PV500-57 06/12
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Since low water cut-off devices are generally set by the original manufacturer, no attempt should be made to
adjust these controls to alter the point of low water cut-off or point of pump cut-in or cut-out. If a low water
device should become erratic in operation, or if it’s setting changes from previous established levels, check for
reasons and correct, repair, or replace as required.
6. The standard low water control on hot water supply boilers is electronic. Periodically press the electronic low
water cutoff test switch to confirm proper operation.
WARNING: Turn off all electrical service to the appliance when accessing the controls located inside the
control cabinet. The cabinet contains high voltage wiring and terminals. If the electrical service is not
turned off and these wires or terminals are touched, a dangerous shock causing personal injury or loss of
life could occur. Close the control cabinet before restoring electrical service to the appliance.
7. Check all electrical connections approximately one to two weeks after initial start-up to assure tightness.
Heating and cooling from operation can loosen connections. Visually inspect wire terminal points for any
discoloration on a monthly basis. Discoloration is likely due to a loose connection at the point nearest
discoloration. Check contactors periodically and clean if necessary and repair or replace pitted points caused by
foreign particles. Check fuses periodically for continuity and replace if necessary with the same type and rating.
8. Electric immersion INCOLOY® sheath elements are wound at high wattage ratings and must be completely
covered by water while in operation. Otherwise, they overheat and burn out. Scale from the water will collect on
the sheathing of the element over a period of time and must be removed periodically to extend the life of the
element. Water in some areas will produce the scale buildup more rapidly than other areas. The rapidity of the
scale buildup is also determined by the watt density of the element.
It is good maintenance practice to remove and clean 80 W/in² (18kW) density elements on a monthly basis. The
interval between removal and cleaning can usually be extended to six months when 40 W/in² (9kW) density
elements are installed. Most installations where 20 W/in² (4 1/2kW) density elements are used, require only
annual cleaning. Elements are cleaned by soaking in a scale dissolving solution. A 30” piece of four or six inch
PVC pipe with a cap on one end makes an ideal container for element cleaning. (See figure 6.) Contact a
chemical supply house for advice on the proper cleaning solution for your area.