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    EPA 608 Type III · free practice

    EPA 608 Type III Practice Questions — Low-Pressure Chillers

    Type III covers low-pressure equipment — chillers using refrigerants like R-123 or R-11 (centrifugal water chillers in large commercial buildings). These free practice questions cover the unique recovery and evacuation requirements for low-pressure systems, the rupture-disk and pressure-relief considerations, and the leak-rate thresholds that determine when a low-pressure chiller's refrigerant must be repaired or retired.

    Practice Type III questions free

    Sample questions

    1. A Type III (low-pressure) appliance is defined as one with refrigerant:

    1. A. Boiling above 50 °C at atmospheric pressure
    2. B. Boiling between 10 °C and 50 °C at atmospheric pressure
    3. C. Boiling below 10 °C at atmospheric pressure
    4. D. Operating only with hydrocarbons
    Show explanation

    Low-pressure refrigerants (R-11, R-123, R-1233zd) boil ABOVE 50 °C (122 °F) at atmospheric pressure. Their evaporators operate below atmospheric pressure during normal operation — air leaks IN rather than refrigerant leaking out.

    Ref: 40 CFR §82.152

    2. During recovery from a low-pressure chiller, equipment manufactured after Nov 1993 must achieve:

    1. A. 0 mm Hg absolute
    2. B. 15 in Hg vacuum
    3. C. 25 mm Hg absolute
    4. D. 29 in Hg vacuum
    Show explanation

    EPA Table 1: low-pressure appliances require recovery to 25 mm Hg absolute pressure with post-1993 equipment. Older equipment was allowed to recover only to 25 in Hg vacuum (about 127 mm Hg absolute).

    Ref: 40 CFR §82.158

    3. A purge unit on a low-pressure chiller is used to:

    1. A. Add refrigerant during a service call
    2. B. Remove non-condensable gases (mostly air and moisture) that leak in during operation
    3. C. Pressurize the evaporator for leak detection
    4. D. Test the compressor motor windings
    Show explanation

    Purge units recover the small amount of refrigerant that escapes with air during operation, separate it, and return refrigerant to the chiller while venting non-condensables. Modern high-efficiency purge units lose ~0.05 lb refrigerant per pound of non-condensables purged.

    Practice Type III questions free

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    Frequently asked

    What refrigerants are considered low-pressure?

    Refrigerants whose vapor pressure is below 45 psia at 104°F — R-123, R-11 (legacy), R-113 (legacy). Almost exclusively used in large centrifugal chillers.

    What recovery vacuum does Type III require?

    Equipment manufactured after 11/15/93 must reach 25 mm Hg vacuum for low-pressure recovery. Pre-1993 equipment has different thresholds documented in the answer key.