Watlow WATROD Screw Plug - Manual

WATLOW IND.
WATROD Screw Plug Installation & Maintenance Manual
I&M NUMBER: 316-42-10-1 Page: 1
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
Pre Installation
• Check to make sure that heater received is the same as that ordered.
• Elements may come in contact with each other during shipment. Minor adjustments to elements may be
required prior to installation to separate them. Extensive bending of elements should be avoided since
dielectric strength between coil and sheath may be compromised.
• Watlow heaters are built to comply with UL, CSA, and CE LVD dielectric requirements, it may be necessary
due to atmospheric conditions / humidity, to perform a dielectric test prior to startup. (Refer to megohm
test under Installation section)
Safety
Electric heaters are inherently dangerous!! Care should be taken to read and completely understand the
Installation and Maintenance manual before installing and wiring the heater. Any installation and maintenance
performed on the heater shall be done by a qualified electrician, in accordance with the "National Electric
Code" and other electrical codes as they apply. It is the users responsibility to ensure that the heater being
used is properly selected and installed in the application.
!
The Caution Symbol (exclamation point) alerts you to a "CAUTION", a safety or
functional hazard which could affect your equipment or its performance.
The warning symbol (lightning bolt) alerts you to a "WARNING", a safety hazard which could
affect you and the equipment
Installation
Proper heater selection and installation will result in efficient heat transfer, safe operation, and long heater life.
1. Megohm precheck
During shipping and/or storage, the possibility of moisture absorption by the insulation material within the
element is possible. To ensure proper megohm values a minimum 500 VDC megohm meter (Megger)
should be used to ensure that the megohm reading between the heater terminal and the heater sheath is
more than 10 megohms when the unit is at room temperature.
If several units are interconnected, the megohm of the heater is obtained by taking the reading and dividing
by the number of interconnected elements. This reading should be greater than 10 megohms.
If a low megohm value exists, two alternative methods can be used to remedy the situation. The best
method is to remove all terminal hardware including thermostat if provided, and bake out the heater at no
higher than 250°F (120°C) overnight or until an acceptable reading is reached. The second method is to
energize the unit at low voltage in air until the megohm is at an acceptable reading. Care should be taken
to prevent the heater sheath from exceeding 750°F (398°C) for INCOLOY or equivalent elements, 750°F
(398°C) for carbon steel elements, and 400°F (204°C) for copper elements.
2. Protection of heater elements from over temperature
The use of temperature controls to regulate heating process and prevent heater over temperature is highly
recommended to ensure safe heater operation. It is the users responsibility to ensure safety of the
installation.
WARNING: Install high temperature control protection in systems where an over temperature fault
condition could present a fire hazard or other hazard. Failure to install temperature control
protection where a potential hazard exists could result in damage to equipment and property, and
injury to personnel.