State Water Heaters 301 Series Instruction Manual page 42

POWER SUPPLY CONNECTIONS
Read the requirements for the
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
Power supply connections must be made as follows:
1. Turn off power at the water heater's enable/disable switch and
the breaker that supplies power to the water heater.
2. Remove the junction box cover. See
junction box location.
3. Connect the 120-VAC 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. Wrap electrical
tape around the wire nut and wire end. See junction box
and the wiring diagram
56
Note: If electrical connection is made directly to terminal
block remove black jumper wire before making
connection.
4. Connect the 120-VAC 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
and wiring diagram
56 Figure 67
Note: If electrical connection is made directly to terminal
block, remove the white jumper wire before making
the connection.
5. Connect the ground wire from the power supply to the grounding
lug inside the junction box. See the junction box in
the wiring diagram
Figure 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
Figure 56. Electrical Wiring - Junction Box
ENABLE / DISABLE CIRCUIT
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
heating operation during periods when the building is unoccupied
or there is no demand for hot water.
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 central control
board (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
(page 13) before
Power Supply
(page 42).
Figure 56
(page 8) for
Figure 3
(page 67).
Figure 67
(page 67).
Figure 56
(page 67).
Ground
Terminal
Jumper Wire
L1
Neutral
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. See
Heater Limited Warranty
CONNECTING AN EXTERNAL SUPERVISORY CONTROL
The enable/disable circuit is accessed from the CCB's J17 plug
inside the CCB enclosure; see
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
66).
5. Connect the two field-supplied control wires to pins 1 and 2 on
the CCB J17 plug.
Figure
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 and Temperature Probe
connectors.
8. Route the control wires inside the junction box on the top of the
water heater; see
box. Use an available knock-out to route the wires inside the
junction box.
Figure
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
and
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
8) to locate the UIM.
Note: Whenever the external control opens the set of dry
contacts used, water heating operation is disabled.
Whenever the external control closes the set of dry
contacts used, water heating operation is enabled. A
diagonal line and circle appears over the thermometer
icon on the UIM when water heating operation is
disabled. See the
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. See
(page 76).
42
Commercial Water
(page 76).
(page 8) to locate the
Figure 3
Figure 66
(page 8) to locate the junction
Figure 3
(page 46).
Table 18
Commercial Water Heater Limited Warranty
(page
(page
Figure 3