1991 Mueller Accu-Therm Plate Heat Exchanger. Model: AT40 F-20. S/N: 101036-2. Nat'l Bd: 18942. (96) 316 Stainless steel plates. Heating surface area: approx. 400 sq. ft. Plate pack max/min lengths: 16.89/16.32 in. MAWP: 100 psi @ 150 °F. MDMT: 32 °F @ 100 psi. Inlets: (1) 4 in. dia. port (hot), (1) 4 in. dia. port (cold). Outlets: (1) 4 in. dia. port (hot), (1) 4 in. dia. port (cold). The Accu-Therm is a compact heat exchanger consisting of embossed heat transfer plates with perimeter gaskets to contain pressure and control the flow of each medium. Accu-Therm plates ensure high thermal efficiency, uniform fluid distribution, minimal fouling, and suitability for full differential pressure rating. Single-pass arrangement over an F-Frame. Overall dimensions: 54 in. L x 21 in. W x 82 in. H.(ACN93).