A full inspection of your boiler should include:

1. Opening the Boiler casing

2. Checking for leaks or corrosion 

3. The electrics are tested as part of other safety checks

4. Gas Pressure is checked using a manometer

5. The Flue is checked for safe emissions using an analyser

6. Any parts that need cleaning will be checked and cleaned

7. If any parts need replacing, such as seals, they will be replaced (additional costs are incurred but these are minimal and should be agreed in advance)

8. The casing is replaced 

9. A service check list is given and the boiler log book signed if required for your warranty.