41
heating operation during periods when the building is unoccupied
or there is no demand for hotwater.
To use the enable/disable circuit it must first be activated by
selecting the “Use External Enable” from the UIM. Field supplied
wiring is then installed between the water heater’s CCB and a
set of “dry contacts” (no voltage or load) on the field supplied
external control.
NOTE:
The water heater’s enable/disable circuit is a switching
circuit only: Do not apply external voltage or connect any load
(IE: relay coil) to this circuit. This will damage the CCB circuit
board and is not covered under the limited warranty.
CONNECTING AN EXTERNAL SUPERVISORY CONTROL
The enable/disable circuit is accessed from the CCB’s J17 plug
inside the CCB enclosure; see Figure 3 on page 8 to locate the
CCB enclosure. Install field wiring to the enable/disable circuit:
1. Turn off power at the water heater’s enable/disable switch
and the breaker that supplies power to the water heater.
2. Locate the CCB enclosure.
3. Carefully remove the Temperature Probe connectors and
CCB enclosure cover.
4. Locate pins 1 and 2 on the CCB J17 plug. See Figure 66 on
page 66.
5. Connect the two field supplied control wires to pins 1 and 2
on the CCB J17 plug.
6. Thread the control wires out of the CCB enclosure with
the other wiring and carefully replace the CCB enclosure
cover. Ensure all wiring is routed through the intended area
provided for strain relief. Ensure no wiring is being pinched.
7. Reinstall the CCB enclosure cover.
8. Route the control wires inside the junction box on the top
of the water heater; see Figure 3 on page 8 to locate the
junction box. Use an available knock-out to route the wires
inside the junction box.
9. Install field supplied control wiring and conduit as required
by national and local codes between the water heater’s
junction box and the external supervisory control. Connect
the wiring from the external control to the control wires inside
the junction box using wire nuts and electrical tape.
10. Connect the control wiring to a set of dry contacts on
the external control. Follow the control manufacturer’s
instructions for making connections.
11. Restore power to the water heater.
12. From the water heaters UIM “Heater Information Screen”
select “Use External Enable” and change to “Yes”. See
Figure 3 on page 8 to locate the UIM.
NOTE:
Whenever the external control opens the set of dry
contacts used, water heating operation will be disabled.
Whenever the external control closes the set of dry contacts
used, water heating operation will be enabled. A diagonal line and
circle appears over the thermometer icon on the UIM when water
heating operation is disabled. See the Status Icons descriptions
in Table 14 on page 46.
NOTE:
Ensure the water heater is protected from freezing
temperatures when water heating operation is disabled. Damage
to the water heater caused by freezing temperatures is not
covered under the limited warranty.
POWER SUPPLY CONNECTIONS
Read the requirements for the Power Supply on page 13
before connecting power.
The 120 VAC hot wire from the power supply must connect to
the black jumper wire or the "L1" terminal block location in the
junction box and the 120 VAC neutral wire must connect to the
white jumper wire or the "Neutral" terminal block location in the
junction box for correct polarity. See Figure 56.
Power supply connections must be made as follows:
1. Ensure the power supply is turned off at the breaker or
disconnect switch.
2. Remove the junction box cover. See Figure 3 on page 8 for
junction box location.
3. Connect the 120VAC hot wire from the power supply to the
black jumper wire or the terminal block location marked
"L1" inside of the junction box located on top of the water
heater. If the black jumper wire is used make the connection
inside of the junction box with a properly sized wire nut and
wrap electrical tape around the wire nut and wire end. See
junction box Figure 56 and wiring diagram Figure 67 on
page 67.
NOTE:
If electrical connection is made directly to terminal
block remove black jumper wire before making connection.
4. Connect the 120VAC neutral wire from the power supply to
the white jumper wire or the terminal block location marked
"Neutral" inside of the junction box located on top of the
water heater. If the white jumper wire is used, make the
connection inside of the junction box with a properly sized
wire nut and wrap electrical tape around the wire nut and
wire end. See junction box Figure 56 and wiring diagram
Figure 67 on page 67.
NOTE:
If electrical connection is made directly to terminal
block remove white jumper wire before making connection.
5. Connect the ground wire from the power supply to the
grounding lug inside the junction box. See junction box
Figure 56 and Wiring Diagram Figure 67 on page 67.
6. Replace junction box cover when connections are complete.
NOTE:
Do not apply power to the water heater before installation
is complete and the water heater is filled with water.
Heater Wiring
(Factory Installed)
MOV
Ground
Ground Terminal
Jumper Wire
L1
Neutral
Figure 56
ENABLE / DISABLE CIRCUIT (For Building
Management Systems)
The water heaters covered in this manual are equipped with
an enable/disable circuit for use with field supplied external
supervisory controls such as time clocks or Building Management
Systems. The enable/disable circuit may be used to disable
