HP Fault Rules
Heat pump fault detection rules (HP-*). Source grounding: HVAC FDD
Reference v1.0 ch.11 (Heat Pumps — adapted authority; see each card’s
Deviations section). Heat pumps extend the RTU fault set with defrost cycle
monitoring and reversing-valve diagnostics; refrigerant undercharge is the
most frequent fault (Barandier 2023).
Point dictionary: points/hp.points.json.
Index
| ID | Name | Sev | Method | Status |
|---|---|---|---|---|
| HP-0001 | COP degradation vs baseline | 3 | statistical | verified |
| HP-0002 | Defrost cycle anomaly | 3 | rule | verified |
| HP-0003 | Reversing valve fault | 2 | rule | verified |
| HP-0004 | Refrigerant undercharge (superheat/subcooling divergence) | 3 | rule | verified |
| HP-0005 | Refrigerant overcharge (subcooling high) | 3 | rule | verified |
| HP-0006 | Reversing-valve internal bypass leakage | 3 | rule | verified |
| HP-0007 | Heat-pump compressor proof-of-operation failure | 2 | rule | verified |
| HP-0008 | Auxiliary heat active above lockout with compressor running | 2 | rule | verified |
Severity and method for HP-0001..006 follow the reference’s ch.11 cards (its
§5.8.4 index carries no severity column); HP-0007 is a severity-2 library
proof-of-operation adaptation and HP-0008 is a library excess-energy adaptation.
HP-0001’s COP-vs-OAT baseline is host-fitted:
the host runs the 14-day learning regression and writes the slope/intercept as rule
parameters via set_param (R² > 0.6 precondition); the graph evaluates the
fitted line — the library’s first host-learned baseline.
Relationships
- HP-0001..008 share the heat-pump-faults playbook.
- RTU-0001 (compressor short-cycling) applies to HP equipment per its reference card. HP-0007 now supplies the per-compressor command/proof pair; defrost, pump-down, OEM permissives, and restart logic remain explicit host obligations.
- HP-0007 is related to every HP performance/refrigerant rule, but does not suppress them as a whole: fail-to-start can remove the running premise, while unexpected operation can leave their measurements meaningful.
- HP-0008 evaluates concurrent compressor and independently proven auxiliary heat only against the configured site lockout. HP-0001/0002/0007 lead the capacity, defrost, and proof branches without automatically silencing it.
Refrigerant-side family (library-authored, batch 17)
HP-0004/HP-0005/HP-0006 are grounded in NIST SP 1087 (2008) via the adapt-tier
program — the library’s first refrigerant-side rules, built on the
suction/liquid-line temperatures and host-derived saturation temperatures
(P-T lookup) landed in points/hp.points.json. All three replace the
source’s conditions-regressed no-fault baseline with fixed commissioning
placeholders (named simplification, RTU-0002 precedent). Wiring notes:
a charge cluster (HP-0004 trigger → HP-0001 member) and
HP-0001 suppressed_by: [HP-0004] are recorded candidates, left
unwired pending a decision on cross-family suppression conventions.