Model/tests/infrastructure/epc_client
Khalim Conn-Kowlessar 9694650abe fix(water-heating): derive combi keep-hot from the PCDB record, default no-keep-hot
SAP 10.2 Table 3a (PDF p.160) additional combi loss (61)m. Two coupled
defects, both surfaced by simulated case 49 (000565 + gas combi, U985
"Combi keep hot type = None") sitting at SAP 71.43 vs the worksheet's 72:

1. The cascade defaulted EVERY non-PCDB combi to the flat keep-hot
   time-clock row (600 × n/365). A combi WITHOUT a keep-hot facility uses
   row 1 (600 × fu × n/365, fu = V_d/100 when daily HW < 100 L/day) —
   over-counting (61)m for the no-keep-hot cohort. `water_heating_from_
   cert` now defaults to the "without keep-hot" row.

2. `pcdb_combi_loss_override` returned None for keep_hot_facility=1/
   timer=1, leaning on the OLD flat-600 default. So flipping the default
   silently turned 190 corpus PCDB keep-hot-time-clock combis into
   no-keep-hot. Fixed to return the flat keep-hot row EXPLICITLY.

Key insight (the Summary is the input echo; the U985 keep-hot line is a
computed OUTPUT, so it must be derivable): keep-hot rides on the PCDB
boiler record (Table 105 keep_hot_facility/timer), resolved by
`pcdb_combi_loss_override`. A generic SAP-code combi with no PCDB record
(case 49, PCDF ref 0) has no keep-hot by construction → row 1. So the
default is not a guess — it is the spec-correct value for non-PCDB combis.

Worksheet-proven: case 49 → cost £726.696, SAP 72 — matching the
accredited worksheet to the digit (continuous 71.6945 = the worksheet's
own 71.6945). 000516 (keep-hot None) also exact (£860.716, SAP 63);
000490 (PCDB 10328, keep_hot_facility=1/timer=1) keeps its flat-600 via
the PCDB path. Masked until now because every prior combi-loss worksheet
fixture was keep-hot (000490/000474/000480 time-clock) or had V_d >= 100
every month (001431, rows coincide); case 49 is the first no-keep-hot one.

Corpus within-0.5 72.7% -> 73.3%, MAE 0.781 -> 0.774, PE 3.5 -> 3.4;
ratcheted _MAX_SAP_MAE 0.785 -> 0.775, _MAX_PE_PER_M2_MAE 3.6 -> 3.5.

Note: pyright strict type gate not run locally (pyright not installed).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-23 21:22:02 +00:00
..
__init__.py python upgraded due to enum 2026-06-12 15:47:28 +00:00
conftest.py python upgraded due to enum 2026-06-12 15:47:28 +00:00
test_client.py python upgraded due to enum 2026-06-12 15:47:28 +00:00
test_mapper_corpus.py python upgraded due to enum 2026-06-12 15:47:28 +00:00
test_mapper_dispatcher.py python upgraded due to enum 2026-06-12 15:47:28 +00:00
test_pv_battery_sap_neutrality.py test(pv-battery): pin SAP cost-neutrality on export-capable standard tariff 2026-06-14 09:51:34 +00:00
test_sap_accuracy_corpus.py fix(water-heating): derive combi keep-hot from the PCDB record, default no-keep-hot 2026-06-23 21:22:02 +00:00