A.O. Smith BTH 120-250(A) Installation & Operating Instructions Manual page 27

TEMPERATURE SETTING SHOULD NOT EXCEED SAFE TEMPERATURE
AT FIXTURES. SEE WATER TEMPERATURE CONTROL WARNING ON PAGE
5. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN
ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT
WATER SUPPLIED TO FIXTURES.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACK-FLOW
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
TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE
WITH RECIRCULATION OF SANITIZING LOOP
DANGER
NOTE 1: TOGGLE SWITCH CONTROLS 180°F (82°C) WATER CIRCULATION.
INSTALL ON OR CLOSE TO DISHWASHER. TOGGLE SWITCH MUST BE
CLOSED (ON) DURING THE RINSE OPERATION AND OPEN (OFF) WHEN
DISHWASHER IS NOT OPERATING OR WHEN ON LONG STANDBY.
NOTE 2: INSTALL LINE TEMPERATURE CONTROL IN AN UNINSULATED
TEE BEYOND THE DISHWASHER TAKEOFF IN THE SANITIZING LOOP.
CONTROL SHOULD BE SET AT 185°F (85°C).
NOTE 3: ADJUST PLUG COCK SO THE SANITIZING LOOP FLOW RATE
DOES NOT CAUSE UNNECESSARY TURBULENCE IN THE TANK.
NOTE 4: IF TEMPERED WATER IS RECIRCULATED, RETURN LINE SHOULD
BE CONNECTED AT POINT A.
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