From 85455e86310417ee90ac77ca7d9468060d768413 Mon Sep 17 00:00:00 2001 From: Wesley Ray Date: Thu, 11 Jun 2026 23:26:29 -0400 Subject: [PATCH] canbus: add DSI-fault capture plan to open items Close propane valve, force a water-heater lockout, capture + diff against healthy baseline. Prime suspects: node 95 b1 (always FF) or node AE page-3 (always 00). Whichever flips becomes the DSI binary_sensor. Co-Authored-By: Claude Fable 5 --- canbus/README.md | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/canbus/README.md b/canbus/README.md index 842179b..b0011a1 100644 --- a/canbus/README.md +++ b/canbus/README.md @@ -134,6 +134,20 @@ uses to build its UI. `6A`/`7F`/`9C` (movement — slide?), find battery SoC / the "4 green lights" source. +### TODO: capture the DSI fault (planned 2026-06-12) + +The water-heater DSI fault is almost certainly on the bus but every capture so +far is of a *healthy* heater, so the fault encoding is unknown. **Plan:** close +the propane tank valve, run the water heater on gas until it locks out (DSI +fault light on panel), capture ~20 s with the CANable, then diff against a +healthy baseline. Prime suspects (both sit at a constant "all-clear" sentinel +in current captures): +- **node `95` (heater) page-3 `b1`** — always `0xFF`; expect it to drop/clear a bit on fault. +- **node `AE` (type 0x27, ?LP-gas/diagnostics) page-3** — always `0x00`; expect non-zero on fault. + +Whichever flips → becomes a `binary_sensor` in the ESPHome node (the DSI fault +the BLE app never exposed). Reset = reopen valve, re-light. + --- ## Hardware (BOM)