ca b inet.
Com bu stion air sho u ld b e d u cted from o u tside
the heated space, w ith the d u ct w ork connecting
to the u nit w ith the u se of the flange.
• Stainless Steel Heat Exchanger: A stainless
steel heat exchanger u nit shall consist of heat
exchanger t ub es, heat exchanger t ub e s u pports,
heat exchanger t ub e plates and vent b ox
prod u ced of 409 stainless steel.
The u se of stainless steel heat exchanger u nit is
recommended w hen air inlet temperat u res are
b elo w 40° F (4.4°C) or temperat u re rise is less
than 40° F (22.2° C) as condensation may form
on the heat exchanger res
u lting in corriosion that
may shorten its life.
3.3 Location and Suspension
All models:
• M u st b e installed indoors.
• M u st b e installed in a level position w ith
horizontal discharge.
• May b e mo u nted on a shelf of non-com bu sti b le
material.
• May b e s u spended from a b ove ( See Page 10,
Figure 5 ) or from w all b rackets of s u fficient
strength to s u pport the heater as listed in the
Technical Data Ta b le on Page 48, Section 16.2 .
Drop rods m u st b e a minim u m of 3/8" diameter
mild steel. Fo u r s u spension points (3/8" n u ts)
are located on top of the heater.
• M u st b e installed in a manner w hich allo w s
access to all servicea b le components.
See Page 7, Figure 4 for details.
3.4 Minimum Re q uired Installation Clearances
Clearances aro u nd the heater and vent m u st b e as
indicated on Page 7, Figure 4 and Page 13, Figure 6
to ens u re access for servicing and correct operation.
3.5 Ventilation
It is important to ens u re that there is adeq u ate air
space aro u nd the heater to s u pply air for
com bu stion, ventilation and distri bu tion in
accordance w ith local and national codes on Page
11, Section 7 .
3.6 Gas Supply
It is important that the gas s u pply pipe is sized
correctly to provide the inlet press u re as stated on
the heater data plate. The gas s u pply pipe and
electrical connections m u st not s u pport any of the
heater's w eight on Page 19, Section 9 .
3.7 Electrical Supply
A permanent 120 V / 60 Hz / 1 Ø electrical s u pply is
req u ired for the main electrical po w er. The heater
also req u ires s u ita b le controls in accordance w ith
See Page 21, Section 10 .
3. 8 Vent
Choose heater orientation to allo w for the proper
location of the vent. Each heater m u st b e fitted w ith
a correctly sized sealed vent system.
If vented horizontally, no other appliance may b e
connected to the vent. See Page 11, Section 7 .