4
1-2. Main Components
A. Indicating Switch
B. Differential Pressure Unit (DPU)
• 289A and 291B are actuated by a Barton
®
Model 199 DPU
For detailed information on the actuating DPU, see the Barton
®
Model 199 DPU
user manual (Part No. 10030).
figure 1-2. Switches and adjustable controls