Before opening a low-pressure chiller to replace a failed tube bundle, the technician must:
a.Pressurize the shell to 20 psig
b.Add nitrogen and leave the refrigerant in place
c.Recover the charge to 25 mm Hg absolute
d.Vent the charge slowly to the roof
Explanation
The refrigerant must be recovered to 25 mm Hg absolute before the machine is opened for major service such as a tube-bundle replacement. Venting is illegal, and pressurizing above 10 psig risks the rupture disk. Only after proper recovery may the low-pressure shell be opened.
Law Reference: 40 CFR §82.156This topic, taught in full in the EPA Section 608 Certification guide. EPA 608 Universal Study Guide (2026) — Core + Type I/II/III, with the 2027 A2L update — PDF + EPUB, $14.99 · 14-day refund →
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