SER
VICE
Electric Tankless Water Heater •
25
Disconnect all branch circuits
before servicing unit.
•
Check wires with a non-contact
circuit tester to make sure power is
o
ff
. When you are
fi
nished, be sure
all covers are secured to reduce the
risk of
fi
re and electric shock.
If you are not comfortable replacing
a thermistor yourself, have this work
done by a quali
fi
ed person. To replace
a thermistor, you’ll need the following
tools/supplies:
•
Phillips head screwdriver
•
1/2-inch open end wrench
•
Bucket (for draining the heater)
•
Siphon transfer pump & towels
1
Turn o
ff
power to the water
heater.
2
Drain the water heater as
described in the draining
instructions (page 27).
3
Locate the thermistor (tem-
perature sensor) that was
iden
fi
ed by the error code.
Refer to the appropriate
fi
gure on page 26.
Figure 21.
Top vi
Thermistor
4
Unplug the thermistor’s wires
from the control board.
Continued on page 27.
7.3 Install the new element:
A.) Insert the new element into its
water heater opening.
Make
sure that the O-ring is positioned
properly.
(See Figure 20.)
Figure 20.
O-ring
B.) Tighten the element with an
element wrench until it is snug,
then tighten for 1/4 turn more.
C.) Secure the red and black wires
onto the top of the heating
element. Use the two screws that
you removed earlier. Proceed to
step 8.
8
Turn on the
WATER
supply to
the heater.
9
Turn on a nearby hot water fau-
cet to fill the heater with water.
Continue until all air has been
expelled from the heater and pipes. If a
T&P valve is installed, operate it
manually several times to allow any
trapped air to escape.
10
Check for water leaks. Correct
any leaks that are found.
NOTICE: Do not restore power until
the circuit board and components are
completely dry.
If water has dripped
anywhere inside the heater (during ele-
ment replacement or leak check), dry it
with a hair dryer or compressed air.
Be
sure to dry behind the circuit board.
11
If there are no water leaks,
complete these steps:
A.)
Two- or four-chamber water
heaters only:
Take the connector
end of the cover’s ribbon cable
and plug it into the control board.
(Plug it in where you see two rows
of header pins close together, five
pins in each row.) If necessary,
refer to the “DISPLAY” callout
in the wiring diagram for your
model. (See “Wiring Diagrams” on
page 29.)
NOTICE:
The plug must be oriented
correctly. (The correct orienta on
is shown in Figure 5, page 14.)
If you plug it in backwards, it will
not cause damage, but the display
will not work. If the display does
not work a er you have completed
installa on, 1.) disconnect power
at all branch circuits, 2.) disconnect
the plug, 3.) rotate it 180-degrees,
then 4.) plug it back in.
B.) Reinstall the water heater’s cover.
WARNING! Be sure the cover is
reinstalled and secured to reduce
the risk of fire and electric shock.
C.) Restore power to the water
heater.
D.) Run hot water from a faucet to
make sure that the water heater
is working as expected.
Thermistor
(Temperature Sensor)
Replacement
WARNING!
•
Working on an energized circuit
can result in severe injury or
death from electrical shock. Turn
power off.
•
Some models are connected to
more than one branch circuit.
