WATLOW ELECTRIC MFG CO.
WATROD Flange Heater Installation & Maintenance Manual
I&M NUMBER: 316-42-8-1 Page: 2
Date:11/20/2013 Rev: 6.00
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used.
procedures or to wrap this section with a flexible heater. The cover of the enclosure should be removed
or opened slightly so the temperature may be monitored and maintained at below 200°F. Ensure that the
insulation on the standoff section is removed before the heater is placed into operation
.
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. Over temperature devices should interrupt or remove power from heater circuit. Watlow
recommends that all temperature limit devices have appropriate third party approval. Be sure that all
temperature limiting devices are connected to appropriate controls independent of the process
temperature control. Be sure heater is installed in the correct orientation. Hi limit sensor and baffle
orientation (if so equipped) is critical.
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 meltdown of a heater, and / or
damaging fire. Perform functional test of all temperature limiting devices on a regular interval.
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 order 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. Terminal Enclosures
Terminal enclosures should be selected 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.
Standard terminal enclosures are designed for general purpose use and are rated NEMA 1. These
enclosures should be applied where there will be no danger of spilled liquids, dampness, dirt, and
gaseous conditions. Enclosures for wet or hazardous locations are also available, but must be installed
at the factory.
Although enclosures are supplied over the terminals, 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 hazardous locations, (as defined in NFPA 70 NEC, Article 501) explosion resistant housings must be
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