Rheem 20 User Manual

Electric Commercial Water Heaters are suitable for general commercial hot water 
applications and are also ideal for point-of-use installations. Small volume ASME 
models are designed to meet engineering specifications.

immersion thermostat models employ
an element diagnostic panel, utilizing
light emitting diodes (L.E.D.), corre-
sponding to the number and location
of each heating element. This system
monitors the on-off function of the
electric heating elements.

proprietary steel formulation with
high temperature porcelain enamel 
to maximize corrosion resistance
resulting in a superior tank design.

separate screw-in type elements
feature a stainless steel outer sheath
of INCO-LOY 840, surrounding a
Nichrome wire filament, to resist water
chemical corrosion and burn-out even
in air or sediment…for long element
life and long life performance.

Elements are directly immersed in the
water for maximum recovery efficiency
(98%) and are easily changed by
simply screwing new ones into the
tank. LIFEGUARD elements feature
a three (3) year limited warranty.

85% of the tank surface area on all
Rheem-Ruud Commercial Electric
products are insulated with 2-1/2" of
rigid polyurethane foam insulation
providing superior insulating qualities.
Unlike other designs, Rheem-Ruud
Commercial Electrics can achieve 85%
because of the unique compact layout
of the heating elements. This results
in heat losses less than the energy
used by a 75 watt light bulb during
a 48 hour standby period!

• Efficiency – in accordance with ANSI test procedures, these models tested below

the maximum allowable standby loss levels of ASHRAE Standard 90.1b-2001 
(Part of the Federally mandated Energy Policy Act (EPact)). Also exceeds energy
efficiency codes of all states including California Energy Commission (CEC).

• Safety and construction – These products are design certified by Underwriters

Laboratories (UL) to meet UL standard 1453 as electric booster and commercial 
storage tank water heaters. All models are North Carolina and Massachusetts code
compliant. CERTIFIED FOR A 160 PSI MAXIMUM WORKING PRESSURE.

• ASME construction – standard on E12A, E20A, E30A, and E40A models.

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