{"id":23118,"date":"2026-09-26T11:49:30","date_gmt":"2026-09-26T11:49:30","guid":{"rendered":"https:\/\/www.examlabs.com\/certification\/?p=23118"},"modified":"2026-09-26T11:49:30","modified_gmt":"2026-09-26T11:49:30","slug":"nadca-ascs-practice-test-questions-and-exam-dumps-part20-q381-400","status":"publish","type":"post","link":"https:\/\/www.examlabs.com\/certification\/nadca-ascs-practice-test-questions-and-exam-dumps-part20-q381-400\/","title":{"rendered":"NADCA ASCS Practice Test Questions and Exam Dumps Part20 Q381-400"},"content":{"rendered":"

View Full <\/b>NADCA ASCS Exam Dumps<\/b><\/a> and Practice Test Dumps.<\/b><\/p>\n


\n<\/b>Question 381. What remains the preferred HVAC decontamination method when UV is installed<\/b><\/p>\n

    \n
  1. <\/b> Ozone treatment<\/span><\/li>\n
  2. <\/b> Source removal<\/span><\/li>\n
  3. <\/b> Air heating<\/span><\/li>\n
  4. <\/b> Humidity control<\/span><\/li>\n<\/ol>\n

    Correct Answer: 2. Source removal<\/b><\/p>\n

    Explanation:<\/b><\/p>\n

    Ultraviolet technology can support microbial control in appropriate HVAC applications, but NADCA continues to identify source removal as the primary method for cleaning and decontaminating HVAC systems. Source removal physically removes dust, debris, and other contamination from component surfaces instead of relying only on supplemental treatment technology. UV equipment can help control certain microorganisms when properly selected, installed, operated, and maintained, but it does not remove accumulated particulate material. Professional HVAC cleaning therefore continues to require inspection, suitable agitation, collection, containment, and cleanliness verification even when ultraviolet equipment is present.<\/span><\/p>\n

    Question 382. What should happen before servicing UVC lamps<\/b><\/p>\n

      \n
    1. <\/b> Increase lamp intensity<\/span><\/li>\n
    2. <\/b> Open all access doors<\/span><\/li>\n
    3. <\/b> Increase fan speed<\/span><\/li>\n
    4. <\/b> Power off and lock out the lamps<\/span><\/li>\n<\/ol>\n

      Correct Answer: 4. Power off and lock out the lamps<\/b><\/p>\n

      Explanation:<\/b><\/p>\n

      UVC lamps should be powered off and properly controlled through lockout procedures before technicians service equipment near them. Direct exposure to ultraviolet radiation can harm skin and eyes, so workers should not assume the lamp is safe merely because the HVAC fan is stopped. NADCA emphasizes that UVC exposure must be treated seriously and recommends lockout and tagout when lamps are being serviced. This follows the broader ASCS safety principle of controlling hazardous energy before maintenance or cleaning activities expose workers to equipment hazards.<\/span><\/p>\n

      Question 383. What hazardous substance can be present in a broken UVC lamp<\/b><\/p>\n

        \n
      1. <\/b> Mercury<\/span><\/li>\n
      2. <\/b> Refrigerant oil<\/span><\/li>\n
      3. <\/b> Asbestos<\/span><\/li>\n
      4. <\/b> Lead paint<\/span><\/li>\n<\/ol>\n

        Correct Answer: 1. Mercury<\/b><\/p>\n

        Explanation:<\/b><\/p>\n

        Many UVC lamps used in HVAC applications contain a small quantity of mercury. If one of these lamps breaks, technicians should recognize that the broken lamp can create a mercury exposure concern and should follow appropriate cleanup and safety procedures. NADCA specifically discusses mercury exposure as a hazard associated with UVC lamp breakage. This illustrates why ASCS professionals must understand equipment hazards in addition to ordinary dust removal. Cleaning personnel should avoid handling damaged specialized equipment casually when the component can release a hazardous material.<\/span><\/p>\n

        Question 384. Which UVC wavelength is commonly used to avoid ozone production<\/b><\/p>\n

          \n
        1. <\/b> 185 nanometers<\/span><\/li>\n
        2. <\/b> 100 nanometers<\/span><\/li>\n
        3. <\/b> 254 nanometers<\/span><\/li>\n
        4. <\/b> 400 nanometers<\/span><\/li>\n<\/ol>\n

