BOILER RATINGS AND CAPACITIES
PROCEDURE 1—EXPLANATION OF MODEL NUMBERS AND RATING PLATE
Boilers with the same number of sections are identical to each other except for their firing rate. The firing rate is determined by nozzle size in oil
burner and oil pressure at nozzle.
Each model number has 3 possible firing rates depending on which nozzle is installed. The model number represents the largest possible output
for the unit. For example, a BW4AAH120AAAA has a maximum output of 120,000 Btuh. The rating plate for each model shows the three possible
firing rates. Boilers come shipped with the largest nozzle installed. By changing nozzles, the BW4AAH120AAAA firing rate can be changed to
92,000 or 74,000 Btuh output.
PROCEDURE 2—GENERAL INFORMATION
Selection of boiler size should be based upon "Net I=B=R Rating MBH" being equal to or greater than calculated heat loss of building.
The Net I=B=R Ratings shown are based on an allowance of 1.15 in accordance with factors in the I=B=R Standard as published by The Hydronics
Institute.
These boilers are low-pressure, sectional cast iron boilers constructed and hydrostatically tested for a maximum working pressure of 50 psi in
accordance with the American Society of Mechanical Engineers (A.S.M.E.) Section IV Standards for cast iron heating boilers. They are capacity
rated in accordance with the code of the Hydronics Institute.
Fig. 1—Dimensional Drawing and Boiler Ratings and Capacities
Oil-Fired Hot Water Boiler Ratings
BOILER MODEL NUMBER
NO. OF
SECTIONS
INPUT
MBH
HEATING
CAPACITY
MBH*
NET
I=B=R
RATING
MBH
MAXIMUM
FIRING
RATE
GPH
TYPICAL
CHIMNEY
DIMENSIONS
(IN.)
Without
Tankless Coil
With
Tankless Coil
Area
(In.)
Height
(Ft)
A
B
C
BW4AAH000120AAAA
BW5AAH000120AAAA
3
84
74
64
0.60
8 X 8
15
17-3/4
6
9-3/4
3
105
92
80
0.75
8 X 8
15
17-3/4
6
9-3/4
3
140
120
104
1.00
8 X 8
15
17-3/4
6
9-3/4
BW4AAH000181AAAA
BW5AAH000181AAAA
4
126
111
97
0.90
8 X 8
15
21
6
11-3/8
4
175
153
133
1.25
8 X 8
15
21
6
11-3/8
4
210
181
157
1.50
8 X 8
15
21
6
11-3/8
BW4AAH000239AAAA
BW5AAH000239AAAA
5
168
147
128
1.20
8 X 8
15
24-1/4
6
13
5
245
210
183
1.75
8 X 8
15
24-1/4
6
13
5
280
239
209
2.00
8 X 8
20
24-1/4
6
13
*
Heating Capacity is based on a 13 percent CO
2
with a -0.02 in. wc draft over fire and a #1 smoke or less. The testing on boilers was done in accordance with the
Department of Energy (DOE) test procedure.
MBH—1000 Btuh (British Thermal Unit Per Hr)
GPH—Gallons per hour oil at 140,000 BTU per gallon
Shaded areas are as shipped.
A96152
A
19
5
⁄
8
″
GAGE
36
″
1
1
⁄
4
IN.
RETURN
1
1
⁄
4
IN.
SUPPLY
AQUASTAT
CONTROL
(WITHOUT COIL)
AQUASTAT
CONTROL
(WITH COIL)
TANKLESS
HEATER
1
⁄
2
IN.
N.P.T.
9
″
C
B
3
⁄
4
IN.
ASME
RELIEF
VALVE
FRONT
SIDE
REAR
—4—