The safest and most energy-efficient setting for a thermostat is between 120 degrees and 130 degrees Fahrenheit. A temperature setting less than 120 degrees could allow potentially fatal bacteria to propagate within the tank. A higher temperature setting can deliver scalding water. Some manufacturers suggest testing the valve every six months or so by raising and lowering the test lever on the valve. This should produce a sudden burst of hot water from the drain line connected to the valve.
More frequent testing can reduce the chance of a leak caused by mineral and corrosion buildup.
However, if a leak results immediately after a test, simply operate the test lever several times to free lodged debris that might be preventing the valve from seating properly. Toxic gases produced by the burner should be safely vented through a flue pipe that attaches to the top of the water heater. Frequent inspections should be made to ensure that the flue pipe is aligned with the water heater exhaust port. Be sure that the flue is drawing properly by holding a match under the vent pipe. If the flame is drawn toward the vent pipe, it is drawing properly.