          Correct Answer: 3. 254 nanometers<\/b><\/p>\n

          Explanation:<\/b><\/p>\n

          NADCA notes that ozone can be generated around a wavelength of 185 nanometers and recommends using UVC lamps operating at approximately 254 nanometers to avoid this ozone production concern. UVC equipment must still be properly installed and maintained to provide its intended benefit safely. An ASCS technician who encounters ultraviolet equipment should recognize that lamp type, wavelength, direct exposure, electrical energy, and mercury containing bulbs can all present considerations during inspection or cleaning. Source removal remains necessary even when UVC technology is installed.<\/span><\/p>\n

          Question 385. What characterizes a constant air volume system<\/b><\/p>\n

            \n
          1. <\/b> Relatively constant airflow<\/span><\/li>\n
          2. <\/b> No air movement<\/span><\/li>\n
          3. <\/b> Variable refrigerant only<\/span><\/li>\n
          4. <\/b> No supply fan<\/span><\/li>\n<\/ol>\n

            Correct Answer: 1. Relatively constant airflow<\/b><\/p>\n

            Explanation:<\/b><\/p>\n

            A constant air volume system generally supplies a relatively constant quantity of air while changing air temperature as necessary to meet space conditions. Understanding basic system types is important for ASCS technicians because cleaning methods and access planning depend on the mechanical configuration being serviced. The current ASCS exam specifically includes knowledge of HVAC system design and types of systems within the Mechanical Systems domain. Technicians should be able to distinguish common system arrangements and understand how air moves through them before beginning inspection or cleaning.<\/span><\/p>\n

            Question 386. What is the defining feature of a VAV system<\/b><\/p>\n

              \n
            1. <\/b> Constant water flow<\/span><\/li>\n
            2. <\/b> No zone control<\/span><\/li>\n
            3. <\/b> Fixed fan speed only<\/span><\/li>\n
            4. <\/b> Variable airflow to zones<\/span><\/li>\n<\/ol>\n

              Correct Answer: 4. Variable airflow to zones<\/b><\/p>\n

              Explanation:<\/b><\/p>\n

              A variable air volume system changes the quantity of air supplied to individual zones according to their conditioning requirements. VAV boxes commonly use internal dampers and controls and may also include reheat coils or fan powered components. The current ASCS Candidate Guide specifically recommends study of VAV boxes because technicians may encounter these devices while inspecting and cleaning commercial systems. Understanding how they function helps prevent damage to sensitive controls and ensures that internal air side components are considered within the cleaning scope.<\/span><\/p>\n

              Question 387. What is a basic feature of a split HVAC system<\/b><\/p>\n

                \n
              1. <\/b> All equipment is outdoors<\/span><\/li>\n
              2. <\/b> Major components are divided between indoor and outdoor sections<\/span><\/li>\n
              3. <\/b> It contains no coils<\/span><\/li>\n
              4. <\/b> It has no air distribution system<\/span><\/li>\n<\/ol>\n

                Correct Answer: 2. Major components are divided between indoor and outdoor sections<\/b><\/p>\n

                Explanation:<\/b><\/p>\n

                A split HVAC system separates major refrigeration and air conditioning components between indoor and outdoor equipment. A common arrangement places the evaporator coil and air handling components indoors while the compressor and condenser are located outdoors. ASCS candidates are expected to understand HVAC system design and different system types because cleaning professionals must recognize the equipment they encounter. Proper identification helps technicians distinguish air side surfaces that may require cleaning from components requiring mechanical service by another qualified HVAC professional.<\/span><\/p>\n

                Question 388. What is a basic characteristic of a packaged HVAC system<\/b><\/p>\n

                  \n
                1. <\/b> It has no fan<\/span><\/li>\n
                2. <\/b> It uses no coils<\/span><\/li>\n
                3. <\/b> Major components are contained in one unit<\/span><\/li>\n
                4. <\/b> It cannot serve ductwork<\/span><\/li>\n<\/ol>\n

                  Correct Answer: 3. Major components are contained in one unit<\/b><\/p>\n

                  Explanation:<\/b><\/p>\n

                  A packaged HVAC system places major heating or cooling components within one assembled unit rather than separating them between indoor and outdoor equipment. Depending on the design, packaged equipment can contain fans, coils, filters, heating components, drain pans, controls, and other air side surfaces. ASCS professionals should recognize different system configurations because cleaning access, contamination patterns, and component protection vary according to equipment design. The current exam outline specifically identifies knowledge of HVAC system design and system types as part of the Mechanical Systems domain.<\/span><\/p>\n

