Reznor UDBS Unit Installation Manual - Manual (Page 16)

Form I-UDB, P/N 202658 R14, Page 16
Combustion Air
Requirements for a
Heater Located in
a Confined Space -
applies to Model UDBP
6.2 Combustion Air - Models UDBP
This heater 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 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 suf-
ficient. However, current construction methods using 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.
The requirements for combustion and ventilation air depend upon whether the unit is
located in a confined or unconfined space. An “unconfined space” is defined as a space
whose volume is not less than 50 cubic feet per 1000 BTUH of the installed appliance.
Under ALL conditions, enough air must be provided to ensure there will not be a
negative pressure condition within the equipment room or space.
WARNING
Model UDBP power-vented unit heaters 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. See Hazard Levels, page 2.
Do not install a unit in a confined space without providing wall openings leading to and
from the space. Provide openings near the floor and ceiling for ventilation and air for
combustion as shown in FIGURE 11, depending on the combustion air source as noted
in Items 1, 2, and 3 below.
Add total BTUH of all appliances in the confined space and divide by figures below for
square inch free area size of each (top and bottom) opening.
(Note: For Model
UDBS, see
Venting Manual
for combustion air
requirements.)
6.0 Mechanical
(cont’d)
6.1 Gas Piping and Pressures (cont’d)
6.1.3 Derate by Valve Outlet Pressure Adjustment for High Altitude
Operation (cont’d)
High Altitude
Capacity Changes
(cont’d)
BTUH Inputs and Capacities by Altitude in the UNITED STATES for Model UDBP and Model UDBS (cont'd)
ALTITUDE
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Feet Meters Size 200 Size 225 Size 250 Size 300
0-2000 0-610 200000 166000 140000 225000 186750 157500 250000 207500 175000 300000 249000 210000
2001-3000 611-915 188000 156040 131600 211500 175545 148050 235000 195050 164500 282000 234060 197400
3001-4000 916-1220 184000 152720 128800 207000 171810 144900 230000 190900 161000 276000 229080 193200
4001-5000 1221-1525 180000 149400 126000 202500 168075 141750 225000 186750 157500 270000 224100 189000
5001-6000 1526-1830 176000 146080 123200 198000 164340 138600 220000 182600 154000 264000 219120 184800
6001-7000 1831-2135 172000 142760 120400 193500 160605 135450 215000 178450 150500 258000 214140 180600
7001-8000 2136-2440 168000 139440 117600 189000 156870 132300 210000 174300 147000 252000 209160 176400
8001-9000 2441-2745 164000 136120 114800 184500 153135 129150 205000 170150 143500 246000 204180 172200
9001-10000 2746-3045 160000 132800 112000 180000 149400 126000 200000 166000 140000 240000 199200 168000
Feet Meters Size 350 Size 400
0-2000 0-610 350000 290500 245000 400000 332000 280000
2001-3000 611-915 329000 273070 230300 376000 312080 263200
3001-4000 916-1220 322000 267260 225400 368000 305440 257600
4001-5000 1221-1525 315000 261450 220500 360000 298800 252000
5001-6000 1526-1830 308000 255640 215600 352000 292160 246400
6001-7000 1831-2135 301000 249830 210700 344000 285520 240800
7001-8000 2136-2440 294000 244020 205800 336000 278880 235200
8001-9000 2441-2745 287000 238210 200900 328000 272240 229600
9001-10000 2746-3045 280000 232400 196000 320000 265600 224000
BTUH Inputs and Capacities by Altitude in CANADA for Models UDBP and UDBS
ALTITUDE
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Normal
Input
Thermal Output
Capacity
Minimum
Input
Feet Meters Size 30 Size 45 Size 60 Size 75
0-2000 0-610 30000 24600 30000 45000 37350 45000 60000 49800 42000 75000 62250 52500
2001-4500 611-1373 27000 22140 27000 40500 33615 40500 54000 44820 37800 67500 56025 47250
Feet Meters Size 100 Size 125 Size 150 Size 175
0-2000 0-610 105000 88200 73500 120000 100800 84000 150000 124500 105000 175000 145250 122500
2001-4500 611-1373 94500 79380 66150 108000 90720 75600 135000 113400 94500 157500 132300 110250
Feet Meters Size 200 Size 225 Size 250 Size 300
0-2000 0-610 200000 166000 140000 225000 186750 157500 250000 207500 175000 300000 249000 210000
2001-4500 611-1373 180000 151200 126000 202500 170100 141750 225000 189000 157500 270000 226800 189000
Feet Meters Size 350 Size 400
0-2000 0-610 350000 290500 245000 400000 332000 280000
2001-4500 611-1373 315000 264600 220500 360000 302400 252000