Before starting, ensure the boiler and heating system are completely turned off and have cooled down to avoid burns or other injuries.

Steps:

• Locate the Sight Glass on the Boiler. It should look like the photo below.              
  

• If this tube has no water in it, your steam system will not work.

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• If there is very very little or no water in the system you have to add water.

• Add Water: Start slowly adding water. You should hear water flowing into the system. Make sure you do not overfill the tube. There may be a marking on the tube indicating the level of water that should be added.
  

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• The normal water level should be no more than 1/2 to 3/4 of the way to the top of the tube.
  

• Check the Pressure Gauge: Keep an eye on the boiler’s pressure gauge. Stop filling when it reaches the green zone, usually between 12-15 psi.
  

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• Warning:

                         Do not overfill the boiler. Doing so can cause dangerous pressure levels.