Combi Boiler Installation: Tips and Warnings to Make the Process Easy and Safe

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Combi boiler installation is not a very difficult task to cope with, but still there are many different rules and regulations you should get acquainted with. These regulations are very helpful in avoiding possible risks like physical injury or fire. Besides, they give tips on how to install units in some specific areas, handling electrical wires.

combi boiler installation

Always Read Instructions!

No matter what brand you give preference to, each of them provides the instruction manual. Read it carefully to know what should be done to cope with the task. Make sure you know what tools and materials should be used. List them before you start combi boiler installation. Count out the following items:

  • unit
  • necessary copper-piping
  • flue
  • new radiators

If you are sure you are well-acquainted with the instruction manual, get ready and start installing.

Your Basic Step-by-Step Guide

  • determine the fuel type you want to use or the one available in your area and choose a proper combination boiler, relying on this information;
  • choose a proper place for a combi boiler installation. It should be a place, where exhaust gases can be easily released by burning. This must be a place, where the heating unit can be addressed from different angles. The place should have enough space not only for the boiler unit, but also for a hot water storage cylinder, feed/expansion tanks, pumps and controls;
  • cut the length of the pipe that is long enough for reaching both the power and the main and returning to the boiler. Use a bent tube spring and a torch in order to create a corner of tubes;
  • if you are about to use natural gas, use a black threaded pipe in order to connect the combi boiler to the main gas line;
  • if you are about to use propane gas, make sure you’ve connected the propane tank regulator to the combi boiler;
  • open water to fill the combi boiler with it.

boiler installation

Perhaps, one of the hardest tasks is fitting the heating unit to the wall and setting up the required pipe work. The procedure takes much time, as one should be very careful and take special caution in making sure that everything is in its place, properly fitted and secured. Before starting the combi boiler installation process, make sure you switched off electrics and water.

If you use new radiators, do some air venting after everything is properly installed, bleed each of them, turning the key or valve. A small amount of water will spill over the top. Make sure you have a cloth to catch the overflow.


Keep in mind that all boilers aren’t the same. In case you see that our step-by-step guide doesn’t really help, you’d better consult a professional.

You should always keep your combination boiler away from places with much moist. If you use the boiler in an incorrect way, this leads to explosions and fires. Keeping it away from other appliances is also important, so never store any flammables near the unit. When you smell gas, don’t use phones or turn on the light.

Though combi boiler installation is not very difficult, you should hire a professional, when you’re not sure what should be done.