defects discovered during operation of the unit will be noted, and corrections made as soon as operation has ceased. Stop the operation immediately if a deficiency is  noted  that  could  damage  the  equipment.  After operation, the necessary PMCS must be performed. Report  defects  or  unsatisfactory  operating characteristics beyond your scope to your supervisor. Be certain the water heater drain cock is closed. Check to be sure the smoke-pipe elbow, the two lengths  of  the  smoke-pipe  guard  assembly,  and  the smoke pipe are securely installed. Start-up Procedures The  PMCS  procedures  are  contained  in  the operating  manual  provided  with  the  field  unit. Preparation for Use After having performed the recommended PMCS and the water heater is ready for use, you should proceed  as  follows: Before you start the bath unit, go to the “Operator’s Preventive  Maintenance  Checks  and  Services (PMCS)” and do the “Before Operation” checks and then proceed as follows: Make certain the water heater load limit switch is turned to OFF. Turn off the limit switch and connect the power cable to the power source. Close the fuel valve by turning it to the right. Remove the plug and fill the coupling with water. Replace  the  plug. Make sure the manual fuel valve is closed. Press the reset button to ensure the flame safeguard control is not locked out. Open the fuel valve and turn the load limit switch and power source ON. The fuel pressure gauge should indicate 100 psi. Open the blower shutter approximately halfway. View the ignition spark through the sight tube after the power is turned ON. Open the fuel pump primer plug and fill the fuel container with the fuel mixture. Replace the plug. Make sure that one end of the hose is connected to the supply fitting of the fuel filter and to the fittings on the vent. Connect the return fuel line to the drum fill adapter. NOTE The operator must periodically monitor the level of the fuel supply. The fuel container should be kept as full as possible to reduce wa- ter condensation. The frequency of refueling depends on the size of the fuel container. Ex- cessive water in the fuel supply decreases heater efficiency and corrodes both chamber and the burner. WARNING Exposed fuel and fuel vapor can ignite or explode,  resulting  in  possible  serious  injury and even death. Observe proper safety precau- tions when servicing the fuel system. Ensure the water heater is cold before servicing the burner. Check to see that all water lines are connected. Wait 7 seconds; then view the combustion through the sight tube. If combustion does not occur after an additional 12-second  wait,  the  buzzer  sounds  and  the  ignition spark shuts down. Wait 2 minutes after the buzzer sounds and press the safety reset button. If combustion still does not occur, troubleshoot the unit according to table  2-1. After  start-up,  the  exhaust  gases  from  the exhaust  stack  should  be  transparent  and  smokeless. When smoke is present, open the air band on the blower assembly slowly until the exhaust gases are transparent and smokeless. The water heater is now in automatic operation. Shutdown Procedures Perform the following shutdown procedures after normal use or when the equipment will not be used for an  extended  period: Turn off the fuel valve. Turn off the load limit switch. Turn off the water pump. If there is danger of the bath unit freezing, perform the  following  procedures: 2-5