A.O. Smith BTR120 Installation Operation & Maintenance page 21

MEDIUM TEMPERATURE - ONE HEATER WITH AUXILIARY STORAGE TANK
FORCED CIRCULATION WITH OR WITHOUT BUILDING RECIRCULATION
* PIPE RELIEF VALVE TO OPEN DRAIN.
**WHEN USING AN A.O. SMITH T-140, -
200,
-350 OR -400 STORAGE TANK, USE
LOWER 3/4" OPENING FOR TANK
TEMPERATURE CONTROL.
IF BUILDING CIRCULATING LOOP IS
USED, CONNECT TO AN OPENING NEAR
THE BOTTOM OF THE TANK.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A
BACKFLOW PREVENTER, CHECK VALVE OR WATER
METER WITH CHECK VALVE. PROVISIONS FOR
THERMAL EXPANSION OF WATER IN THE HOT WATER
SYSTEM MUST BE PROVIDED.
*PIPE RELIEF VALVE TO OPEN DRAIN
INSTALL IN ACCORDANCE WITH LOCAL CODES.
VERTICAL STORAGE TANK
HORIZONTAL STORAGE TANK
21
DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
USE TEMPERATURE AT FIXTURES. SEE WATER
TEMPERATURE CONTROL WARNING ON PAGE 27. IF
HIGHER PREHEAT TEMPERATURES ARE NECESSARY
TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN
ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO
FIXTURES.