A.O. Smith HW 300 Installation & Operation Manual page 37

THREE HW-520's, HW-610's OR HW-670's UP-FLOW MODEL
COMMERCIAL BOILER WITH VERTICAL TANK, CER-TEMP 80
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.
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.
USE THIS TABLE FOR CORRECT
PUMP AND WATER PIPE SIZE
Minimum
Pipe Size
Model
(Inches)
Number
A
HW-520 2-1/2"
HW-610/670 3"
* Assumes 50 equivalent feet of piping or less.
FIGURE 32.
DANGER
B & G
*Armstrong
Pump
Pump Size
Size
B
1-1/2" 2" S-45 2-1/2"
1-1/2" 3" HD-3
37
WIRING - FIGURES 21 to 27 on
pages 28 to 32.
INSTALL IN ACCORDANCE
WITH ALL LOCAL CODES
S-46