Install Instructions

11
I-UBX-UBZ-UDX-UDZ (04-21) 1034344-0
Table 7. Unit Weights
Model
Unit Size
030 045 060 075 100 125 150 175 200 225 250 300 350 400
Pounds (kg)
UBX
84
(38)
89
(40)
102
(46)
108
(49)
168
(76)
171
(78)
300
(136)
320
(145)
320
(145)
385
(175)
400
(181)
458
(208)
494
(224)
506
(230)
UBZ
85
(39)
90
(41)
103
(47)
109
(49)
169
(77)
172
(78)
301
(137)
321
(146)
321
(146)
386
(175)
401
(182)
459
(208)
495
(225)
507
(230)
UDX
57
(26)
62
(28)
71
(32)
76
(34)
101
(46)
106
(48)
178
(81)
193
(88)
193
(88)
211
(96)
223
(101)
277
(126)
303
(137)
316
(143)
UDZ
58
(26)
63
(29)
71
(32)
77
(35)
102
(46)
107
(49)
179
(81)
194
(88)
194
(88)
212
(96)
224
(102)
278
(126)
304
(138)
317
(144)
Combustion Air Requirements
⚠ WARNING ⚠
• Do not install a unit in a confined space without providing wall openings leading to and from
the space.
• Unit heater models UBX and UDX are designed to take combustion air from the space in which
the unit is installed and are not designed for connection to outside combustion air intake ducts.
Connecting outside air ducts voids the warranty and could cause hazardous operation.
• For UBZ and UDZ models, refer to the combustion air requirements in the venting instructions listed in Table 1.
• UBX and UDX models must be supplied with the air that enters into the combustion process and is then vented
to the outdoors. Sufficient air must enter the equipment location to replace that which is exhausted through the
heater vent system.
• In the past, the infiltration of outside air assumed in heat loss calculations (one air change per hour) was assumed
to be sufficient. However, current construction methods, which use more insulation, vapor barriers, tighter fitting and
gasketed doors and windows, weather-stripping, and/or mechanical exhaust fans, may now require the introduction
of outside air through wall openings or ducts.
• Under all conditions, enough air must be provided to ensure there will not be a negative pressure condition within
the equipment room or space.
• Requirements for combustion air and ventilation air depend upon whether the unit is located in a confined or
unconfined space. A confined space is defined as a space whose volume is <50 cubic feet per 1,000 BTUh of the
installed appliance input rating. An unconfined space is defined as a space whose volume is ≥50 cubic feet per
1,000 BTUh of the installed appliance input rating.
• For confined space installation of UBX and UDX models (including those with CV option), provide openings
(depending on the combustion air source) near the floor and ceiling for ventilation and air for combustion, as shown
in Figure 4 and as listed in Table 8.
NOTE: For further details on supplying combustion air to a confined space, refer to the National
Fuel Gas Code ANSI Z223.1a (latest edition).
Figure 4. Confined Space Combustion Air Openings (Refer to Table 8)
CONFINED
SPACE
A
AB
B
C
C