7
CONSTRUCTION
TANK
The storage tank is designed, manufactured, and stamped in accordance with ASME Section
VIII Division 1. The tank is constructed of type 316L stainless steel and fabricated by all
welded construction and is designed for a maximum allowable working pressure of 150 psi
(225 psi test pressure). As an option, the rear head may be a bolted flange connection that can
be removed to facilitate internal inspection and cleaning of interior tank surfaces.
TANK CONNECTIONS
The heater is supplied with separate connections for the cold inlet and the hot water outlet.
Water entering the cold water inlet and leaving through the hot water outlet is evenly circulated
by means of a diffuser within the tank. A ¾-inch FNPT connection is provided for mounting a
combination safety temperature and pressure relief valve. An overflow line should be utilized
from the relief valve outlet to a floor drain. See drawing for locations and sizes.
HEATING ELEMENT
The water heater is supplied with an electric
immersion heating element assembly(s), composed of
316L stainless steel sheathed elements that are fitted into a 316L stainless steel 1½-12UNF
screw plug with 1-7/8” hex. The element wetted surfaces are passivated and electropolished.
Each assembly is threaded into the tank and sealed with #220 Viton o-ring gaskets. See drawing
for voltage and power ratings.
MAGNETIC CONTACTOR
The definite purpose magnetic contactor(s) is a heavy-duty resistive
load type. The contactor supplies power to the heating element(s)
based on the resistive load (non-inductive) of the heater only when
the relay on the control board is closed, thereby pulling in the
contacts until the desired temperature is reached. At this point, the
contacts will drop out, which in turn disconnects power from the
elements. Units with two contactors will turn on and off in stages.
CONTROL BOARD AND DISPLAY
The control board supplies all the
necessary functionsfor heater operation.
These include control temperature, hi-
limit cut-out, low water detection, and
leak detection.
LOW VOLTAGE CONTROL TRANSFORMER
A control circuit transformer is supplied with all models rated
greater than 240-volts. This component is used to step down the
primary power supply (600, 480, 440, 415, 380, or 277) to 208/240-
volts for safety when working with control circuits.
POWER CIRCUIT BREAKERS
When required by code, a magnetic power circuit breaker is
supplied for circuit overload protection. The circuit breaker can
be reset in the event of a current overload.
OUTER SHELL, INSULATION, AND SUPPORTS
The tank is encapsulated in high efficiency CFC/HCFC free closed cell foam insulation meeting
the requirements for UL 94 HF-1 rating. The protective shell is constructed of type 304 brushed
stainless steel. NSF approved adjustable plastic legs are provided for support.
LOW WATER CUTOUT
A float type 316L stainless steel low water cutout is included for low water detection.
