4
CLEARANCES
A minimum clearance of 4” must be allowed for access to
replaceable parts such as the thermostats, drain valve and relief
valve.
Adequate clearance for servicing this appliance should be
considered before installation, such as changing the anodes,
etc.
FLOOD WARNING
IF THE HEATER BECOMES IMMERSED IN WATER UP TO OR
ABOVE THE LEVEL OF THE BOTTOM OF THE ELEMENT
DOORS, THE HEATER SHOULD BE EXAMINED BY A
COMPETENT SERVICE PERSON BEFORE IT IS PLACED IN
OPERATION.
CHEMICAL VAPOR CORROSION
Water heater corrosion and component failure can be caused by
the heating and breakdown of airborne chemical vapors. Spray
can propellants, cleaning solvents, refrigerator and air
conditioning refrigerants, swimming pool chemicals, calcium
and sodium chloride, waxes, and process chemicals are typical
compounds which are potentially corrosive. These materials
are corrosive at very low concentration levels with little or no odor
to reveal their presence.
Products of this sort should not be stored near the heater. Also,
air which is brought in contact with the water heater should not
contain any of these chemicals. If necessary, uncontaminated
air should be obtained from remote or outside sources.
ELECTRICAL (GENERAL)
Check the heater model and rating plate information against the
characteristics of the branch circuit electrical supply.
DO NOT
CONNECT THE HEATER TO AN IMPROPER SOURCE OF
ELECTRICITY.
Contact the heater supplier for conversion
information if necessary.
Voltage applied to the heater should not vary more than +5%
to -10% of the model and rating plate marking for satisfactory
operation.
DO NOT ENERGIZE THE BRANCH CIRCUIT FOR ANY REASON
BEFORE THE HEATER TANK IS FILLED WITH WATER.
DOING
SO WILL CAUSE THE HEATING ELEMENTS TO BURN OUT.
The factory wiring is attached to a terminal block within external
junction box unit. The branch circuit is connected to terminal
block within this junction box. The water heater should be
connected to a separate, grounded, branch circuit with overcurrent
protection and disconnect switch. The water heater should be
grounded in accordance with national and local codes.
BRANCH CIRCUIT
The branch circuit wire size should be established through
reference to the latest edition of NFPA-70, the
National Electrical Code or other locally approved source in
conjunction with the heater amperage rating. For convenience,
portions of the wire size tables from the Code are reproduced
here. It is suggested the electrician size the branch circuit at 125
percent of the heater rating and further increase wire size as
necessary to compensate for voltage drop in long runs.
CALCULATING
AMPERAGE/OVERCURRENT PROTECTION
The heaters come from the factory in two configurations:
1. Two wire C-2 circuit for single element heater equipped with
a high limit control, single phase power input.
2. Four wire A-8 circuit for dual element heater equipped with
two high limit controls, single phase or three phase power
input.
The heater with dual elements is factory wired for connection to
a three wire, three-phase delta branch circuit, non-simultaneous
operation. In addition a ground conductor is required.
Element connection is for non-simultaneous operation. This
means only one element at a time operates. The wiring diagram
(on page 5) shows the heater may be field converted to
simultaneous element operation by moving the red wire on
“J” terminal to L1. It is then possible for both elements to operate
at once as determined by the thermostats. Regardless of
element connection the heater operates in an “unbalanced”
fashion.
The heater may be field converted to single-phase operation by
moving the wire on L3 of the terminal block to L2. L3 is not
used. (See page 5).
The heater, now in single-phase non-simultaneous operation,
may be field-converted to single phase simultaneous operation
by moving the red wire on terminal “J” to L1, refer to wiring
diagram on page 5.
This is an example of calculating heater amperage for both
types of element operation. From this, the branch circuit
conductor and overcurrent protection sizing can be established.
The example is of a three-phase 240 volt unit with two, 6 kw
elements. The notations are for units field converted to
single-phase. Check the heater model and rating plate for actual
specifications and substitute those values in the following.
Non-simultaneous:
Simultaneous:
(as factory wired)
(Field conversion)
3000 : 240 = 12.5 amps*
3000 : 240 = 12.5 amps*
12.5 x 1.73 = 21.6 amps
*NOTE: as a single-phase
*NOTE: as a single-phase
non-simultaneous unit.
simultaneous unit the
total is:
12.5 x 2 = 25 amps
The rating of the overcurrent protection should be computed on
the basis of 125 percent of the total connected load amperage.
Where the standard ratings and settings do not correspond
with this computation, the next higher standard rating or setting
should be selected.
Portion of Table 310-16 follows:
Allowable Ampacities of Insulated Copper Conductors. Not
more than three conductors in Raceway or Cable or Direct Burial
(Based on Ambient Temperature of 30° C, 86° F).
These ampacities relate only to conductors described in Table
310-13 in Code.
