Specifications
TM013 Vulcan Electric Service Instructions REV: D 
D.O.I.: 05/09 
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7 
Components and their Function 
Temperature and Pressure Relief Valve 
A  valve designed  to  provide automatic  relief by  discharging  water in  case  of  excessive 
temperature, pressure or both. 
Never fit a T&PR Valve with a pressure rating greater than that indicated on 
the product-rating label. 
Pressure Limiting Valve (P.L.V.) 
A valve that controls its outlet pressure to a predetermined limit.     
Outlet Delivery Tube (Dip Tube) 
A plastic tube installed in the hot water outlet of the water heater cylinder to conduct water 
from the highest point to the outlet connection. It also acts as a fitting liner. 
Inlet Delivery Tube (Dip Tube) 
A plastic tube installed in the cold water inlet of the water heater cylinder to assist with 
stratification. It also acts as a fitting liner. 
Diffuser 
A plastic device installed in the cold water inlet of the water heater cylinder to assist with 
stratification. It also acts as a fitting liner. 
Fitting Liner 
A  plastic  tube  installed  in  the  cold-water  inlet  of  the  water  heater  to  provide  protection 
against corrosion throughout the life of the water heater. 
Anode (Sacrificial) 
A metal alloy electrode installed in the water heater cylinder that by galvanic action 
protects the cylinder from corrosion. 
Thermostat 
A device, responsive to temperature, which controls the supply of electrical energy to the 
element to maintain the stored water at the required temperature. 
Non-simultaneous (Top) Thermostat – Twin Element Models 
A device, responsive to temperature, which controls the supply of electrical energy to the 
top element to maintain the stored water at the required temperature. It also switches the 
neutral supply between the top and bottom elements to ensure only one element can be 
operational at any time. This is known as non-simultaneous operation. 
Over Temperature Energy Cut out (E.C.O.) 
A temperature-sensing device in combination with the thermostat that automatically cuts 
off the supply of electrical energy to prevent excessive water temperature occurring.  This 
device  will  not  reset  automatically  but  may  be  manually  reset  once  temperatures  have 
fallen to a safe level. DETERMINE CAUSE OF OPERATION. 
Heating Unit (Element) 
A tubular device containing an electric resistance element that converts electrical energy 
to heat. Standard ratings are 1.2, 1.8, 2.4, 3.6, 4.8 and 6.0kW. 










