Watlow Electric 316-42-5-1 manual Terminal Enclosures, Orientation / Mounting

WATLOW IND. WATROD Circulation Heater Installation & Maintenance Manual

I&M NUMBER: 316-42-5-1	Page: 2
Date: 6/11/2008	Rev: 2.00

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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.

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 used.

In order to maintain termination integrity, the terminal enclosure should be kept below 400°F (204°C).

4.Orientation / Mounting

Furnish adequate space for horizontal or vertical installation. Space should be allowed for immersion heater removal from tank.

Approved methods for installation of air (gas) and liquid units are shown in Figures # 1 and # 2. Take careful note of the inlet and outlet locations. Positions other than shown are not recommended.

Figure # 3 shows the preferred position of the circulation heater when pumping liquid from a tank through the heater. The NPSH (Net Positive Suction Head) is one of the most important factors when determining the location of the heater.

WATLOW IND.n # 6 INDUSTRIAL LOOP RD. n HANNIBAL MO, 63401n PHONE 573-221-2816 n FAX 573-221-3723