WATLOW IND. WATROD Circulation Heater Installation & Maintenance Manual
I&M NUMBER: | 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.
•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 could affect you and the equipment
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. Both of these methods should be performed with the heater out of the tank. The orientation of the heater in relation to the tank should be observed in order to reposition the heater properly. This is especially important if a high limit thermocouple is provided.
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
