A free diagnostic reference for working techs: fault codes, PT charts, and OEM specs — where every verified value is pinned to a named service document, its page, and a cryptographic hash of the exact edition.
Open ToolboxHVAC How verification worksGoodman / Amana / Daikin · 92/96% single-stage gas furnaces · 7-segment display
Built for the attic, the crawlspace, and the parking lot before the callback. Each tool tells you what grade of information it's giving you — verified OEM data, located references, or field teaching — and never dresses one up as another.
Exact-match search across the verified corpus, starting with the Goodman/Amana/Daikin 9S single-stage furnace family — full 7-segment troubleshooting table, lockouts, and A2L mitigation codes.
VERIFIED · SOURCE-PINNEDWhen the app knows the equipment family, the OEM's printed number outranks the generic band — igniter resistance, flame current — with the document and page on screen.
VERIFIED · IN CONTEXTR-410A, R-454B, R-32, R-22, R-407C, R-134a. Out-of-range inputs refuse instead of extrapolating.
REFERENCE-GRADE · FROZENTarget calculators that go neutral when the method doesn't apply — a fixed-orifice target below usable range says "use the OEM procedure," not a color.
GOVERNED THRESHOLDSA pass/fail verdict only against the tolerance printed on the can in front of you. ±6% is an assumption, not the spec — the app says so.
SELF-SOURCED VERDICTStep-by-step triage where every diagnostic number is registered and traceable — nothing hides in the prose.
GOVERNED · TEACHING"Verified" on this site is a machine-checked state, re-proven on every release build. Here is the whole chain for the card above:
Daikin's Service and Troubleshooting, RS6612301, printed 2024-05 — registered with its publisher, edition, and page count.
The exact PDF edition is fingerprinted: sha256 9227da83097f… A different revision, a re-export, a wrong file — the fingerprint breaks.
Each record cites its pages and section. The build recomputes the whole chain; a wrong printed date or an out-of-range page refuses to ship.
The card shows the value and its receipt. If we can't prove it, it renders as reference teaching — never as a verdict.
The machine layer is complete and re-proven on every build. The human layer — independent licensed-trade review and legal review — is tracked on a public status page that is generated from the same ledger that gates the release: it cannot say "approved" before it happens. Spot an error? Send the controlling document, edition, and page; confirmed corrections are minted through the same pinned pipeline as everything else.
No account, no ads, no tracking — install it once and it works in the basement with no bars.
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