Model/datatypes/epc
Khalim Conn-Kowlessar bb9097e1a5 Slice S0380.53: Elmhurst §14.0 "Main Heating SAP Code" extraction + strict-raise
Cert 000565 surfaced an Elmhurst extractor schema gap. §14.0 lodges
"Main Heating SAP Code 224" identifying Main 1 as an Air Source Heat
Pump (SAP 10.2 Table 4a row 224: "Air source heat pump, 2013 or
later") — but the extractor was dropping the line. The mapper
therefore produced a `MainHeatingDetail` with `sap_main_heating_code
= None` AND `main_heating_index_number = None` (because `PCDF boiler
Reference = 0` for HP certs), leaving the cascade to fall back to
the 0.80 gas-boiler default efficiency.

Cascade impact on cert 000565 main_heating_fuel_kwh_per_yr pin:
- Before: actual 62,375.80 kWh/yr (= 59,008 / 0.80 wrong default)
  Δ +27,665.01 vs U985-0001-000565.pdf expected 34,710.79
- After:  actual 29,353.32 kWh/yr (= 59,008 / 1.70 HP COP via §A4.1)
  Δ −5,357.47 (remaining gap is on the space_heating side, not
  heating efficiency)

The strict-raise mirrors [[unmapped-api-code]] (Slice S0380.51) and
[[unmapped-elmhurst-label]] (cylinder size / glazing type) — when
neither the §14.0 SAP code nor the PCDB boiler reference identifies
Main 1, the mapper raises `UnmappedElmhurstLabel("main_heating",
...)` so the coverage gap surfaces at extraction time instead of as
an opaque downstream SAP delta. Per user end-of-S0380.52 directive:
"if we're missing mapping on EpcPropertyDataMapper - let's raise an
exception".

Spec source: SAP 10.2 §A4 Appendix A "Heat pump cascade", Table 4a
row 224 (Air source heat pump, 2013 or later) — `seasonal_efficiency`
reads the SAP code when no PCDB Table 105/362 record overrides.

Touched:
- datatypes/epc/surveys/elmhurst_site_notes.py: `MainHeating.
  main_heating_sap_code: Optional[int]` field added (treat 0 as None
  per Elmhurst convention — PCDB-listed boilers lodge §14.0 SAP code
  as 0 and identify themselves via the PCDB index instead)
- backend/documents_parser/elmhurst_extractor.py:
  `_extract_main_heating` reads §14.0 "Main Heating SAP Code" via the
  existing `_local_val` slice helper; 0/absent → None
- datatypes/epc/domain/mapper.py: `_map_elmhurst_sap_heating` passes
  `sap_main_heating_code=mh.main_heating_sap_code` to
  `MainHeatingDetail`, and raises `UnmappedElmhurstLabel` when
  neither identifier resolves

Cohort regression check: 415 pass + 10 expected 000565 failures
(unchanged from S0380.52 — same pins, different residuals). Pyright
net-zero on all 3 touched files.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-28 22:18:51 +00:00
..
domain Slice S0380.53: Elmhurst §14.0 "Main Heating SAP Code" extraction + strict-raise 2026-05-28 22:18:51 +00:00
loaders demo generated for use in address2uprn 2026-05-08 14:48:15 +00:00
schema Slice S0380.48: surface real-API pv_batteries[].battery_capacity (5 kWh) 2026-05-28 19:17:02 +00:00
search bolstering testing 2026-04-28 13:46:09 +00:00
surveys Slice S0380.53: Elmhurst §14.0 "Main Heating SAP Code" extraction + strict-raise 2026-05-28 22:18:51 +00:00
__init__.py testing out rebaselining 2026-02-12 22:25:03 +00:00
construction_age_band.py testing out rebaselining 2026-02-12 22:25:03 +00:00
efficiency.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
floor.py preparing partiy class 2026-02-05 08:54:27 +00:00
fuel.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
heating_controls.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
hotwater.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
main_heating.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
property_type_built_form.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
roof.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
walls.py beginning to assembly the parity class 2026-02-04 18:34:59 +00:00
windows.py testing out rebaselining 2026-02-12 22:25:03 +00:00