Watlow WATROD Flange Heater User Manual

WATLOW IND. WATROD Flange Heater Installation & Maintenance Manual

I&M NUMBER: 316-42-8-1 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
and 400°F (204°C) for copper 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

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 Flange Heater Installation & Maintenance Manual

I&M NUMBER: 316-42-8-1 Page: 2
Date:6/11/2008 Rev: 2.00

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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 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

Watlow flange immersion heaters incorporate a standard ANSI flange for universal mounting in tanks

equipped with the same size mounting flange. A suitable gasket and mounting bolts are required for
installation but are not provided with the heater. The correct gasket material should be based on the
material being heated and the process temperature.

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 through the header on the tank, care should be taken to avoid bending the elements. If
possible elements should be inspected to ensure that they are not touching. Failure to do so could result
in shorter heater life due to higher heater temperatures.

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

WATLOW IND. WATROD Flange Heater Installation & Maintenance Manual

I&M NUMBER: 316-42-8-1 Page: 3
Date:6/11/2008 Rev: 2.00

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The location of an immersion heater in a process is of prime importance. To take advantage of natural

convection, the unit should be located as low as possible; similar to the position in Figure 1.
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.

If heater is being installed in customer supplied circulation tank, a Tubular Circulation I&M manual should

be obtained from the factory to ensure safe installation of heater in tank. Failure to do this could result in
premature heater failure due to improper fluid flow over elements

ALLOWANCE FOR
HEATER REMOVAL

LIQUID LEVEL

2" MIN

SLUDGE

ANSI WELD NECK FLANGE
TO MATCH HEATER FLANGE SIZE

Figure # 1

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.

5. 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.

Consult wiring diagram supplied with the unit for correct feeder wires connections. If one is not supplied,

the factory should be consulted for the appropriate wiring diagram. Feeder wire should be properly
selected based on amperage, electrical power rating, ambient temperature, and type of environment.
Feeder wire should also be housed in either rigid or flexible conduit which carries the same classification
as the heater enclosure. It is the users responsibility to properly size and install feeder wire.

Feeder wire line connections may be made directly to stud terminals or box type compression fittings.

Box type compression fittings will accept a #4 AWG maximum wire while stud terminals will accept a
#10 ring connector(T&B, Amp, etc.). It is essential that these connections be tight. Stud terminals should
be tightened to a maximum torque of 20 in-lbs while the bottom nut is supported. Ground connection
(color coded "green") is supplied inside the housing for ground wire.

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