Vaillant VR_71: Mc{1,2,3}Operation status receives value 4 (not in onoff enum) -> HA 'invalid option' #620

Summary

On a real VR_71 install the room controller writes status = 4 to Mc{1,2,3}Operation, but the field is typed onoff (0=off;1=on). ebusd therefore passes the raw 4 through and Home Assistant's enum sensor rejects every such update:

[homeassistant.components.mqtt.sensor] Ignoring invalid option received on topic
'ebusd/vr_71/Mc1Operation', got '4', allowed: off, on
[homeassistant.components.mqtt.sensor] Ignoring invalid option received on topic
'ebusd/vr_71/Mc2Operation', got '4', allowed: off, on

Definition

src/vaillant/26.vr_71.tsp:

model Mc1Operation {   // b523 0200 (Mc2 = 0201, Mc3 = 0202)
  status: onoff;       // -> compiled CSV: status,,UCH,0=off;1=on
  ...
}

Observed on the bus

• Device: MF=Vaillant;ID=VR_71;SW=0203;HW=5904 (slave 0x26)
• Source: the room controller (master 0x10) writes these telegrams.
• Over ~10 days of raw capture the master-side status byte was:
  • Mc1Operation: 0x00 ~91680×, 0x04 23×
  • Mc2Operation: 0x00 ~91743×, 0x04 19×
  • 0x04 occurs in short bursts roughly once per day around 10:00; 0x01 (on) was never observed — only 0 and 4.
• pump/mixer are slave-response fields and stay within range; only the master status field carries 4.

Question

What does status = 4 mean for a VR_71 mixer circuit? Given that 0x01 never appears and 0x04 does, 0=off;1=on looks incomplete/incorrect for this field. For reference, the Vaillant HMU pump/status field uses 0=off;1=on;2=overrun;4=hwc, so 4 here might indicate a hot-water/special mode — but that is unconfirmed for a mixer circuit.

Because status uses the shared onoff type, a proper fix probably means giving the Mc status its own enum (e.g. 0=off;1=on;…;4=<meaning>) rather than extending the global onoff.

Workaround

Locally I extended the field to 0=off;1=on;4=unknown so HA stops rejecting the value. Happy to relabel 4 once its meaning is known, and to capture more samples or correlate the timing of status=4 with circuit/DHW activity if that helps.