Dual Fuel Supplemental Manual
Ratings
Crest
AHRI Rating
Model Number
Note: Change “N” to
“L” for L.P. gas models.
Input
MBH
(Notes 4 - 8)
Min Max
Gross
Output
MBH
(Note 1)
Net
AHRI
Ratings
Water,
MBH
(Note 2)
FB(N,L,D)0751
50
750
720
626
FB(N,L,D)1001
50
1000
960
835
FB(N,L,D)1251
62
1250
1200
1043
FB(N,L,D)1501
60
1500
1440
1252
FB(N,L,D)1751
70
1750
1680
1460
FB(N,L,D)2001
80
2000
1920
1670
Maximum allowed working pressure is located on the rating plate.
NOTICE
Figure A High Altitude Label Location
5
Other Specifications
Appliance
Water
Content
Gallons
Pipe
Size
Outlet
Pipe
Size
Inlet
Gas Inlet
Size
Air
Size
Vent
Size
(Note 3)
Weight
w/Water
(lbs.)
73
3"
3"
1 1/4"
6"
6"
1768
77
3"
3"
1 1/4"
6"
6"
1838
87
3"
3"
1 1/4"
6"
8"
1975
94
4"
4"
1 1/2"
8"
8"
2307
106
4"
4"
1 1/2"
8"
8"
2458
111
4"
4"
1 1/2"
8"
8"
2570
Notes:
1. The ratings are based on standard test procedures
prescribed by the United States Department of Energy.
2. Net AHRI ratings are based on net installed radiation of
sufficient quantity for the requirements of the building
and nothing need be added for normal piping and
pickup. Ratings are based on a piping and pickup
allowance of 1.15.
3. Crest boilers require special gas venting. Use only
the vent materials and methods specified in the Crest
Installation and Operation Manual.
4. Standard Crest boilers are equipped to operate from sea
level to 4,500 feet
only
. The boiler will de-rate by 1.4%
for each 1,000 feet above sea level up to 4,500 feet.
5. High altitude Crest Models are equipped to operate from
3,000 to 12,000 feet
only
. Th
e boiler will not de-rate up
to 5,500 feet and will de-rate by 1.6% for each 1,000 feet
above 5,500 feet. Th
e operation given in this manual
remains the same as the standard boilers. A high altitude
label (as shown in FIG A.) is also affi
xed to the unit.
De-rate values are based on proper combustion
calibration and CO
2
’s adjusted to the recommended
levels.
UNIT EQUIPPED FOR
HIGH ALTITUDE
3,000 FT. TO 12,000 FT.
IMG01026
