APPLICATION TYPE DIAGRAM
SEE INSTALLATION MANUAL FOR
COMPLETE INSTRUCTIONS
INSTALL IN ACCORDANCE WITH LOCAL CODES.
TYPICAL PIPING FOR CONVENTIONAL
SINGLE BOILER INSTALLATION
HW-300 thru HW 670
SYSTEM NOTES:
• The System Pump must be sized to maintain the minimum
recommended flow rate through the boiler. The pump must
operate continuous or cycle with the boiler.
• The By-Pass is required for systems designed to operate at
flow rate higher than the maximum recommended flow rate
of the boiler.
• This piping method is not recommended for systems designed
to operate with return water temperatures less than 110°F. (See
recommended piping method for Low Temperature Heating Systems
A&E Page E 112.0.)
* PIPE RELIEF VALVE TO OPEN DRAIN.
Model Inlet / Outlet
Size
HW-300 1 1/4" 23 8.0 15 3.0 11 2.0
HW-399 1 1/2" 30 16.0 20 7.0 15 5.0
HW-420 1 1/2" 32 18.0 21 8.0 16 5.5
HW-520 2" 39 12.0 24 5.0 20 4.0
HW-670 2" 51 22.0 34 10.0 25 5.5
20° Temperature Rise 30° Temperature Rise 40° Temperature Rise
GPM PD-Ft/hd GPM PD-hd GPM PD-Ft/hd
June 2007R
Revised June 1998 (Reviewed March 1999) © A. O. SMITH CORP. 1998 Printed in the U.S.A. E 107.0