The IRS says it will open its taxpayer assistance center in Bangor two days a week starting Wednesday. An IRS spokesman said late Tuesday the center will be open Wednesdays from 8:30 a.m. to 1 p.m. and 2 p.m. to 4:30 p.m., and Thursdays from 8:30 a.m. to noon. The center is located in the Margaret Chase Smith Federal Building on Harlow Street, and it operates on an appointment-only basis. Taxpayers can call 844-545-5640 to schedule appointments. The news of the center’s reopening came days after three members of Maine’s congressional delegation wrote to top IRS officials urging them to reopen the Bangor assistance center, which the IRS said it had closed temporarily. The IRS had said its closure of a taxpayer assistance center in Presque Isle last year was temporary, but that the agency has not reopened the Presque Isle center, according to a joint news release from Sens.