SALEM – A Superior Court judge agreed to give a Lynn plumber, caught peddling heroin in 2008, a reprieve until after the holidays, but not without a stern warning.Timothy P. Kavanagh, 27, of 307 Parkland Ave., changed his plea of innocent to guilty to three counts of distribution of heroin with the intent to distribute before Judge Timothy Q. Feeley Monday afternoon in Salem Superior Court.As requested by defense lawyer Deborah B. McWade, the judge delayed sentencing Kavanagh until Jan. 4, but warned him that the agreed sentence proposed of two-and-a-half to three years in state prison could be revoked if he fails to appear.If he doesn’t, Kavanagh is facing up to 10 years on each of the three charges.Kavanagh remains free on $2,500 cash bail.Assistant District Attorney John B. Brennan said the three charges stem from three different drug sales to an undercover officer in Lynn in 2008.Authorities investigating a distribution enterprise received a telephone number for a person named “Jay,” later identified as Kavanagh, who was then living at 8 Chase St. in Lynn.On Aug. 12 arrangements were negotiated to purchase two twists of heroin. The undercover officer met with Kavanagh in the Franklin and Hanover streets area where $200 was handed to Kavanagh in exchange for two twists of heroin.Then on Sept. 22 the same arrangement was consummated where heroin was sold for $100 and again on Oct. 21. The last two transactions occurred in the Euclid Avenue area of Lynn.Police arrested Kavanagh following the last drug deal, seizing $490 in cash, believed to be proceeds from drug sales, along with a cell phone and a small quantity of marijuana.