{"id":198564,"date":"2025-03-10T06:59:41","date_gmt":"2025-03-10T06:59:41","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=198564"},"modified":"2025-03-10T06:59:44","modified_gmt":"2025-03-10T06:59:44","slug":"according-to-sae-standard-1990-motor-vehicle-a-c-r-12-recovery-equipment-must-be-capable-of-reducing-the-system-pressure-to","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/03\/10\/according-to-sae-standard-1990-motor-vehicle-a-c-r-12-recovery-equipment-must-be-capable-of-reducing-the-system-pressure-to\/","title":{"rendered":"According to SAE Standard 1990, Motor Vehicle A\/C R-12 recovery equipment must be capable of reducing the system pressure to"},"content":{"rendered":"\n

According to SAE Standard 1990, Motor Vehicle A\/C R-12 recovery equipment must be capable of reducing the system pressure to _<\/em><\/strong>.<\/p>\n\n\n\n

A) a pressure of 0 PSIG
B) a vacuum of 4 Inches of Mercury
C) a vacuum of 15 inches of Mercury
D) a vacuum of 27 inches of Mercury<\/p>\n\n\n\n

The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n

Correct Answer:<\/strong><\/h3>\n\n\n\n

D) A vacuum of 27 inches of Mercury<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation:<\/strong><\/h3>\n\n\n\n

The SAE (Society of Automotive Engineers) Standard J1990 (1990)<\/strong> specifies the requirements for refrigerant recovery and recycling equipment<\/strong> used in motor vehicle air conditioning (MVAC) systems<\/strong> that use R-12 refrigerant<\/strong> (also known as CFC-12<\/strong>). This standard was developed to ensure environmental safety by minimizing the release of ozone-depleting substances<\/strong> into the atmosphere.<\/p>\n\n\n\n

One of the key requirements outlined in SAE J1990<\/strong> is that the recovery equipment must be capable of reducing the system pressure to a vacuum level of at least 27 inches of Mercury (inHg)<\/strong>.<\/p>\n\n\n\n

Why 27 Inches of Mercury?<\/strong><\/h4>\n\n\n\n
    \n
  1. Effective Refrigerant Removal<\/strong>:<\/li>\n<\/ol>\n\n\n\n
      \n
    • R-12 refrigerant operates under high pressures. To ensure maximum refrigerant recovery<\/strong>, the system must be drawn into a deep vacuum. 27 inches of Mercury (inHg)<\/strong> is considered deep enough to extract most of the refrigerant and residual moisture from the system.<\/li>\n<\/ul>\n\n\n\n
        \n
      1. Prevent Refrigerant Emissions<\/strong>:<\/li>\n<\/ol>\n\n\n\n
          \n
        • If the system is not fully evacuated, some refrigerant may remain, leading to its release into the atmosphere. R-12 is a CFC (chlorofluorocarbon)<\/strong>, which contributes to ozone layer depletion<\/strong>.<\/li>\n<\/ul>\n\n\n\n
            \n
          1. Compliance with EPA Regulations<\/strong>:<\/li>\n<\/ol>\n\n\n\n
              \n
            • The Environmental Protection Agency (EPA)<\/strong> enforces refrigerant recovery laws under Section 609 of the Clean Air Act<\/strong>. Achieving a 27 inHg vacuum<\/strong> ensures compliance with federal regulations.<\/li>\n<\/ul>\n\n\n\n
                \n
              1. Proper System Maintenance<\/strong>:<\/li>\n<\/ol>\n\n\n\n
                  \n
                • Removing air and moisture from the A\/C system prevents corrosion<\/strong> and damage to internal components<\/strong>, improving the efficiency and lifespan of the air conditioning system.<\/li>\n<\/ul>\n\n\n\n

                  Thus, the correct answer is D) a vacuum of 27 inches of Mercury<\/strong>, as per SAE J1990 requirements.<\/p>\n\n\n\n

                  \n\n\n\n

                  Image Representation:<\/strong><\/h3>\n\n\n\n

                  A\/C refrigerant recovery machine achieving a vacuum of 27 inches of Mercury<\/strong> on its gauge.<\/p>\n\n\n\n

                  \"\"<\/figure>\n\n\n\n

                  I’ve generated an image of an automotive air conditioning refrigerant recovery machine showing a vacuum gauge reading 27 inches of Mercury (inHg)<\/strong> in a professional auto repair shop.<\/p>\n","protected":false},"excerpt":{"rendered":"

                  According to SAE Standard 1990, Motor Vehicle A\/C R-12 recovery equipment must be capable of reducing the system pressure to _. A) a pressure of 0 PSIGB) a vacuum of 4 Inches of MercuryC) a vacuum of 15 inches of MercuryD) a vacuum of 27 inches of Mercury The correct answer and explanation is : […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-198564","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/198564","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=198564"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/198564\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=198564"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=198564"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=198564"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}