Merge PR #101: docs(frisko): the +20 min meter step is the compressor's second stage

docs/frisko/history-2026-10.md

@@ -52,17 +52,17 @@ Verified from history, 2026-10-24, 167 samples. Rule: compare the target with th
 
 The electric CWU heater is NOT physically connected (owner, 2026-10-25). Output 4115 = 100 and
 `zb_state` 2 only mean the controller's heater signal after 20 min of a CWU cycle; nothing is heated
-by it. Below, "heater" means that signal. The meter step at +20 min is real but its cause is
-unexplained; hypotheses: a compressor stage change (the controller does it at the same delay), another
-load on the same relay or phase, a circulation or pump switched with the signal. Do not read it as
-heater power. To test: log stage 4114 and the pumps' outputs around +20 min and compare the per-phase step.
+by it. Below, "heater" means that signal. The meter step at +20 min is the compressor's second stage
+(verified 2026-10-25): on 10-24 at 18:14:13 stage 4114 read 33, at 18:19:13 66; the meter rose at
+18:15 by ~940 W, split evenly over the phases (+330 / +300 / +310 W), a three-phase load, not a
+single-phase heater. The controller raises the stage and the heater signal together.
 
 Episodes in `heat_pump` (10-24); meter steps from `electricity.PRAD2` `total_power_active`.
 
 | Episode | On (sample window) | Off | Preceding CWU run | State at start |
 |---|---|---|---|---|
-| 1 | 11:43:48..11:48:48 | 12:04:56..12:09:56 (period end) | compressor since 11:24:55, ~20-24 min | stage 66, cwu 28 / target 43, outlet 39, outdoor 11 |
-| 2 | 18:14:13..18:19:13 (meter 18:15:13, +937 W) | ~18:20 (meter -3.7 kW) | compressor since 17:55:23, 19.8 min | stage 66, cwu 40.6 / 43, outlet 46 then 51.7 |
+| 1 | 11:43:48..11:48:48 | 12:04:56..12:09:56 (period end) | compressor since 11:24:55, ~20-24 min | stage 33 → 66, cwu 28 / target 43, outlet 39, outdoor 11 |
+| 2 | 18:14:13..18:19:13 (meter 18:15:13, +937 W) | ~18:20 (meter -3.7 kW) | compressor since 17:55:23, 19.8 min | stage 33 → 66, cwu 40.6 / 43, outlet 46 then 51.7 |
 
 Verified from history:
 - The heater joins 20.0 min (+-0.1) after the compressor starts a CWU cycle, if the cycle is still on.
@@ -78,8 +78,11 @@ Verified from history:
   outlet 51.7, compressor and heater off, outlet 42.1 five minutes later, cwu 42.2 below target).
   The compressor restarts ~18:25:30 (stage 33) without the heater (not 20 min) and stops at 18:30 when
   cwu reaches 43.0. Evening heater runs last 1-10 min (meter), ending at the outlet limit.
-- The 0.67-0.96 kW step lasts as long as the signal; it is small next to the compressor (+1.4-1.7 kW
-  at stage 33, about +3 kW with the pumps at 66).
+- The 0.67-0.96 kW step is stage 2 (66 %) over stage 1 (33 %). Over the house base (~1.0 kW on 10-24
+  evening) the pump draws +1.9..2.5 kW at stage 1 (rising as the outlet warms) and +3.4..3.7 kW at
+  stage 2. It lasts until the compressor stops.
+- At an outlet of 52 C (TmaxPc 4158) the controller stops the compressor because the outlet is too hot
+  (owner, 2026-10-25; seen 18:19-18:20 at 51.7 C); it restarts at stage 1 once the outlet has cooled.
 
 Hypothesis: the signal delay is measured from the compressor start of a CWU request, not from a
 temperature condition. A cycle that finishes within 20 min never raises it.

docs/frisko/rx910-se21.md

@@ -48,6 +48,7 @@ the Frisko app. Party mode (4140 = 2, hours in 4142) is a simpler "heat now" ove
   pressure-switch trips; three trips in one cycle latch a fault until manual reset (MR208-PC+ docs).
 - Frisko phone app: direct Modbus TCP, LAN only, 200–300 ms between requests, 5 s timeout.
 - History analysis of 2026-10 ([history-2026-10.md](history-2026-10.md)): the heater signal comes 20 min into a
-  CWU cycle (4147), `zb_state` 2 = that signal. The heater is not connected (owner, 2026-10-25); the meter
-  step at +20 min is unexplained; 4227 is unreliable for "heating CWU"; the controller clock
+  CWU cycle (4147), `zb_state` 2 = that signal. The heater is not connected (owner, 2026-10-25); at the
+  same moment the compressor goes from stage 1 to 2 (the +0.9 kW meter step, three-phase); at an outlet
+  of 52 °C (TmaxPc) it stops; 4227 is unreliable for "heating CWU"; the controller clock
   does not follow DST; period = target compared with the setpoints, valid only with 4226 = 1.