Operating instructions

BOILER RATINGS AND CAPACITIES
The ratings marked "Net I=B=R Rating" indicate the amount of radiation each boiler will take care of under normal conditions and thermostatic
control. The Net I=B=R Ratings shown are based on an allowance of 1.15 in accordance with the factors in the I=B=R Standard as published by
The Hydronics Institute.
Selection of boiler size should be based upon "Net I=B=R Rating" being equal to or greater than calculated heat loss of building.
Consult manufacturer before selecting a boiler for installations having unusual piping and pickup requirements.
These boilers must stand on a non-combustible floor. If installed on a combustible floor, a factory-approved combustible floor base must be used.
Specifications and dimensions are subject to change without notice.
BOILERS FOR USE AT HIGH ALTITUDE
This boiler is factory equipped for use at altitudes of 0-2000 ft above sea level. For use at altitudes above 2000 ft above sea level, input ratings
are reduced by a change in main burner orifice size.
For altitudes above 2000 ft above sea level, input ratings should be reduced at the rate of 4% for each 1000 ft above sea level. Consult the NFGC
NFPA 54/ANSI Z223.1-1992 or the manufacturer for correct orifice sizing. High-altitude orifices are available from boiler manufacturer.
INTRODUCTION
This boiler cannot be used with all types of chimneys. Read these instructions carefully before installing.
These Gas-Fired Hot Water Boilers are low-pressure, sectional cast iron boilers design certified by the American Gas Association (A.G.A.) for
use with natural and propane gases. They are 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.) Boiler and Pressure Vessel Code Section IV Standards for cast iron heating boilers.
Check to be sure boiler size is correct before starting installation. See rating and capacity table shown in Fig. 1. Also be sure new boiler is for
the type of gas being used. Check rating plate on right side of boiler.
The boiler must be supplied with correct type of gas, fresh air for combustion, and a suitable electrical supply. Boiler must also be connected to
a suitable venting system and an adequate piping system. Finally, a properly located thermostat is needed for control of heating system. If there
are any doubts as to the various requirements, check with local authorities and obtain professional help where needed. Take time to complete all
the steps for SAFE and PROPER operation of heating system.
Fig. 1—Dimensional Drawing and Boiler Ratings and Capacities
Gas-Fired Hot Water Boilers
BOILER MODEL NUMBER*
NO. OF
SECTIONS
NATURAL AND PROPANE GAS† DIMENSIONS (IN.)
A.G.A.
Input
MBH
Heating
Capacity
MBH
Net
I=B=R
Rating
MBH
Width Vent Diameter
A
To Chimney
(Category I)
BW3AA-000042AAAA 2 42.5 36 31 11 4
BW3AA-000075AAAA 3 75.0 63 55 14-1/4 4
BW3AA-000112AAAA 4 112.5 94 82 17-1/2 4
BW3AA-000150AAAA 5 150.0 125 109 20-3/4 4
BW3AA-000187AAAA 6 187.5 155 135 24 4
BW3AA-000225AAAA 7 225.0 186 162 27-1/4 4
* Sixth position of Model No. indicates natural or propane gas usage: N = Natural Gas
P = Propane Gas
† Boilers are equipped for altitudes up to 2000 ft only. For altitudes above 2000 ft, ratings should be reduced at the rate of 4% for each 1000 ft above sea level. Heating
Capacity is based on Department of Energy (D.O.E.) test procedure.
MBH—1000 Btuh
Btuh—British Thermal Unit Per Hour
A85084
29″
23″
25
1
⁄
4
″
23
1
⁄
4
″
5
5
⁄
8
″ 5
5
⁄
8
″
1
3
⁄
4
″
7
3
⁄
8
″
8
1
⁄
2
″
A
GAS
VALVE
INT. PILOT
CONTROL
PRESSURE
SWITCH
BLOWER
VENT
CONNECTOR
COMBINATION
LIMIT & RELAY
CONTROL
1
1
⁄
4
″ SUPPLY
RELIEF
VALVE
BURNER
TEMP
PRESSURE
GAGE
1
1
⁄
4
″ RETURN
CIRCULATOR
LEFT SIDE RIGHT SIDEFRONT
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