A.O. Smith BTH 120-250(A) Installation & Operating Instructions Manual page 24

DANGER
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
TEMPERATURE AT FIXTURES. SEE WATER TEMPERATURE
CONTROL WARNING ON PAGE 4. 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.
TWO TEMPERATURE - ONE HEATER HIGH TEMPERATURE
WITH OR WITHOUT BUILDING RECIRCULATION
*
PIPE RELIEF VALVE TO OPEN DRAIN.
NOTE:
RECIRCULATED, RETURN LINE SHOULD BE
CONNECTED AT POINT "A".
INSTALL IN ACCORDANCE WITH LOCAL
CODES.
IF TEMPERED WATER IS
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