Economy 7 water heater?

with the POWER SUPPLY OFF.
look at your water tank check/test the heater element(s) have continuity,. you will probably have 2 heater elements, one for the top up/boost,located at the top of tank the other in the bottom is for the 7 hr off peak .
remove the single screw cover,now remove the leads from the heating element now test between the 2 ends of the heater with a meter/beeper if no beeper this is the faulty one.
water must drained from tank to change the element.

wirecutterman
February 2010