Watlow WATROD & FIREBAR - Manual (Page 2)

WATLOW IND.
WATROD & FIREBAR® Installation & Maintenance Manual
I&M NUMBER: 316-42-7-1 Page: 2
Date:6/11/2008 Rev: 2.00
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WATLOW IND.n # 6 INDUSTRIAL LOOP RD. n HANNIBAL MO, 63401n PHONE 573-221-2816 n FAX 573-221-3723
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; 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 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.
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