Cohort residual slice 18a: sap_heating lodgement on 000480 / 487 / 516

Wires PCDB main heating index + secondary heating type into the three
open fixtures. All three certs lodge:
- Vaillant ecoTEC PCDB index (000480=16839 pro 28, 000487=18119
  sustain 28, 000516=18118 sustain 24) at main_heating_data_source=1.
- Electricity Electric Panel/convector secondary (SAP code 691) at
  Table 11 fraction 0.10 (gas main + any secondary, page 188).
- number_baths (000480=0, 000487=1, 000516=1).

Confirmed against SAP 10.2 (14-03-2025) Table 11 page 188: "All gas,
liquid and solid fuel systems" main + "all secondary systems" →
fraction 0.10. PDF arithmetic on each fixture matches:
  000480: 12398.58 × 0.10 = 1239.86 kWh secondary ✓
  000487: 10834.78 × 0.10 = 1083.48 kWh secondary ✓
  000516: 12410.32 × 0.10 = 1241.03 kWh secondary ✓

Impact on continuous SAP delta (target <0.01):

  fixture | pre S18a | post S18a | status
  --------|----------|-----------|---------
  000480  |  +7.0885 |  +0.0012  | ✓ within 0.01
  000487  |  +5.5285 |  -1.9586  | over-corrected
  000516  |  +6.8375 |  +0.0349  | nearly closed (0.04)

000480 hits the 0.01 continuous gate — first time outside 000490.
000516 is within 0.04 (was +6.84). 000487 swung from +5.5 to -2.0,
suggesting the PCDB 18119 efficiency cascade diverges from what the
PDF assumes for that specific boiler — separate slice.

The previous fixture-lodgement gap was the dominant cost residual:
(242) secondary cost was £0 and (240) main heating was over-counting
because no PCDB efficiency was applied. Both close in this slice.
The remaining (251) standing charges (£120) gap is a calculator-side
issue addressed in the next slice (Table 12a page 191).

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

packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000480.py

@@ -28,7 +28,12 @@ from datatypes.epc.domain.epc_property_data import (
     SapVentilation,
     SapWindow,
 )
-from domain.ml.tests._fixtures import make_minimal_sap10_epc, make_window
+from domain.ml.tests._fixtures import (
+    make_main_heating_detail,
+    make_minimal_sap10_epc,
+    make_sap_heating,
+    make_window,
+)
 from domain.sap.worksheet.solar_gains import RoofWindowInput, RooflightInput
 from domain.sap.worksheet.ventilation import MechanicalVentilationKind
 from domain.sap.worksheet.water_heating import TABLE_J1_TCOLD_FROM_MAINS_C
@@ -154,6 +159,22 @@ def build_epc() -> EpcPropertyData:
             has_suspended_timber_floor=False,
             has_draught_lobby=False,
         ),
+        sap_heating=make_sap_heating(
+            # 000480 line 89: PCDF Index 16839 — Vaillant ecoTEC pro 28
+            # VUW GB 286/5-3 (88.70% winter, 87.00% summer eff). Same
+            # boiler as 000474.
+            main_heating_details=[
+                make_main_heating_detail(
+                    main_heating_index_number=16839,
+                    main_heating_data_source=1,
+                ),
+            ],
+            # 000480 line 115: "Electricity Electric Panel, convector or
+            # radiant heaters" → SAP code 691. Table 11 row "All gas...
+            # systems + all secondary systems" → fraction 0.10.
+            secondary_heating_type=691,
+            number_baths=0,  # 000480 line 124: Total number of baths = 0
+        ),
     )
 
 

packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000487.py

@@ -25,7 +25,12 @@ from datatypes.epc.domain.epc_property_data import (
     SapVentilation,
     SapWindow,
 )
-from domain.ml.tests._fixtures import make_minimal_sap10_epc, make_window
+from domain.ml.tests._fixtures import (
+    make_main_heating_detail,
+    make_minimal_sap10_epc,
+    make_sap_heating,
+    make_window,
+)
 from domain.sap.worksheet.solar_gains import RoofWindowInput, RooflightInput
 from domain.sap.worksheet.water_heating import TABLE_J1_TCOLD_FROM_MAINS_C
 
@@ -113,6 +118,20 @@ def build_epc() -> EpcPropertyData:
             suspended_timber_floor_sealed=False,
             has_draught_lobby=False,
         ),
+        sap_heating=make_sap_heating(
+            # 000487 line 88: PCDF Index 18119 — Vaillant ecoTEC sustain 28
+            # VUW 286/7-2 (H-GB).
+            main_heating_details=[
+                make_main_heating_detail(
+                    main_heating_index_number=18119,
+                    main_heating_data_source=1,
+                ),
+            ],
+            # 000487 line 114: "Electricity Electric Panel, convector or
+            # radiant heaters" → SAP code 691. Table 11 fraction 0.10.
+            secondary_heating_type=691,
+            number_baths=1,  # 000487 line 123: Total number of baths = 1
+        ),
     )
 
 

packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000516.py

@@ -32,7 +32,12 @@ from datatypes.epc.domain.epc_property_data import (
     SapVentilation,
     SapWindow,
 )
-from domain.ml.tests._fixtures import make_minimal_sap10_epc, make_window
+from domain.ml.tests._fixtures import (
+    make_main_heating_detail,
+    make_minimal_sap10_epc,
+    make_sap_heating,
+    make_window,
+)
 from domain.sap.worksheet.solar_gains import Orientation, RoofWindowInput, RooflightInput
 from domain.sap.worksheet.ventilation import MechanicalVentilationKind
 from domain.sap.worksheet.water_heating import TABLE_J1_TCOLD_FROM_MAINS_C
@@ -91,6 +96,20 @@ def build_epc() -> EpcPropertyData:
             has_suspended_timber_floor=False,
             has_draught_lobby=False,
         ),
+        sap_heating=make_sap_heating(
+            # 000516 line 82: PCDF Index 18118 — Vaillant ecoTEC sustain 24
+            # VUW 246/7-2 (H-GB). Same boiler as 000477.
+            main_heating_details=[
+                make_main_heating_detail(
+                    main_heating_index_number=18118,
+                    main_heating_data_source=1,
+                ),
+            ],
+            # 000516 line 108: "Electricity Electric Panel, convector or
+            # radiant heaters" → SAP code 691. Table 11 fraction 0.10.
+            secondary_heating_type=691,
+            number_baths=1,  # 000516 line 117: Total number of baths = 1
+        ),
     )