This is certainly to be sure the boiler is burning fuel as it was created for, this is completed employing a flue gas analyser and that is inserted in to the flue-pipe in addition to a studying is taken, If your readings are within the boilers suggestions then no further more action is required, but If your readings are out from the recommendations

What Is a Gas Safety Certificate as well as Why Is It Important?A Gas Safety Certificate is a legal paper that tape-records whether a gas device is secure to utilize. It is a file released by a signed up Gas Safe designer. It is normally one years of age, and also a new lessee is entitled to a duplicate of it within 28 days of moving in. A Gas Safe