Khalim Conn-Kowlessar cbdee9ec3c S0380.238: single-point instantaneous water heaters incur no distribution loss ... Water heating SAP code 909 (electric instantaneous) and 907 (single-point gas) heat water at the point of use, serving one outlet with no distribution pipework. Per SAP 10.2 §4 (p.23, l.1416): "'Single-point' heaters, which are located at the point of use and serve only one outlet, do not have distribution losses either." So worksheet (46)m = 0 and the heat-required line collapses to SAP 10.2 worksheet l.7704 (62)m = 0.85 × (45)m + (46)m + (57)m + (59)m + (61)m = 0.85 × (45)m (all loss terms zero for a no-cylinder system). `distribution_loss_monthly_kwh` already supported the `is_instantaneous_at_point_of_use` flag (and its docstring already named codes 907/909), but `water_heating_from_cert` hard-coded it to False, so the cascade applied (46)m = 0.15 × (45)m to single-point heaters. That 0.15 distribution loss exactly cancelled the 0.85 reduction, leaving (62)m = (45)m. On the cat-10 room-heater fixture (ref 001431, code 909) that over-stated the water fuel (219) as 2082.6250 instead of the worksheet's 1770.2313, and inflated the (65)m heat gains (692.47 vs worksheet 442.55) which in turn suppressed space-heating demand. Thread the cert's existing instantaneous flag (`_INSTANTANEOUS_WATER_CODES` = {907, 909}) through `_water_heating_worksheet_and_gains` into both the demand-pass and final `water_heating_from_cert` calls. Pins (219) water fuel = 1770.2313 at abs 1e-4 via the extractor → mapper → rating cascade. §4 suite green (2414 passed, 1 skipped); no existing fixture exercised the 907/909 path. The residual space-heating fuel gap ((211) 11158.59 vs worksheet 11563.17) this exposes is a separate cause — next slice. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>		2026-06-05 19:00:02 +00:00
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fixtures	S0380.236: extension party-wall type read independently of "As Main Wall"	2026-06-05 09:19:43 +00:00
__init__.py	Map to RdSapSiteNotes from site notes JSON 🟥	2026-04-16 13:54:03 +00:00
test_elmhurst_end_to_end.py	Slice S0380.17: map Elmhurst §11 glazing-type labels to SAP10 codes	2026-05-27 23:05:52 +00:00
test_elmhurst_extractor.py	fix(extractor): drop windows-table header remnant from first window glazing type	2026-06-02 22:54:49 +00:00
test_end_to_end.py	P6.1 follow-on: unbox BuildingPartIdentifier at backend boundaries	2026-05-20 09:58:23 +00:00
test_extractor.py	Handle wall thickness "Unmeasurable" 🟩	2026-04-30 16:41:16 +00:00
test_heating_systems_corpus.py	S0380.185: record CH6 pin-forever proof — distribution-loss is a Summary-export gap	2026-06-02 19:21:28 +00:00
test_pdf.py	rename example site notes to PasHub_ and add Elmhurst example	2026-04-24 13:01:51 +00:00
test_room_heater_worksheet_001431.py	S0380.238: single-point instantaneous water heaters incur no distribution loss	2026-06-05 19:00:02 +00:00
test_summary_pdf_mapper_chain.py	S0380.237: map "Secondary glazing - Low emissivity" → SAP 10.2 code 12	2026-06-05 09:35:35 +00:00