What changed
Every change to PT Charts' pressure–temperature data, calculators and EPA 608 practice questions, newest first, with the date of each.
Updated
September 29, 2026
Redesigned every page. The chart pages now open on the tool: type or nudge a gauge pressure and read the saturation temperature on the refrigerant's own curve, with recent readings, a field mode for bright sun or dark attics, and a printable pocket card. Fixed two chart bugs: a temperature between two rows no longer blanks the pressure answer, and R-134a's vacuum can now be entered in inches of mercury. The superheat and subcooling calculator shows both answers side by side, the practice tests keep your picks through a reload and show a progress strip, and the guides open with an at-a-glance summary and a table of contents.
September 21, 2026
Added seven guides: chart routing, EPA 608 certification types and what each test covers, which leak-repair rule applies to a given appliance, what changed when R-454B and R-32 were added to EPA's SNAP safety-class listing, the R-22/HCFC phase-out, and a reclaim/cylinders checklist under the 2024 AIM Act rule.
September 19, 2026
Launched with PT charts for R-454B, R-32, R-410A, R-22 and R-134a, a superheat and subcooling calculator, and 25-question EPA 608 Core and Type II practice tests.