6
Installation & Operation Manual
Ratings
Crest
AHRI Rating
Model Number
Note: Change “N” to
“L” for L.P. gas models.
Input
MBH
(Notes 4 - 6)
Min Max
Gross
Output
MBH
(Note 1)
Net
AHRI
Ratings
Water,
MBH
(Note 2)
FB(N,L)1500
60
1500
1380
1200
FB(N,L)2000
80
2000
1840
1600
FB(N,L)2500
125
2500
2300
2000
FB(N,L)3000
150
3000
2760
2400
FB(N,L)3500
200*
3500
3220
2800
FB(N,L)4000
335
4000
3720
4043
FB(N,L)5000
500
5000
4650
3235
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.)
96
4"
4"
1 1/2"
7"
7"
2500
132
4"
4"
1 1/2"
8"
8"
3055
161
4"
4"
2"
8"
9"
3650
181
4"
4"
2"
10"
10"
4125
215
4"
4"
2"
10"
10"
4750
291
4"
4"
2 1/2"
12"
12"
6500
380
4"
4"
2 1/2"
14"
14"
8000
Maximum allowed working pressure is located on the rating plate.
NOTICE
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 2.2%
for each 1,000 feet above sea level up to 4,500 feet.
5. High altitude Crest Models 1.5, 2.0, 2.5, 3.0 and 3.5 are
equipped to operate from 3,000 to 12,000 feet
only
. Th
e
boiler will de-rate by 1.4% for each 1,000 feet above sea
level up to 5,500 feet and 1.8% 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.
Figure A High Altitude Label Location
*For LP models the minimum input is 420 MBH.
6. High altitude Crest Models 4.0 and 5.0 will not de-rate up to
5,500 feet.
7. For Crest Models 4.0 and 5.0, installations above 5,500 feet
contact the factory.
8. Ratings have been confi rmed by the Hydronics Section of
AHRI.