                  Question 389. What is the primary air side function of an evaporator coil<\/b><\/p>\n

                    \n
                  1. <\/b> Add dust to the air<\/span><\/li>\n
                  2. <\/b> Increase duct size<\/span><\/li>\n
                  3. <\/b> Store condensate<\/span><\/li>\n
                  4. <\/b> Absorb heat from the air<\/span><\/li>\n<\/ol>\n

                    Correct Answer: 4. Absorb heat from the air<\/b><\/p>\n

                    Explanation:<\/b><\/p>\n

                    An evaporator coil absorbs heat from the air passing across its surface during cooling operation. When the coil surface is cold enough, moisture from the air can also condense and collect in the drain pan. Contamination on the coil can interfere with airflow and heat transfer, making coil cleanliness an important ASCS topic. NADCA provides detailed procedures for inspecting and cleaning coils and requires methods that do not damage fins or other surfaces. Mechanical system understanding helps technicians recognize why coil condition matters to overall HVAC operation.<\/span><\/p>\n

                    Question 390. What is the main function of a condenser coil<\/b><\/p>\n

                      \n
                    1. <\/b> Reject heat from the refrigeration system<\/span><\/li>\n
                    2. <\/b> Collect return air<\/span><\/li>\n
                    3. <\/b> Filter supply air<\/span><\/li>\n
                    4. <\/b> Store wastewater<\/span><\/li>\n<\/ol>\n

                      Correct Answer: 1. Reject heat from the refrigeration system<\/b><\/p>\n

                      Explanation:<\/b><\/p>\n

                      The condenser coil releases heat carried by the refrigeration system to another medium, commonly outdoor air. This is different from the evaporator coil, which absorbs heat from the conditioned air stream. Basic understanding of heating and cooling coils is part of the Mechanical Systems knowledge expected of ASCS candidates. Although ASCS work focuses on HVAC hygiene rather than refrigeration repair, recognizing component purpose helps technicians distinguish cleaning responsibilities from mechanical service tasks and select methods that protect sensitive fins and surfaces.<\/span><\/p>\n

                      Question 391. What does sensible heat mainly change<\/b><\/p>\n

                        \n
                      1. <\/b> Air pressure only<\/span><\/li>\n
                      2. <\/b> Air temperature<\/span><\/li>\n
                      3. <\/b> Duct dimensions<\/span><\/li>\n
                      4. <\/b> Filter efficiency<\/span><\/li>\n<\/ol>\n

                        Correct Answer: 2. Air temperature<\/b><\/p>\n

                        Explanation:<\/b><\/p>\n

                        Sensible heat produces a measurable change in air temperature without requiring a moisture phase change. HVAC systems manage both temperature and moisture, so technicians benefit from understanding these basic mechanical concepts. Cooling coils can remove sensible heat while also removing latent heat when moisture condenses. Although ASCS professionals are not primarily responsible for designing refrigeration systems, the current exam requires knowledge of HVAC system design, system types, and components. Mechanical understanding supports better inspection and more informed cleaning decisions around coils and air handling equipment.<\/span><\/p>\n

                        Question 392. What is latent heat commonly associated with<\/b><\/p>\n

                          \n
                        1. <\/b> Fan rotation<\/span><\/li>\n
                        2. <\/b> Duct pressure only<\/span><\/li>\n
                        3. <\/b> Moisture phase change<\/span><\/li>\n
                        4. <\/b> Filter loading only<\/span><\/li>\n<\/ol>\n

                          Correct Answer: 3. Moisture phase change<\/b><\/p>\n

                          Explanation:<\/b><\/p>\n

                          Latent heat is associated with a change of state such as water vapor condensing into liquid water without the temperature change being the main effect. In HVAC systems, cooling coils often remove moisture from the air when their surfaces fall below the dew point. This moisture collects in the condensate pan and leaves through the drain system. Understanding moisture behavior is relevant to ASCS work because improper drainage or persistent wet conditions can contribute to contamination and material deterioration inside HVAC equipment.<\/span><\/p>\n

                          Question 393. What does static pressure represent in an HVAC air system<\/b><\/p>\n

                            \n
                          1. <\/b> Pressure acting within the duct system<\/span><\/li>\n
                          2. <\/b> Fan rotational speed<\/span><\/li>\n
                          3. <\/b> Air humidity<\/span><\/li>\n
                          4. <\/b> Coil temperature<\/span><\/li>\n<\/ol>\n

