How to Test Boiler Combustion Efficiency

What You'll Need
Combustion meter

The efficiency of the boiler in your home can be measured by checking the boiler combustion efficiency. This is often one of the first things that are checked by a gas electrician when they are maintaining your boiler, and also when they are looking for problems such as leaks or damage. Combustion efficiency should be between 75 and 90%, but this efficiency can fall to less than 50% if you do not properly maintain it. Checking your boiler combustion efficiency will help you to ensure that you are getting the best out of your boiler, and also help alert you to potential problems and deficiencies. Getting this job done doesn’t need the assistance of a professional if you have some basic home improvement skills. All you have to do is follow a few simple guidelines to get the job done quickly and easily.

Step 1 – Start the Boiler

You will need to have completely removed any hot water from the system, and have left it sitting idle overnight. You should take a gas (or electricity) meter reading, so you know exactly how much electricity has been used up to that point. Turn off all other electrical items, so that the only thing being used is the boiler. Start up the boiler, and note how long it takes for the boiler to heat enough water to fill a kettle. This should tell you how efficient your boiler is, provided you can do some basic maths.

Step 2 – Do Some Sums

Work out the amount of heat expressed. The equation is: Heat = Flow of Water (mass divided by time), times the specific Heat Capacity of the boiler, and the Temperature Difference of the boiler (H=m/t+hcap+Temp diff). Do this calculation based upon the findings that you have obtained from the first step. You should now have a clear idea of how combustion efficient your boiler is

Step 3 – Check for Problems

Once that is completed, you may want to check to see whether there are any problems with your boiler which is reducing the amount of boiler efficiency. This can be anything from increased limescale in the tank preventing water from being heated as efficiently as possible, to slow pumping of water due to a problem with the circulator pump. Check all of the systems that operate off of the boiler, and turn off any that are giving you problems. Use your screwdriver to undo any devices which look faulty.

Step 4 – Finishing

Before you finish the project you may wish to check the capacity reckoning with a special meter designed to calculate your boiler efficiency. These meters are not usually available to the public, so you should probably check with a professional before using one, but if you can find a meter such as this, you will be able to check your working out.