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How to Bleed a Boiler

Bleeding a boiler sounds dramatic, but the task involves letting air out of the hot water lines. The air is either actual air that infiltrated the system or hydrogen gas from galvanic corrosion inside metal pipes. For a home with hot water heat, you may need to learn how to bleed a boiler. Older boilers typically need this done one or more times a year. You also have the option of contacting Oliver’s licensed technicians for boiler maintenance. We offer maintenance plans that will keep your boiler from failing before its time. If you don’t address gas in the lines, the heating system will perform poorly. Your home will develop cold spots while your utility bill rises.

Tools Necessary How to Bleed a Boiler

  • Radiator bleed-key or flathead screwdriver
  • Liquid collection tray or a bowl
  • An Old towel
  • Work gloves

When Does a Boiler Need Bleeding?

The air or gas trapped in pipes rises to the upper portions of a radiator. Because the hot water cannot enter the area filled with air, the radiator remains cool. A radiator that won’t heat up or is only warm at the bottom needs bleeding. You might also hear a bubbling noise in radiators compromised by air.

A modern boiler system is much less likely to develop this problem. Engineers have designed pressure tanks with rubber bladders that prevent the mixing of water and air. A licensed plumber could install an air eliminator on a boiler to stop air penetration. If your system is old, you could also explore heater replacement services from Oliver. A fully modern boiler installed by us works efficiently and produces consistent heat.

Directions for How to Bleed a Boiler

  1. Turn up the boiler to its highest setting.
  2. Leave the boiler running like this for a minimum of 15 minutes.
  3. Now shut off the boiler.
  4. Wait about another 15 minutes to let the system cool down.
  5. Go to the radiator on the ground floor that is farthest from the boiler.
  6. Wear gloves to protect your hands from hot water drippings or steam.
  7. Put a tray or bowl beneath the radiator valve.
  8. Fit a screwdriver or bleed key into the slot on the radiator valve.
  9. Turn the screw to the left.
  10. Air should start sputtering out as you turn the screw.
  11. Allow the valve to remain open until water drips out instead of air.
  12. Turn the screw to the right to shut it.
  13. Wipe up any water that may have splashed outside the tray.
  14. Take your tools to the next closest radiator to the boiler.
  15. Repeat the steps for opening the valves and releasing air until you’ve bled every radiator on the ground floor.
  16. If you have a second floor, go up there and bleed the radiators. Start with the one farthest from the boiler and work your way toward it.
  17. After finishing with all radiators, turn the heat back on.
  18. As the boiler gets going again, confirm that its pressure remains between 1.5 and 2 bars.

Experienced Care for Steam or Hot Water Boilers

Bleeding any radiator will be time-consuming. A technician from Oliver is available to perform this maintenance when you don’t have time. Additionally, if you bleed your boiler but problems persist, then you need boiler repair. We’re trained to fix all types of boilers found in homes throughout New Jersey and Pennsylvania. Whether your steam or hot water boiler runs on gas, propane, or oil, we’ll know how to fix it. Contact us for more information and heater repair today.

Need help with this project?

If you do not have the time, tools, or experience necessary to complete the project, please contact the professionals at Oliver for help.

Contact us today at 1-888-810-2681 Get a Free Estimate