The heat limit registers on heat pumps using EMS_DEVICE_FLAG_HEATPUMP
(product 172/173) are bytes 2/3/4 of telegram 0x0492, read as a direct
index into enum_maxHeat. That table has only six entries, so any unit
whose auxiliary electric heater goes above 9 kW reports an index the
table cannot resolve.
Nothing bounds-checks the raw byte on the way in, and every render path
guards on `value < options_size`, so an out-of-range index is dropped
silently: no value is published to MQTT, the API omits the field, Home
Assistant shows `unknown`, and nothing appears in the log. Helpers::
value2enum stops at the same boundary, so the value cannot be written
back from EMS-ESP either, leaving the entity permanently stuck.
Measured on a Bosch Compress 7000i AW (CS7000iAW 13 OR-T, product 172)
with a 15 kW auxiliary heater, by setting each limit from the unit's own
display and reading telegram 0x0492 back:
display 12 / 9 / 6 kW -> 0x0492 data: 03 00 06 05 04
raw kW note
0 0 agrees with the existing table
1 2 not offered by this heater
2 3 not offered by this heater
3 4 not offered by this heater
4 6 agrees with the existing table
5 9 agrees with the existing table
6 12 new
7 15 new
Indices 0, 4 and 5 match what EMS-ESP already decodes, which confirms the
existing entries and their ordering; the table was correct, just short.
The 2 kW and 4 kW entries belong to the 4-stufig (2/4/6/9 kW) heater
variant described in the HPC 410 service manual section 4.2.2, so a
3 kW-stepped heater simply skips them and walks 0, 3, 6, 9, 12, 15 kW,
i.e. raw 0, 2, 4, 5, 6, 7. The same sparse pattern is already encoded for
CS6800 devices in Boiler::process_HpHeaterConfig, which maps raw
{0, 2, 4, 5} onto {0, 3, 6, 9} kW.
Only devices carrying EMS_DEVICE_FLAG_HEATPUMP are affected; CS6800
devices use enum_maxHeat1/enum_maxHeat2 and are unchanged. Verified with
the standalone build: `test entity_dump` differs from the committed
docs/dump_entities.csv in exactly the six maxheat rows of products 172
and 173, and nowhere else.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
proddy