6
110328-04 - 2/23
ALTA
Installation, Operating & Service Instructions
3
Specifications
(continued)
Table 3-3: Air Intake and Vent Lengths
Model Number Intake/Vent Size in. (mm)
Min Length ft.
(m)
Max Length ft.
(m)
Approx. Derate at Max. Length
(%)
ALTA-080
Standard
2 (60)
2.5 (0.76)
70 (21.3)
6
w/ increaser
3 (80)
2.5 (0.76)
135 (41.1)
1
ALTA-120
ALTA-120B
Standard
2 (60)
2.5 (0.76)
70 (21.3)
7
w/ increaser
3 (80)
2.5 (0.76)
135 (41.1)
1
ALTA-150
ALTA-180
Standard
2 (60)
2.5 (0.76)
70 (21.3)*
9
w/ increaser
3 (80)
2.5 (0.76)
135 (41.1)
5
*Reduced to 50 eq. ft. (15.2 m) for 150 and 180 boiler LP installation above 8,000 ft. (2,438 m)
Table 3-5: Inlet Gas Pressure Range
Min in. wc (kPa)
Max in. wc (kPa)
Natural Gas
2.5 (0.62)
14.0 (3.48)
LP Gas
8.0 (1.99)
Table 3-4: Altitude De-rates (%/1,000 ft.)
Boiler Model
2,000 to 6,000 ft.
(611 m to 1,828 m)
6,001 to 8,000 ft.
(1,829 m to 2,438 m)
8,001 to 10,100 ft.
(2,439 m to 3,079 m)
NG
LP
NG
LP
NG
LP
ALTA-080
0%
0%
0%
0%
0%
0.3%
ALTA-120
1.2%
3.5%
0.9%
2.5%
0.7%
1.9%
ALTA-120B
0%
2.6%
0%
1.8%
0%
1.4%
ALTA-150
0%
0%
0%
0%
0%
0%
ALTA-180
0%
0%
0%
0%
0%
0%
NOTE
: These de-rates are for minimum vent. When calculating de-rate from altitude and vent length, altitude de-rate
is applied first.