TM 9-2320-209-10-1 FRAME 7 1. Pull exhaust bypass fording valve control (1) out, turn it to side-to-side position. This will lock control and keep valve open. 2. When outside temperature goes above freezing (32 ° F), turn bypass fording valve control (1) to up and down position. Let it go back to close valve and stop heating. 3. Stop engine. (Refer to para 4-6e.) 4-201