Saudi Gazette RIYADH – The Civil Defense Directorate has urged citizens and expatriates to always check their electric wall-mounted water heaters and have them inspected by technicians every now and then. In a statement, the directorate said if the water temperature inside the heater rises to 90 degrees Celsius and calcium, lime and rust form inside, the safety valve will get clogged, which could lead to an explosion. The directorate called for setting the heater temperature to less than 60 degrees Celsius and unplugging the heater when not in use.