A.O. Smith DB/DW-720-1810 User Manual page 29

TWO DURA-MAX (MODEL DW) HOT WATER SUPPLY BOILERS WITH VERTICAL TANK
Guide To Pipe and Pump Sizing
Two (2) Boiler Systems
Common
Manifold Pipe Boiler Pipe Size
Model Size "A" (Min.) "B" (Min.) and Pump
720, 840 2-1/2"
NPT
960-1810 3"
NPT
Pipe and pump capacities for two (2) boiler systems
based on 100 equivalent feet (30 meters) heater to
tank loop.
TO PREVENT CONDENSATION THE MINIMUM BOILER INLET TEMPERATURE IS 100°F (38°C)
THE INSTALLATION OF SAFETY FLOW SWITCHES AS
SHOWN IS REQUIRED TO PROTECT THE BOILER IN CASE
OF WATER SERVICE INTERRUPTION OR CIRCULATOR
FAILURE.
NOTE: THERMOMETERS, RELIEF VALVES,CIRCULATORS,
SAFETY FLOW SWITCHES AND TANK CONTROLS
ARE AVAILABLE THROUGH A.O.SMITH.
See Table 7
CAUTION
IMPORTANT
FIGURE 22
SEE PAGE 31 FOR ADDITIONAL
PIPING INFORMATION.
CAUTION
PUMP MUST BE RATED FOR SYSTEM OPERATING
TEMPERATURE AND PRESSURE.
* SAFETY RELIEF VALVE RATING SHOULD NOT EXCEED
PRESSURE CAPACITY OF ANY COMPONENT IN THE SYSTEM.
INSTALL IN ACCORDANCE WITH ALL LOCAL CODES.
+ BALL VALVES ARE SHOWN FOR SERVICING BOILER,
HOWEVER, LOCAL CODES SHALL GOVERN THEIR USAGE.
ALL PIPING MUST BE SUPPORTED.