Watlow WATROD Duct Heater (Module Only) - Manual (Page 2)

WATLOW IND.
WATROD Duct Heater (module only) I& M Manual
I&M NUMBER: 316-42-16-1 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 314-221-2816 n FAX 314-221-3723
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.
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.
3. Terminal Enclosures
The product accompanying this manual does not come standard with a terminal enclosure. It is the
customer’s responsibility to provide a terminal enclosure that meets the safety and application
requirements of the specific application. An optional general purpose enclosure is available form the
factory if the user so desires.
Terminal enclosures should be designed to be compatible with the environment in which the heater will
be located. It is the users responsibility to determine the need for correct rating of the electrical housing.
This should be based on appropriate national and local electrical codes. Failure to use a compatible
enclosure could result in heater damage and personnel danger.
The optional terminal enclosure is designed for general purpose use and is rated NEMA 1. These
enclosures should be applied where there will be no danger of spilled liquids, dampness, dirt, and
gaseous conditions.
Units should be located in an area that will minimize the chance of being hit by falling or moving objects.
The terminals must be protected at all times from moisture or vapor.
In order to maintain termination integrity, the terminal enclosure should be kept below 400
°F
(204
°C).
4. Orientation / Mounting
An appropriate full scale cutout with dimensions for the heater module is attached. The duct heater may
be mounted vertically, or horizontally, from the left to right, top or bottom. The inlet side of the unit must
be at least 48" downstream from any transition in duct size or direction, or from any air handling
equipment. Care should be taken to properly support heater module to duct. A support plate can be used
to accomplish this. See Figure 1 for locations that should be avoided.
Heaters may be ganged in parallel for nearly any total wattage desired. The temperature control
thermocouple if so equipped should be located near the work to sense exiting air temperature. Conduct
process temperature sensing in the outlet stream away from the heater.
Minimum air velocity through the heater is 200 fpm for air temperatures approaching 800
°F (412°C).
Lower velocities will jeopardize element life.
Air flow over the entire face of the heater should be uniform at the design velocity.
The units screw or bolt in place through the 9/32" dia. holes in the mounting flange. A 1/4-20 Allen head