Hi
As Dave said thermocouple or grease, more likely thermocouple.
Dont be fobbed off as in another post; customer reported engineer tweaking bypass on gas tap, make sure they change FSD for new type (twin lead, one to tap one to earth)
Anonymous wrote:…meant to ask what doe sthe thermocouple look like!
Hi
Its situated next to ignitor and is slim and bullet shaped.
Please take Dave’s advice and get a corgi registered installer; check repairs@ for your nearest engineer.