the sales literature suggests average sizes that may be needed. Is one outlet (especially the shower) using more hot water than you think? Carefully review the family's hot water usage. Inexpensive flow control valves can be easily fitted to the shower outlets to reduce water usage. Ensure thermostat setting is appropriate. You may choose to adjust the thermostat upwards to gain additional hot water capacity. Check with your power supplier that the electricity supply hasn't had an interruption. Check that the fuse hasn't blown or trip switch needs resetting Check the cylinder isolation switch hasn't been knocked to the off position. A low pressure cylinder may have a safety vent pipe extended through the roof. Check that water is not flowing from the pipe. If water is flowing from this pipe, call your Rheem Service Centre or a registered plumber. This fault is also associated with a large increase on your power bill. A mains pressure cylinder has a pressure and temperature relief valve. If this valve fails water will pass through the cylinder and is discharged out of this pipe. If water is flowing from this pipe, call your Rheem Service Centre or a registered plumber. This fault is also associated with a large increase on your power bill. Only the Optima range of Rheem electric cylinders has a customer adjustable thermostat. The remainder of the range should only be adjusted by a qualified electrician, or licensed plumber. The range of the thermostat is 60C to 75C on domestic