A.O. Smith HW 300 Installation & Operation Manual page 34

ONE HW-300, HW-399, HW-420, HW-520, HW-610 OR ONE HW-670 UP-FLOW MODEL
IMPORTANT
THE INSTALLATION OF SAFETY FLOW SWITCH AS SHOWN
IS REQUIRED TO PROTECT THE BOILER IN CASE OF WATER
SERVICE INTERRUPTION OR CIRCULATOR FAILURE.
+ PIPING AND FITTINGS BETWEEN GATE VALVES AND
BOILERS SHOULD BE BRASS OR BRONZE. OTHER
PIPING SHOULD CONFORM TO LOCAL CODES.
GATE VALVES ARE SHOWN FOR SERVICING BOILER.
HOWEVER, LOCAL CODES SHALL GOVERN THEIR USAGE.
* PRESSURE RELIEF VALVE RATING SHOULD NOT
EXCEED PRESSURE CAPACITY OF ANY COMPONENT
IN THE SYSTEM.
** INSTALL THERMOMETER AND PRESSURE RELIEF IN
OPENINGS PROVIDED ON HW-520, HW-610 & HW-670.
COMMERCIAL BOILER WITH HORIZONTAL TANK
WIRING - FIGURES 16 and 17 on
pages 24 and 25.
INSTALL IN ACCORDANCE
WITH ALL LOCAL CODES
USE THIS TABLE FOR CORRECT
PUMP AND WATER PIPE SIZE
Minimum
Model
Pipe Size
Number
(Inches)
HW-300 1-1/4"
HW-399 1-1/2"
HW-420 1-1/2"
HW-520 1-1/2"
HW-610/670 2"
* Assumes 50 equivalent feet of piping or less.
FIGURE 29.
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE
TEMPERATURE AT FIXTURES. SEE TANK TEMPERATURE
CONTROL WARNING ON PAGE 11. IF HIGHER PREHEAT
TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE
BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
B & G
*Armstrong
Pump
Pump Size
Size
125 S-25 1-1/4"
1-1/2" HV H-32 1-1/2"
1-1/2" HV H-32 1-1/2"
1-1/2" HV H-32 1-1/2"
2" S-35
34
DANGER