Watlow WATROD Over-the-Side User Manual

WATLOW IND. WATROD Over-the-Side Installation & Maintenance Manual

I&M NUMBER: 316-42-9-1 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.

• Elements may come in contact with each other during shipment. Minor adjustments to elements may be

required prior to installation to separate them. Extensive bending of elements should be avoided since
dielectric strength between coil and sheath may be compromised.

• 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 several units are interconnected, the megohm of the heater is obtained by taking the reading and
dividing by the number of interconnected elements. This reading should be greater than 10 megohms.

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 including thermostat if provided, 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.

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.

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

could affect you and the equipment

WATLOW IND. WATROD Over-the-Side Installation & Maintenance Manual

I&M NUMBER: 316-42-9-1 Page: 2
Date: 6/11/2008 Rev: 2.00

________________________________________________________________________________________________________________________________________________________________________________________________________________________

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.

Over-the -side heaters are susceptible to damage due to fluctuation of tank level. 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 on "L" ,"O", and Vertical loop heaters are supplied with enclosures rated

for NEMA 4 applications. The drum Over-the-side heaters are supplied with NEMA 1 general purpose
enclosures. 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 for
the drum Over-the-side heaters 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.

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

Heater orientation is important in order to ensure efficient heat transfer and safe operation. Care should

be taken to allow enough room for heater expansion without compromising heat transfer. When installing
the heater into the tank, be sure that the heater is stable and setting solidly on the tank bottom or being
held to the tank wall rigidly. Consideration should also be given to sludge build-up in the bottom of the
tank and the need for heater removal (replacement or maintenance). Location of the heater in the sludge
area will cause premature failure and lower heat transfer efficiency.

Figure # 1 shows the proper location in relation to the liquid level in the tank for proper installation.
The heated section of the Over-the-Side heater must be immersed during operation or premature

failure may result. The use of an approved high limit device is highly recommended, together with a
liquid level control where fire and/or physical damage or injury could occur.

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