How to Install a Combi Boiler

Updated February 21, 2017

Combi boilers were the most common types of boilers installed in the 2000s. Tanks are not required and they heat water very quickly. They are also very easy to install, since they do not require very much plumbing expertise. Best of all, combi boilers are very efficient on energy, making them the greenest boilers available.

Determine the type of fuel in your area and choose a boiler based on this information.

Choose an area to install a boiler where the exhaust gasses can be released by the flue. Choose an area where the boiler can be serviced from all angles.

Cut a length of pipe that is long enough to reach the main pipeline and both the feed and returner on the combi boiler. Use the blowtorch and pipe bending spring if you need to create a corner out of two pipes.

If you use natural gas, use black threaded piping to connect your combi boiler to your main gas line.

If you use propane, connect the propane tank to the regulator on the combi boiler.

Turn on the water supply in order to fill the boiler with water.


Not all combi boilers are the same. If this guide does not help, consult the manual that came with the boiler. If you have lost the manual, pdf's for that manual are often found online.


Keep the boiler away from areas with a lot of moisture. Incorrectly using a boiler can lead to fires or explosions. Keep the boiler away from other appliances. Do not store flammables near the boiler. If you smell gas in your house, do not turn on any light switches or use any phones. Call the fire brigade immediately. Always hire a professional in order to adjust the cO2 output.

Things You'll Need

  • Copper piping with fitting
  • Black threaded piping
  • Tube cutter
  • Pipe bending spring
  • Blowtorch
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About the Author

Charles Pearson has written as a freelancer since 2009. He has a B.S. in literature from Purdue University Calumet and is currently working on his M.A. He has written the ebooks "Karate You Can Teach Your Kids," "Macadamia Growing Handout" and "The Raw Food Diet."