                            Correct Answer: 1. Pressure acting within the duct system<\/b><\/p>\n

                            Explanation:<\/b><\/p>\n

                            Static pressure represents pressure exerted within the HVAC air system and is commonly used to evaluate resistance to airflow across ducts, filters, coils, and other components. ASCS technicians may encounter static pressure measurements when evaluating coil cleaning effectiveness or negative pressure conditions. NADCA specifically recommends comparing pressure drop before and after coil cleaning because visual appearance alone can be misleading. Understanding basic pressure concepts helps technicians interpret common HVAC measurements without confusing pressure with velocity, humidity, or temperature.<\/span><\/p>\n

                            Question 394. What can an unusually high pressure drop across a dirty coil indicate<\/b><\/p>\n

                              \n
                            1. <\/b> Better drainage<\/span><\/li>\n
                            2. <\/b> Cleaner filters<\/span><\/li>\n
                            3. <\/b> Lower airflow resistance<\/span><\/li>\n
                            4. <\/b> Airflow restriction<\/span><\/li>\n<\/ol>\n

                              Correct Answer: 4. Airflow restriction<\/b><\/p>\n

                              Explanation:<\/b><\/p>\n

                              Heavy contamination between coil fins can increase resistance to airflow and contribute to a higher pressure drop across the coil. NADCA recommends obtaining pressure drop measurements before and after cleaning because visual inspection alone may not accurately demonstrate how much restriction exists. If cleaning removes significant contamination, the pressure relationship can provide useful evidence of improvement. Pressure measurements should be interpreted with system conditions in mind and do not replace direct cleanliness inspection, but they can support evaluation of coil cleaning effectiveness.<\/span><\/p>\n

                              Question 395. What must cleaning activities avoid doing to smoke and fire detection equipment<\/b><\/p>\n

                                \n
                              1. <\/b> Inspecting it visually<\/span><\/li>\n
                              2. <\/b> Impairing altering or damaging it<\/span><\/li>\n
                              3. <\/b> Documenting its location<\/span><\/li>\n
                              4. <\/b> Protecting it from debris<\/span><\/li>\n<\/ol>\n

                                Correct Answer: 2. Impairing altering or damaging it<\/b><\/p>\n

                                Explanation:<\/b><\/p>\n

                                NADCA requires HVAC cleaning activities to avoid impairing, altering, or damaging smoke and fire detection equipment located within the facility or connected to the HVAC system. These devices perform important life safety functions and must remain capable of operating as intended after cleaning. Technicians should identify relevant equipment during project planning and protect it from water, debris, tools, or accidental modification. If specialized service or testing is required, the appropriate qualified professional should be involved rather than allowing cleaning work to compromise the protection system.<\/span><\/p>\n

                                Question 396. What should normally happen to removable registers grilles and diffusers during cleaning<\/b><\/p>\n

                                  \n
                                1. <\/b> Leave them contaminated<\/span><\/li>\n
                                2. <\/b> Replace all of them<\/span><\/li>\n
                                3. <\/b> Remove clean and restore them<\/span><\/li>\n
                                4. <\/b> Seal them permanently<\/span><\/li>\n<\/ol>\n

                                  Correct Answer: 3. Remove clean and restore them<\/b><\/p>\n

                                  Explanation:<\/b><\/p>\n

                                  NADCA recommends that registers, grilles, diffusers, and other air distribution devices be removed when possible, properly cleaned, and then restored to their previous positions. These components form part of the air distribution pathway and can accumulate visible dust and debris. Cleaning them separately can provide better access to both the device and the duct opening. Care should be taken not to damage finishes, balancing settings, or mounting hardware. After cleaning, the devices should be returned correctly so normal airflow distribution can resume.<\/span><\/p>\n

                                  Question 397. What should operate continuously during Type 1 dry coil cleaning<\/b><\/p>\n

                                    \n
                                  1. <\/b> Humidifier<\/span><\/li>\n
                                  2. <\/b> Heating elements<\/span><\/li>\n
                                  3. <\/b> Supply fan<\/span><\/li>\n
                                  4. <\/b> Negative air machine<\/span><\/li>\n<\/ol>\n

