A system for testing fluid flow includes a first tube, a first flange disposed on an end of the first tube, a second tube, and a second flange disposed on an end of the second tube. The second flange is adjacent the first flange. A flow restricting sleeve surrounds the first flange and the second flange. The flow restricting sleeve has an inner surface and an outer surface, with a web extending from the inner surface and defining an orifice. The web extends between the first flange and the second flange. A coupler assembly surrounds the flow restricting sleeve.