Question 32 DDE04 - Designated Duty Engineer - 1000-4000 HP

The Correct Answer is B **Why Option B ("80°C") is correct:** The original thermostat begins opening at $180^{\circ}\text{F}$. To find the closest Celsius replacement, we must convert $180^{\circ}\text{F}$ to Celsius using the conversion formula: $$\text{C} = (\text{F} - 32) \times \frac{5}{9}$$ Substituting the value: $$\text{C} = (180 - 32) \times \frac{5}{9}$$ $$\text{C} = 148 \times \frac{5}{9}$$ $$\text{C} = \frac{740}{9}$$ $$\text{C} \approx 82.22^{\circ}\text{C}$$ Comparing this calculated value ($82.22^{\circ}\text{C}$) to the available options, $80^{\circ}\text{C}$ is the closest standard thermostat setting. **Why the other options are incorrect:** * **A) $70^{\circ}\text{C}$:** This temperature is equivalent to approximately $158^{\circ}\text{F}$. This is $22^{\circ}\text{F}$ lower than the required $180^{\circ}\text{F}$ setting and is significantly less accurate than the $80^{\circ}\text{C}$ option. * **C) $90^{\circ}\text{C}$:** This temperature is equivalent to approximately $194^{\circ}\text{F}$. This is $14^{\circ}\text{F}$ higher than the required $180^{\circ}\text{F}$ setting. Since $80^{\circ}\text{C}$ ($176^{\circ}\text{F}$) is only $4^{\circ}\text{F}$ below the target, $90^{\circ}\text{C}$ is much further away than $80^{\circ}\text{C}$. * **D) $100^{\circ}\text{C}$:** This temperature is equivalent to $212^{\circ}\text{F}$ (the boiling point of water at standard atmospheric pressure). This is $32^{\circ}\text{F}$ higher than the required setting, which is far too high for a proper replacement.