Watlow WATROD Screw Plug - Manual (Page 3)

WATLOW IND.
WATROD Screw Plug Installation & Maintenance Manual
I&M NUMBER: 316-42-10-1 Page: 3
Date:6/11/2008 Rev: 3.00
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WATLOW IND.n # 6 INDUSTRIAL LOOP RD. n HANNIBAL MO, 63401n PHONE 573-221-2816 n FAX 573-221-3723
high limit device is a must for a "Y" mounting orientation together with a liquid level control where fire
and/or physical damage or injury could occur.
If heater is being installed in customer supplied circulation tank, a Tubular Circulation I&M manual should
be obtained from the factory to ensure safe installation of heater in tank. Failure to do this could result in
premature heater failure due to improper fluid flow over elements
SLUDGE
LIQUID LEVEL
2" MIN
FEMALE PIPE COUPLING TO MATCH
SCREW PLUG SIZE
HEATER REMOVAL
ALLOWANCE FOR
"Y" POSITION
"X" POSITION
Figure # 1
DANGER: HAZARD OF FIRE. Electric heaters are capable of developing high temperatures so extreme
care should be taken to locate heaters in safe environments. Mounting heaters in atmospheres containing
combustible gases and vapors should be avoided. According to article 501 of the NEC, the maximum
surface temperature of the heater shall not exceed 80 % of the auto-ignition of the surrounding atmosphere
when the heater is continuously energized. Care should also be taken to keep combustible materials far
enough away to be free of the effects of high temperatures.
5. Wiring
WARNING; HAZARD OF ELECTRIC SHOCK. Any installation involving electric heaters must be
grounded to earth to eliminate shock hazard.
Electrical wiring to the heaters must be installed in accordance with the National Electrical Code, NFPA
70, and any state and local electrical code by qualified personnel.
Consult wiring diagram supplied with the unit for correct feeder or leadwire connections. If wiring diagram is
not supplied, the factory should be consulted for the appropriate wiring diagram. Feeder wire should be
properly selected based on amperage, electrical power rating, ambient temperature, and type of
environment. Feeder wire should also be housed in either rigid or flexible conduit which carries the same
classification as the heater enclosure. It is the users responsibility to properly size and install feeder wire.
Feeder wire line connections are to be made directly to stud terminals. Use a ring terminal (T&B, Amp,
etc.) for making these connections. It is essential that these connections be tight. For 1" and 1¼" NPT the
90º connector should be held with a pair of pliers while the screw is tightened against the ring terminal. For
2" to 2½" NPT units the bottom nut should be supported while applying a maximum torque of 20 in-lbs to
the top nut. Ground connection (color coded "green") is supplied inside the housing for ground wire.
Line voltage must be equal to or less than rating stamped on the heater assembly. Some units are supplied
as dual voltage . Example: 240V / 480V, check wiring diagram supplied with the unit to make sure which
scheme was used. In most cases (unless specified by customer) units are wired for the higher voltage.