Question 53 QMED04 - Boiler Technician-Watertender

The Correct Answer is A **Explanation for Option A (Correct):** When a compressed air reservoir (receiver tank) is placed immediately downstream of the compressor and is specifically used as an aftercooler, its primary function is to cool the hot, compressed air. Cooling the air causes the water vapor (humidity) in the air to condense into liquid water. This condensed water must be removed from the system to prevent corrosion, damage to downstream equipment, and system inefficiencies. Therefore, the reservoir **must be frequently drained of condensed water**. **Explanation for Incorrect Options:** * **B) It must be fitted with a moisture trap at the inlet.** * Moisture traps (or separators) are typically installed *after* the cooling process (downstream of the aftercooler) or are often integrated into the drain mechanism at the bottom of the reservoir itself. Placing a trap at the *inlet* (before significant cooling and condensation has occurred) would be ineffective for removing the bulk of the water vapor that condenses inside the reservoir. * **C) It must be fitted with a sight glass.** * While some large, specialized pressure vessels might utilize a sight glass to monitor fluid levels, a standard air receiver tank is not required to have one. The crucial requirement is draining the condensate, which is typically managed via an automatic or manual drain valve, not visual monitoring via a sight glass. * **D) It must be fitted with a manhole.** * Manholes are openings designed for human entry (inspection, cleaning, and maintenance) and are required primarily on very large pressure vessels (like boilers or very large storage tanks) where internal inspection is necessary. While air receivers need internal inspection, most standard-sized industrial receivers do not require a full manhole; they typically rely on inspection ports or removal from service for major internal checks. Fitting a manhole is not mandatory simply because the tank is used as an aftercooler.