Forty-five-year-old Adam Kilbride pretended he was registered under the nationwide Gas Safe scheme.
However he last legitimately worked under that scheme 13 years ago and has since received no up to date training.
Despite this his name was put forward by an estate agent and a letting agent in his home town of Burnley.
He demanded cash from his customers but gave out receipts printed with the official Gas Safe logo.
Kilbride of Grassington Road, Burnley, who runs a restaurant-bar in the town, pleaded guilty to an offence of masquerading as a registered Gas Safe engineer and two offences of doing work which contravened Health and Safety laws.