🔍 Key Concepts

• Trace the flow direction arrows around the fresh water thermostatic control valve (ports A, B, C) to see which side is the inlet and which are outlets. • Recall the difference between a 3‑way mixing valve (two inlets, one outlet) and a 3‑way diverting valve (one inlet, two outlets). • Determine whether the valve is trying to keep the engine outlet temperature or the engine inlet temperature constant by looking at where the temperature is being sensed and controlled.

💭 Think About

• From the engine, where does the hot jacket water go first, and how does it reach the thermostatic valve—before or after the keel cooler? • When the engine is cold, does the valve send most water through the keel cooler, or does it bypass the cooler back toward the engine, and what does that tell you about which temperature is being controlled? • Looking at ports A, B, and C, is the valve combining cooled and uncooled streams into one line, or splitting one stream into two possible paths?

✅ Before You Answer

• Verify which line physically returns to the engine inlet and which line comes from the engine outlet. • Confirm whether ports B and C both lead to different paths (keel cooler vs bypass), with only one common connection at A, indicating diverting vs mixing. • Check where the labeled fresh water temperature or temperature‑sensing point is located in relation to the valve: on the engine outlet side or engine inlet side.