Watlow WATROD FIREBAR User Manual

WATLOW IND. WATROD & FIREBAR



Installation & Maintenance Manual

I&M NUMBER: 316-42-7-1 Page: 1
Date:6/11/2008 Rev: 2.00

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Pre Installation

 Check to make sure that heater received is the same as that ordered.
 Watlow heaters are built to comply with UL and CSA 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

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 a low megohm value exists, two alternative methods can be used to remedy the situation. The best
method is to remove all terminal hardware 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 and 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.

Failure of components in a temperature control loop, such as the sensor, heater control relay or main

temperature control, can result in damage to a product in process, a melt down of a heater, and / or
damaging fire.

could affect you and the equipment

WATLOW IND.n # 6 INDUSTRIAL LOOP RD. n HANNIBAL MO, 63401n PHONE [phone] n FAX [phone]

WATLOW IND. WATROD & FIREBAR



Installation & Maintenance Manual

I&M NUMBER: 316-42-7-1 Page: 2
Date:6/11/2008 Rev: 2.00

________________________________________________________________________________________________________________________________________________________________________________________________________________________

To protect against this possibility, over temperature protection must be provided to interrupt or remove

power from the heater circuit. A bulb and capillary thermostat is not recommended for this function

since it may not respond quickly enough to adequately protect the heater. In cases where the
thermostat bulb gets too hot before the system is turned off, the thermostat bulb could rupture.
This could result in the thermostat remaining in the "ON" condition since there is insufficient
fluid to move contacts apart. We recommend the temperature protection have appropriate third party

approval, and be applied in the classification for which it was tested and approved.

In immersion applications, to help prevent premature failure and a potentially hazardous condition in

cases where consequences of failure may be severe, use an appropriate third party approved liquid level
protection device. The liquid level should be such that the entire heater is fully submerged with enough
liquid above the heater to adequately dissipate heat from itself as under normal operating conditions.
Consult your local authorized sales representative for specific recommendations for your application.

3. Termination / Environment

In order to maintain termination integrity, the termination should be kept below 250F
(121C) or the maximum temperature rating of the end seal. Keep terminations clean, dry and tight.

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.

4. Wiring
WARNING;

grounded to earth to eliminate shock hazard.

Electrical wiring to the heaters must be installed in accordance with the National Electric Code and any

state and local electrical code by qualified personnel.

Line voltage must be equal to or less than rating stamped on the heater assembly.

5. Miscellaneous
For immersion applications, extend the heated section completely into the media being heated at all

times to maximize heat transfer and heater reliability.
Do not locate the end of heated length within a bend unless the radius is 3 inches or longer.
The cold end junction must be located a minimum of one inch from any bend. If these parameters are

not followed, the heater may fail prematurely.

For FIREBAR elements, Watlow does not recommend field bending of the elements. However, if the

element must be bent in the field, please consult your local Watlow sales engineer or authorized

distributor for assistance.

HAZARD OF ELECTRIC SHOCK. Any installation involving electric heaters must be

Start Up

WATLOW IND.n # 6 INDUSTRIAL LOOP RD. n HANNIBAL MO, 63401n PHONE [phone] n FAX [phone]