Bimetallic Vacuum Switching Valve
- Drain coolant, and remove bimetallic vacuum switching valve (BVSV). BVSV is located on coolant outlet. Cool BVSV to less than 95°F (35° C). Blow air into upper BVSV vacuum port. Air should not flow through BVSV ports on ES250. On LS400, air should flow from upper BVSV vacuum port through BVSV air filter (located on top of BVSV).
- Heat BVSV in water to greater than 130°F (55°C). Blow air into upper BVSV vacuum port. On all models, air should flow from upper BVSV vacuum port through lower BVSV vacuum port.