Slice S0380.101: HP SAP code 211-227/521-527 → main_heating_category=4 (SAP 10.2 Table 4a)

SAP 10.2 Table 4a (PDF p.165) lists "Heat pumps" as category 4 for
SAP main-heating codes:

    211-217 — ground/water source heat pumps
    221-227 — air source heat pumps (224 = ASHP 2013+, COP 1.70)
    521-527 — warm-air heat pumps

Cert 000565 Main 1 lodges `Main Heating SAP Code = 224` (ASHP 2013+)
with `PCDF boiler Reference = 0` — i.e. no PCDB Table 362 lookup is
possible. Pre-slice `_elmhurst_main_heating_category` returned None
on this path (the existing PCDB-Table-362-membership check failed),
falling through to the cascade's `_DEFAULT_PUMPS_FANS_KWH_PER_YR =
130` (incorrect — HP circulation pump's electricity is inside the
system COP per SAP 10.2 Table 4f line "Heat pumps", so the cascade
row is 0 kWh/year for category 4).

Single-line fix: after the existing PCDB-resolution branches, check
`mh.main_heating_sap_code in _HEAT_PUMP_SAP_MAIN_HEATING_CODES` and
return category 4 if so. New frozenset of HP codes (subset of the
existing `_ELECTRIC_SAP_MAIN_HEATING_CODES`).

Transient state at HEAD (cert 000565):
- main_heating_category: None → 4 ✓
- pumps_fans cascade: 255.0 → 125.0 kWh/yr (HP base 0 + flue 45 +
  solar HW 80; MEV +127.5 kWh still missing — wiring lands in
  S0380.102)
- sap_score (int): 29 ✓ EXACT preserved
- sap_score_continuous: 28.31 → 28.69 (transient drift +0.39 vs ws;
  the previously-cancelling +130 over-count is gone, restoring the
  MEV-under net negative — closes when S0380.102 lands)

Cohort safety: cohort certs 000474..000516 are gas-combi with
`sap_main_heating_code=None` (PCDB Table 105 boiler identified via
the index instead). No cohort cert affected. Cert 0380 + other
golden HP fixtures lodge category=4 via the API mapper, also
unaffected.

Per the spec citation in [[feedback-spec-citation-in-commits]] +
the standing TODO at mapper.py:4037-4043, this slice is the
category half of the coupled cert 000565 closure arc.

Pyright net-zero per touched file.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/documents_parser/tests/test_summary_pdf_mapper_chain.py

@@ -1847,6 +1847,33 @@ def test_summary_000565_ext2_floor_routes_to_u_value_0p22_via_table_20_per_rdsap
     assert bp_2.floor_insulation_thickness == "200mm"
 
 
+def test_summary_000565_main_1_ashp_sap_code_224_routes_to_main_heating_category_4_per_sap_table_4a() -> None:
+    # Arrange — SAP 10.2 Table 4a (PDF p.165) "Main heating systems":
+    # the category column lists "Heat pumps" as category 4. Codes in
+    # rows 211-217 (ground/water source HP) and 221-227 (air source HP)
+    # and 521-527 (warm-air HP) all map to category 4.
+    #
+    # Cert 000565 Main 1 lodges `Main Heating SAP Code = 224` (Air
+    # source heat pump, 2013 or later — SAP 10.2 Appendix N efficiency
+    # row 224, COP 1.70). Without a PCDB Table 362 record (cert lodges
+    # `PCDF boiler Reference = 0`) the existing mapper's `_elmhurst_
+    # main_heating_category` returns None, which falls through to the
+    # cascade's `_DEFAULT_PUMPS_FANS_KWH_PER_YR = 130` (incorrect — HP
+    # circulation pump's electricity is inside the system COP per
+    # SAP 10.2 Table 4f, so the category 4 row is 0 kWh/year).
+    pages = _summary_pdf_to_textract_style_pages(_SUMMARY_000565_PDF)
+    site_notes = ElmhurstSiteNotesExtractor(pages).extract()
+
+    # Act
+    epc = EpcPropertyDataMapper.from_elmhurst_site_notes(site_notes)
+
+    # Assert
+    assert epc.sap_heating is not None
+    main_1 = epc.sap_heating.main_heating_details[0]
+    assert main_1.sap_main_heating_code == 224
+    assert main_1.main_heating_category == 4
+
+
 def test_summary_000565_ext1_floor_above_partially_heated_routes_to_u_value_0p7_per_rdsap_10_section_5_14() -> None:
     # Arrange — RdSAP 10 §5.14 (PDF p.47) "U-value of floor above a
     # partially heated space":