                                    Correct Answer: 4. Negative air machine<\/b><\/p>\n

                                    Explanation:<\/b><\/p>\n

                                    During Type 1 dry coil cleaning, NADCA requires negative air machines to operate continuously. Dry cleaning can involve HEPA contact vacuuming, brushes, compressed air, and fin tools, all of which can disturb loose dust and debris. Continuous negative air helps capture this material and prevents it from migrating into the duct system or surrounding equipment. NADCA also requires the coil to be isolated from the duct system during the process. These controls allow dry cleaning to remove particulate contamination without simply redistributing it.<\/span><\/p>\n

                                    Question 398. Which coil condition requires Type 2 wet cleaning<\/b><\/p>\n

                                      \n
                                    1. <\/b> A newly installed thermostat<\/span><\/li>\n
                                    2. <\/b> Suspect microbial matter on the coil or drain pan<\/span><\/li>\n
                                    3. <\/b> A clean filter<\/span><\/li>\n
                                    4. <\/b> Normal fan operation<\/span><\/li>\n<\/ol>\n

                                      Correct Answer: 2. Suspect microbial matter on the coil or drain pan<\/b><\/p>\n

                                      Explanation:<\/b><\/p>\n

                                      NADCA specifies Type 2 wet cleaning when preliminary inspection reveals suspect microbial matter on any portion of the coil or drain pan. Type 2 cleaning is also appropriate when Type 1 dry cleaning cannot adequately remove adhered contamination. Wet methods can include compatible coil cleaning products, normal water washing, pressure washing, hot water, or steam cleaning. The technician must control water, protect equipment, follow product labeling, and avoid damaging coil surfaces or fins while achieving the required cleanliness.<\/span><\/p>\n

                                      Question 399. What should happen before Type 2 coil cleaning addresses adhered debris<\/b><\/p>\n

                                        \n
                                      1. <\/b> Remove nonadhered material with Type 1 methods<\/span><\/li>\n
                                      2. <\/b> Reenergize the system<\/span><\/li>\n
                                      3. <\/b> Apply a repair coating<\/span><\/li>\n
                                      4. <\/b> Increase refrigerant pressure<\/span><\/li>\n<\/ol>\n

                                        Correct Answer: 1. Remove nonadhered material with Type 1 methods<\/b><\/p>\n

                                        Explanation:<\/b><\/p>\n

                                        NADCA states that Type 2 wet coil cleaning should be performed after nonadhered substances have been removed using Type 1 dry cleaning methods. This sequence removes loose material before water or chemical cleaners are introduced to address more strongly adhered contamination. Type 2 methods can also include the techniques used in Type 1. Following the proper sequence helps improve cleaning effectiveness and keeps unnecessary debris from mixing with rinse water. Post cleaning inspection is then used to determine whether the coil requires additional cleaning or possible replacement.<\/span><\/p>\n

                                        Question 400. If a person passes the ASCS exam between March 1 and June 30 when does the certificate normally expire<\/b><\/p>\n

                                          \n
                                        1. <\/b> June 30 of the same year<\/span><\/li>\n
                                        2. <\/b> December 31 of the same year<\/span><\/li>\n
                                        3. <\/b> June 30 of the following renewal year<\/span><\/li>\n
                                        4. <\/b> Five years after the exam<\/span><\/li>\n<\/ol>\n

                                          Correct Answer: 3. June 30 of the following renewal year<\/b><\/p>\n

                                          Explanation:<\/b><\/p>\n

                                          NADCA currently states that an individual who passes the ASCS certification exam between March 1 and June 30 receives a certificate expiration date of June 30 of the following renewal year. Candidates who pass between July 1 and February 28 receive a June 30 expiration date within the upcoming renewal period. ASCS certification must then be renewed annually according to NADCA requirements. Certified professionals are responsible for tracking their expiration dates, earning the required continuing education credits, and completing renewal before the applicable deadline.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

                                          View Full NADCA ASCS Exam Dumps and Practice Test Dumps. Question 381. What remains the preferred HVAC decontamination method when UV is installed Ozone treatment Source removal Air heating Humidity control Correct Answer: 2. Source removal Explanation: Ultraviolet technology can support microbial control in appropriate HVAC applications, but NADCA continues to identify source removal as […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1648,1647],"tags":[],"_links":{"self":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/23118"}],"collection":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/comments?post=23118"}],"version-history":[{"count":1,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/23118\/revisions"}],"predecessor-version":[{"id":23119,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/posts\/23118\/revisions\/23119"}],"wp:attachment":[{"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/media?parent=23118"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/categories?post=23118"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.examlabs.com\/certification\/wp-json\/wp\/v2\/tags?post=23118"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}