Petitioner cooperative corporation's motion for summary judgment of possession should have been granted. The evidentiary proof submitted by petitioner established, prima facie, that respondents breached paragraph 21 of the governing proprietary lease agreement, which required proprietary lessees to obtain the Cooperative Board's "written consent" before installing any "air conditioning system." Petitioner's proof established that respondents submitted a written application for approval of certain alteration work within their apartment; the application affirmatively stated that "NO WORK REGARDING BUILDING ENVELOPE, HVAC" would be performed; and that respondents subsequently installed a central air conditioning ("HVAC") system on the facade of the building without first obtaining petitioner's written consent (see Rutherford Tenants Corp. v Kaufman, 212 AD2d 416 [1995]; Levin v 40 Fifth Ave. Corp., 24 AD3d 244 [2005]).