Boiler Boilout

Instructions for Boiler Boilout

After a new boiler is installed, a boiler boilout or cleaning is frequently recommended.

Follow this procedure to accomplish the boilout:

Day One

  1. Open  the manhole on top of boiler.  Sometimes it is positioned at the top of the back end of the boiler.
  2. Pump in the specified amount of chemical.   Sodium hydroxide (Caustic) and trisodium phosphate are normally recommended for boilout.
  3. Operate the boiler to a slight simmering (when it begins to boil), then turn off the boiler and keep it to near boiling for at least 8 hours.  Then shut off the boiler and allow it to cool.  These actions allow the chemical to react.
  4. Allow the boiler to set overnight.

Day Two

  1. If necessary, cool  the boiler by adding feedwater or makeup water slowly to boiler.  At the same time slowly drain the boiler off the bottom.  Note that before the boiler is fully drained, make sure that manufacturer instructions are followed as to not drain the boiler below the normal operating site glass level when temperatures are too hot.  Usually you can drain the boiler if water temperature is below 140 deg F. 
  2. After the boiler is drained, wash it out with a hose from top to bottom.  You can begin the washout process when the boiler level is down to half of the boiler volume.    As an alternative to thorough washing with a hose, sometimes it is easiest to drain the boiler, then fill and drain it a second or third time to get the boiler washed out sufficiently.  Wash out the boiler sufficiently to eliminate all color and debri from the effluent to the drain.

  3. The boilout is now complete

Then fill the boiler with water and chemical to get it ready for operation.  Add startup chemicals to the boiler as it is being filled (so that the chemical can mix thoroughly as water enters the boiler).  The amount of chemicals added is determined by the water treatment specialist/supplier contracted by the company.

The boiler can now be operated.  

  1. It is best to operate the boiler for at least an hour or more to drive off any residual oxygen dissolved in the boiler water.  If the boiler lies dormant for several days without actively eliminating oxygen from the system, oxygen may attack the boiler, resulting in corrosion.  
  2. Note-It is sometimes best to dump the condensate for 2-3 full days after a new boiler is put on line.