IMMERSION HEATING ELEMENTS
FIG. 14 Immersion Heating Element
WARNING:
HAZARD OF ELECTRICAL SHOCK - Before opening the access panel to remove or service the immersion heating elements, make sure the electrical supply to the water heater is turned "OFF". Failure to do this could result in death, serious bodily injury or property damage.
The heating input to this commercial electric water heater is provided by low watt density immersion heating elements. The heating elements are constructed from a copper sheath with a tin plate on the exterior surface. Individual element blades are mounted on a hex-head screw-in mounting flange. The element flange mounts into a 1" NPT threaded connection welded to the storage tank. The hex-head screw-in mounting flange seals to the tank with an "O" ring gasket at the base of the threaded portion of the flange. The tank flange has a matching recess for the "O" ring gasket to insure a proper water tight seal. The "O" ring element gasket must be replaced with a new gasket when an element is removed for inspection, cleaning or replacement.
DANGER
HAZARD OF ELECTRICAL SHOCK - Full power is present whenever the cabinet door is opened and main power is turned "ON".
START-UP PROCEDURE
Never operate the heating elements without being certain the water heater is filled with water and a temperature and pressure relief valve is installed in the relief valve opening on top of the heater.
DANGER
Full power is present whenever the cabinet door is opened.
THERMAL EXPANSION
Many water systems are equipped with pressure reducing valves, check valves or back flow preventers which may cause the water system to be closed. As water is heated, it will expand in volume due to thermal expansion. The system must make allowance for this expansion. If an expansion tank is not provided in the system, water pressure may increase to the point where the water heater's temperature and pressure relief valve opens to relieve the excess pressure. The temperature and pressure relief valve is not intended for the constant relief of thermal expansion. This is an unacceptable condition and must be corrected. A properly sized expansion tank is typically installed in the potable water system to relieve the pressure built up by thermal expansion of heated water. Consult your local plumbing contractor and plumbing wholesaler for assistance in properly selecting an expansion tank for your system.
As the water heater operates, there may be noises generated by the expansion and contraction of the metal parts of the water heater and related piping. These noises may occur during periods of heat up or cool down. They do not represent harmful or dangerous conditions.
FILLING THE WATER HEATER
1.Insure that the electrical power to the water heater is in the "OFF" position. If the power disconnect point is out of sight, lock it in the open ("OFF") position and tag to prevent unexpected application of power.
2.Close the water heater drain valve(s).
3.Open a nearby hot water faucet to allow the air in the system to escape as the tank fills.
4.Fully open the cold water inlet valve to the water heater to begin filling the heater and piping.
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