A.O. Smith DB/DW-720-1810 User Manual page 30

TWO DURA-MAX (MODEL DW) HOT WATER SUPPLY BOILERS WITH HORIZONTAL TANK
TO PREVENT CONDENSATION THE MINIMUM BOILER INLET TEMPERATURE IS 100°F (38°C)
CAUTION
SEE PAGE 31 FOR ADDITIONAL
PIPING INFORMATION.
FIGURE 23
IMPORTANT
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.
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.
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.
See Table 7