A.O. Smith SERIES 100 Installation & Operating Instructions Manual page 30

CAUTION: IF THE PLUMBING
REQUIRES THE USE OF PIPES
WITH DISSIMILAR MATERIAL (FOR
EXAMPLE, STEEL AND COPPER),
USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALVANIC
ACTION BETWEEN THE PIPING
COMPONENTS WITH DISSIMILAR
MATERIALS.
TWO TEMPERATURE - THREE HEATERS (TWO PRE-HEATERS/ONE BOOSTER HEATER)
MUST BE IDENTICAL HEATERS
FOR MULTIPLE HEATER INSTALLATION SEE MANIFOLD KIT
SPECIFICATIONS, PAGE 33.
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 - TWO HEATERS HIGH TEMPERATURE
WITH OR WITHOUT BUILDING RECIRCULATION
WITH OR WITHOUT BUILDING RECIRCULATION
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.
30
CAUTION: IF THE PLUMBING
REQUIRES THE USE OF PIPES
WITH DISSIMILAR MATERIAL (FOR
EXAMPLE, STEEL AND COPPER),
USE DIELECTRIC UNIONS TO
PREVENT AN ELECTRO-GALVANIC
ACTION BETWEEN THE PIPING
COMPONENTS WITH DISSIMILAR
MATERIALS.
DANGER