datatypes/epc/domain/mapper.py

@@ -3853,6 +3853,22 @@ _ELECTRIC_SAP_MAIN_HEATING_CODES: Final[frozenset[int]] = frozenset(
     + list(range(521, 528))
 )
 
+# SAP 10.2 Table 4a "Heat pumps" rows — codes whose `main_heating_
+# category` is 4 per the table's category column. Used when the cert
+# lodges a Table 4a SAP code but no PCDB Table 362 record (the
+# preferred identifier per `_elmhurst_main_heating_category`). Subset
+# of `_ELECTRIC_SAP_MAIN_HEATING_CODES`.
+#
+#   211-217 — ground/water source heat pumps
+#   221-227 — air source heat pumps (224 = ASHP 2013+, the cert 000565
+#             Main 1 lodging)
+#   521-527 — warm-air heat pumps
+_HEAT_PUMP_SAP_MAIN_HEATING_CODES: Final[frozenset[int]] = frozenset(
+    list(range(211, 218))
+    + list(range(221, 228))
+    + list(range(521, 528))
+)
+
 
 class UnmappedElmhurstLabel(ValueError):
     """An Elmhurst Summary lodged a finite-enum label that the mapper
@@ -4030,22 +4046,22 @@ def _elmhurst_main_heating_category(
     lodged data. A PCDB index that resolves to a Table 362 record is a
     heat pump (category 4) — Table 362 lists heat pumps only, so
     membership is the authoritative signal. A PCDB-referenced boiler on
-    mains/LPG gas is category 2 (gas-fired boilers). Other system types
-    fall through to None so the cascade applies its default pumps_fans
-    130 kWh/yr until extended.
+    mains/LPG gas is category 2 (gas-fired boilers).
 
-    TODO: route Table 4a HP SAP codes (211-227, 521-527) to
-    category=4 when no PCDB Table 362 record is lodged. Currently
-    deferred because the correct dispatch needs (a) Table 12a
-    high/low rate split for HP-on-E7 cost cascade and (b) Table 4f
-    MEV / flue-fan / solar HW pump components for pumps_fans —
-    without both, naive category=4 dispatch overshoots cost by
-    £1.3k and undershoots pumps_fans by 252 kWh on cert 000565.
+    SAP 10.2 Table 4a (PDF p.165) lists "Heat pumps" as category 4 for
+    SAP codes 211-217 (ground/water source), 221-227 (air source) and
+    521-527 (warm-air). When a cert lodges one of these codes WITHOUT
+    a PCDB Table 362 record (e.g. cert 000565 Main 1: SAP code 224
+    + `PCDF boiler Reference = 0`), category 4 still applies — the
+    cascade's pumps_fans path then routes through the HP-specific 0
+    kWh/yr row (Table 4f) rather than the 130 kWh/yr default base.
     """
     if pcdb_index is not None and heat_pump_record(pcdb_index) is not None:
         return _ELMHURST_HEATING_CATEGORY_HEAT_PUMP
     if pcdb_index is not None and mh.fuel_type in _ELMHURST_GAS_BOILER_FUEL_TYPES:
         return _ELMHURST_HEATING_CATEGORY_GAS_BOILER
+    if mh.main_heating_sap_code in _HEAT_PUMP_SAP_MAIN_HEATING_CODES:
+        return _ELMHURST_HEATING_CATEGORY_HEAT_PUMP
     return None