| How many elements does the heater have?If it's two then you could have an element and/or a thermostat that has gone bad or isn't working properly.
Often,especially with a two element heater,when the water's temperature suddenly drops and stays at a constantly lower level it's because one of these has malfunctioned.
If this heater was working fine before and now isn't for no apparent reason I'm not sure adjustments will help you and suggest you look at these parts. |