Diaform Servicing and Adjustment Manual. Diaform Servicing and Adjustment Manual for Vertical Types A, B, AT, BT, 2A, 2B, 3A, 3B, 4A, R and 4B. Includes several useful sectional drawings. Manufacturers: Diaform Models: A B AT BT 2A 2B 3A 3B R Contents: Maintenance Manual