🔍 Key Concepts

• Normally open (NO) vs normally closed (NC) contacts – look at whether the line actually touches the fixed contact or has a gap. • How a thermostat is drawn – it is a temperature‑actuated switch, so its symbol will usually be a basic switch contact with a distinctive temperature/thermal element added. • Match the device drawings (A–F) to the symbol set (1–14) – the thermostat’s mechanical picture should have a corresponding contact symbol below.

💭 Think About

• First, decide which device (A–F) is clearly a temperature‑sensing control with a bulb or capillary tube. Which one looks like a thermostat rather than a pressure or flow switch? • Once you’ve picked the thermostat device, scan the symbols 1–14 and find the pair that share the same special actuator marking (same little extra shape under the contact). One of that pair will be NO and the other NC. • Look closely at the contact in that pair: on which one is there a visible air gap between the movable arm and the fixed contact, indicating it is open in the normal condition?

✅ Before You Answer

• Confirm you are looking at a switch symbol with an added temperature element, not just a plain limit switch or flow switch. • Verify which contact symbol is open (gap) versus closed (touching) in its rest position. • Double‑check that the symbol you select has the same actuator style as the thermostat device’s other symbol (its NC counterpart) – there should be a matching pair, one NO and one NC.