Boiler engineers can be expensive to call out, not to mention they are often hard to book during colder spells. If you have undertaken any repairs or maintenance of the system, go around and check the work to ensure there are no leaks. This boiler is bran new it's just got a few mark's on it nothing to bad its been in storage so picked up a few marks grab a bargain any more info plz call or text me on 07464047658.thanks. To find out more about the options available please. Ground source.