OPERATION
1.Do not operate heaters at voltages in excess of that stamped on the heater since excess voltage will shorten heater life.
2.Always maintain a minimum of 2” of liquid above the heater to prevent exposure of the effective heated length. If the heater is not properly submerged, it may overheat and shorten heater life. DO NOT OPERATE HEATER IF TANK IS DRY.
3.Be sure all trapped air is removed from a closed tank. Bleed the air out of the liquid piping system and heater housing prior to ener- gizing.
Note: The tank or heating chamber in closed tank systems must be kept filled with liquid at all times.
4.Keep heating elements above sediment deposits.
5.Low Megohm Condition — The refractory materials used in electric heaters may absorb moisture during transit or when sub-
ject to a humid environment. This moisture absorption results in a cold insulation resistance of less than twenty megohms. Normally, this megohm value corrects itself after heatup and does not affect heater efficiency or life.
A low megohm condition can easily be corrected by removing the terminal hardware and terminal enclosure and baking the heater in an oven at 350˚F for several hours, preferably overnight. Note: The lid must be removed from the housing.
An alternate procedure is to energize the heaters at low voltage until the megohm reading returns to normal. When energizing heaters in air, the sheath temperature should not exceed 750˚F.
MAINTENANCE
WARNING: Hazard of Shock. Disconnect all power to heater before servicing or replacing heaters.
1.Heaters should be checked periodically for coatings and corrosion and cleaned if necessary.
2.The tank should be checked regularly for sediment around the heater pipe insert as sediment can act as an insulator and shorten heater life.
3.Remove any accumulated sludge deposits from around pipe and from tank.
4.Check for loose terminal connections and tighten if necessary.
5.If corrosion is indicated in the terminal housing, check terminal box gasket and replace if necessary. Check conduit layout to cor- rect conditions that allow corrosion to enter the terminal housing.
6.Clean terminal ends of all contamination.
