water, steam, and electrical) vary with different types and kinds of boil ers. Always follow the manufacturer's instructions for the boiler being used. Before lining up a boiler, complete the following basic tasks: 1. Fuel oil a. Measure with a stick or gauge. b.   See that the proper valves are open. c. Remove any excess accumulation of water in the  tank. 2.  Gas a. Check the pressure. b. Check for leaks. 3.  Gas-fired  unit a.   Check and regulate the water level and line up the feed system. b.   Examine  the  burner,  control  valves,  and  safety shutouts for proper working condition before lighting  off. c.   Purge air out of the gas lines by external vents before lighting off. d.  Check  the  draft  devices  and  purge  the combustion chamber. e.   Light the pilot and set the flame. f. Open the main gas cock. g.  Close the burner controls switches to light the burner. h.  Maintain  the  fuel-air  ratio  for  complete combustion. 4.  Oil-fired  unit a. b. c. Check and regulate the water level. Line up the feedwater system. Check the operation of the feed  pump. Line up the fuel oil system. Purge the combustion chamber. d. Close the burner control switch; if automatic, the burner should light off. e.  Should  ignition  fail,  the  furnace  must  be purged before a second attempt is made. f. Do not allow oil to impinge on brickwork or part of the boiler. g. Maintain the proper air-fuel ratio. In  general,  the  basic  lighting  off  procedures  for most boilers are as follows: 1. Close the following valves: a. b. c. d. e. f. g. h. All blowdown valves and boiler drains. Chemical feed valves. Boiler  nonreturn. Main steam stops. Soot blower header (steam system) and all soot blowers. All burner fuel valves. Water column and feedwater regulator drains. Auxiliary valves, as necessary. 2. Open the following valves: a. b. C. d. e. f. g. h. 3 . 4 . 5. 6. 7. 8. 9. Vent valves on boiler drums and superheaters. Superheater drain valves. Recirculating line valves in economizer, if so fitted. Feedwater stop and check. Drum steam gauge connection. Water column gauge connections. Water column gauge glass valves. Auxiliary valves, as necessary. Start  filling  the  boiler  with  properly  treated water at a temperature close to the temperature of   the   pressure   parts.   The   temperature difference  should  not  be  greater  than  50°F  to avoid severe temperature stresses. Fill the boiler to level just below the middle of the glass on the water column. Close the induced draft fan dampers (or other flue gas control dampers). Start the induced draft fan. Close the forced draft fan dampers (or other air control  dampers). Start the forced draft fan. Start the air heater rotor, if a regenerative type of air heater is installed. Light  off  the  boiler  under  the  manufacturer’s instructions  and  maintain  a  firing  rate  so  the water temperature in the boiler is raised 100^oF per hour until operating pressure is reached. On 2-20