6
7
Thermostat Settings
All residential thermostats are factory
preset at 120°. This is a safe, energy-
efficient setting. If a higher or lower
setting is desired or required, the
thermostat dial may be turned to the
new setting. A flat head screwdriver
may be needed to turn the dial.
Use caution when setting to higher
setting. Scalding can occur.
Therm-O-Disc thermostats have the
temperature settings marked on the
dial. Apcom thermostats do not have
the temperatures on the dial.
Apcom settings:
White Dot
= 110° F
Hot
= 120° F
A
= 130° F
B
= 140° F
C
= 150° F
Very Hot
= 160° F
The settings on both the Apcom and
the Therm-O-Disc thermostats are
accurate to +/- 5° F.
Thermostats
Double Element Water Heaters
The majority of residential water
heaters are designed with two elements
controlled by two different thermostats.
(See drawings on pages 8–9.) The upper
thermostat is the “brain” of the water
heater. It controls the heat generated
by the upper and lower element. Most,
if not all, residential water heaters are
designed to have the upper and lower
thermostats work separately. The lower
element provides the main heat supply.
The upper and the lower thermostats
never operate simultaneously.
The upper thermostat has a safety
device attached to it called a
High Limit
Control (HLC).
It has a heat sensor that
will shut down the power to the heater
if the temperature of the tank exceeds
safety limits. The button may be reset to
restore power to the heater.
Do not reset the HLC until the problem
causing the unit to trip is corrected.
Operation Cycle of Double Element Water Heaters
1. The upper thermostat senses cold
water and has energized the upper
element. Although contacts on both
thermostats are normally closed
in response to the cold water, the
double throw upper thermostat
completes the circuit only to the
upper heating element. Because of
the double throw action, power to
the lower thermostat is cut off.
2. As the upper element operates,
it heats the water above it
(approximately one quarter of the
tank’s capacity).
3. The water in the upper quarter of
the tank is heated until it reaches
the temperature set on the upper
thermostat. The upper thermostat
then breaks the circuit to the upper
heating element and completes the
circuit to the lower thermostat.
4. The lower element then operates and
heats the remainder of the water in
the tank.
5. The lower thermostat breaks the
circuit to the lower element when
the water in the lower portion of
the tank has been heated to its set
temperature. The entire tank is now
filled with hot water.
6. As hot water is drawn from the top
of the tank, cool water comes in at
the bottom through the dip tube.
The lower thermostat reacts to the
entering cold water by closing its
contacts, energizing the lower heating
element and heating the water as it
enters the tank.
7. Thermostats are factory preset
at 120°F.
High watt-density and low watt-density elements are
manufactured with a resistance coil wire imbedded in
a magnesium oxide material covered by copper tubing.
Water heater elements are designed to operate only in
water. Dry-firing (applying power to an element with
inadequate or no water in the tank) raises the internal
and tubing temperatures on the copper element to cause
melt-down of the sheath and failure of the internal heating
resistance wire. The expected life of a dry-fired copper
element is 30-45 seconds. In a dry tank the element
temperature may reach 1900 to 2000° F.
Lime Life elements are manufactured of
premium grade nickel and stainless steel
and will resist dry-firing.
Evidence of Dry-Firing
1. The element shaft is annealed so soft you can bend it
with your fingers.
2. Shows evidence of melting.
3. Plastic terminal block melted, even slightly, indicates
that you have positive proof that element was dry-fired.
An immersion element that has been dry-fired has
been misused and therefore is not covered by any
manufacturer’s warranty.
NOTE: A melted sheath can also be caused by
an electrical storm, which is obviously not a
defect in material or workmanship and is therefore
not covered by warranty.
Dry-Fired Elements
Dry-fired means the element operated without being
immersed in water.
We bring this to your attention with the hope that
it will be of some value to you, as it might avoid the
cost and effort of returning the elements.
1
2
4
3
Exhibit A
Element Conversion Kit
Use a standard screw-in element to replace a flat,
universal or round flange element using the Element
Conversion Kit.
This adapter kit is intended for use with a screw-in type
element to replace water heater elements that look like
figures 1, 2 or 3.
Directions:
1. Remove screws and discard old element
and thermostat bracket.
2. Install screw-in element and gasket supplied with element
into square adapter flange. Tighten firmly.
3. Install gasket (supplied with this kit) in element seat, being
careful to ensure a good seat. See diagrams above to
determine which gasket to use.
4. Install element with new thermostat bracket using old
screws or new ones provided. Be careful that screws
are not too long and bottom out against the tank.
Fig. 1: Universal
Fig 2: Flat
Fig 3: Round
Element Removal
A long socket wrench is needed to remove and install the
Screw-in style elements. The Camco element wrench
(#09943, 09951, 09883) is designed specifically for the
standard and the Duron screw-in elements.
Replacement gasket goes here.
Apcom Style
Therm-O-Disc Style
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