Point Dictionary: RTU

RTU (packaged rooftop unit) point dictionary. Shared air-side points carry their Brick classes and 223P patterns from the AHU dictionary (see per-point notes); the owning equipment class is brick:Rooftop_Unit / brick:RTU (both verified in Brick 1.4.4). RTU-specific points (comp_status, comp_stage, htg_status) are grep-verified against Brick 1.4.4 but have no reference-model instance check, hence provisional. ASHRAE 223 mappings are pinned to the public-review artifact 223p-1.0.0-ppr2.1.ttl (owl:versionInfo 1.0.0-ppr.2.1; SHA-256 1f156f9938c0be430d2216e01e31bb183c438ba318d8d4a23d2f074ebcd6f573), not an inferred final 2026 release. That artifact imports QUDT 3.1.8; the quantity-kind and unit local names here were independently checked against the repository-declared QUDT 3.1.4 artifacts.

sat

Supply (discharge) air temperature

• 223P: Sensor observes QuantifiableObservableProperty attached to the AHU supply-air OutletConnectionPoint
• QUDT unit: DEG_C

Brick Discharge_Air_Temperature_Sensor is brick:aliasOf this class. 223P pattern verbatim from reference instance MultipleZoneAhu-sa-temp; medium comes from hasMedium on the owning ConnectionPoint. [RTU dictionary] Brick point class and 223P property pattern are equipment-independent and carried from the AHU dictionary, where instance-level verification was done against the AHU reference model; here the owning equipment is brick:Rooftop_Unit (alias RTU, verified in Brick 1.4.4) and no packaged-unit reference instance has been checked, so treat the 223P attachment as pattern guidance.

sat_sp

Active supply (discharge) air temperature setpoint used by this RTU

• 223P: QuantifiableActuatableProperty linked from the observed supply-air temperature property via hasSetpoint
• QUDT unit: DEG_C

Supply_Air_Temperature_Setpoint is exact in Brick 1.4.4. PPR2.1 QuantifiableActuatableProperty, Temperature, DEG_C, Fluid-Air, Aspect-Setpoint, and hasSetpoint are exact and follow the public G36 supply-air-temperature setpoint pattern. Bind the final active mode-specific RTU target; an occupied default or cooling-only constant is invalid during heating.

mat

Mixed air temperature (after OA and RA mix)

• 223P: Sensor observes QuantifiableObservableProperty located topologically downstream of the OA/RA mixing junction via hasObservationLocation
• QUDT unit: DEG_C

223P has no mixed-air role or aspect (EnumerationKind-Role has 21 members, none mixed-air); the reference model disambiguates purely by observation location. A property-only export loses the ‘mixed’ semantics — topology must accompany it. [RTU dictionary] Brick point class and 223P property pattern are equipment-independent and carried from the AHU dictionary, where instance-level verification was done against the AHU reference model; here the owning equipment is brick:Rooftop_Unit (alias RTU, verified in Brick 1.4.4) and no packaged-unit reference instance has been checked, so treat the 223P attachment as pattern guidance.

oat

Outdoor air temperature

• 223P: Sensor observes QuantifiableObservableProperty at the outdoor-air intake
• QUDT unit: DEG_C

Brick spelling is Outside_ (Outdoor_Air_Temperature_Sensor does not exist). Role-OutdoorAirIntake is 223P’s only outdoor role; used by reference instance oa-temp. [RTU dictionary] Brick point class and 223P property pattern are equipment-independent and carried from the AHU dictionary, where instance-level verification was done against the AHU reference model; here the owning equipment is brick:Rooftop_Unit (alias RTU, verified in Brick 1.4.4) and no packaged-unit reference instance has been checked, so treat the 223P attachment as pattern guidance.

rat

Return air temperature

• 223P: Sensor observes QuantifiableObservableProperty at the AHU return-air InletConnectionPoint
• QUDT unit: DEG_C

Verbatim from reference instance MultipleZoneAhu-ra-temp. [RTU dictionary] Brick point class and 223P property pattern are equipment-independent and carried from the AHU dictionary, where instance-level verification was done against the AHU reference model; here the owning equipment is brick:Rooftop_Unit (alias RTU, verified in Brick 1.4.4) and no packaged-unit reference instance has been checked, so treat the 223P attachment as pattern guidance.

oa_dmpr_cmd

Outdoor air damper command (0 = closed, 100 = full open)

• 223P: QuantifiableActuatableProperty on the Damper via hasProperty; Actuator actuates the damper
• QUDT unit: PERCENT

Attach via isPointOf to brick:Outside_Damper or Economizer_Damper. In the 223P reference model the damper equipment carries hasRole Role-Economizer (Role-OutdoorAirIntake for a non-economizer minimum-OA damper). Verified at g36:DamperOrShape1 and instance MultipleZoneAhu-economizer-oa-damper-command. [RTU dictionary] Brick point class and 223P property pattern are equipment-independent and carried from the AHU dictionary, where instance-level verification was done against the AHU reference model; here the owning equipment is brick:Rooftop_Unit (alias RTU, verified in Brick 1.4.4) and no packaged-unit reference instance has been checked, so treat the 223P attachment as pattern guidance.

sf_cmd

Final command requesting operation of this RTU supply fan

• 223P: EnumeratedActuatableProperty on the supply Fan via hasProperty

Attach brick:Start_Stop_Command to brick:Supply_Fan. PPR2.1 g36:Fan and the public MultipleZoneAhu supply-fan instance attest the Binary-OnOff actuatable property; the fan carries Role-Supply. Unit enable is invalid unless demonstrably identical to the final fan output.

sf_status

Independent run proof for this RTU supply fan

• 223P: EnumeratedObservableProperty on the Fan via hasProperty

Attach via isPointOf to brick:Supply_Fan. Deliberately not brick:Run_Status — its inherited definition routes equipment run status to the On/Off branch. 223P: hasEnumerationKind Binary-OnOff (OnOff-On/OnOff-Off), verified at instance MultipleZoneAhu-sa-fan-start-status; fan carries hasRole Role-Supply. [RTU dictionary] Brick point class and 223P property pattern are equipment-independent and carried from the AHU dictionary, where instance-level verification was done against the AHU reference model; here the owning equipment is brick:Rooftop_Unit (alias RTU, verified in Brick 1.4.4) and no packaged-unit reference instance has been checked, so treat the 223P attachment as pattern guidance. RTU-0010 requires this proof to describe the same physical supply fan as sf_cmd; command echo is invalid.

occ_schedule

Occupancy schedule state (true = scheduled occupied)

• 223P: EnumeratedObservableProperty (EnumeratedActuatableProperty if the schedule writes to the controller) on the Zone or AHU

Neither ontology has a schedule concept. Brick three-way choice by point direction: Occupancy_Command (schedule output driving the unit — our reading), Occupied_Mode_Status (mode read-back), Occupancy_Status (physical room occupancy — wrong here). 223P occupancy enumeration verified from the g36:Zone SHACL shape (Occupied-True/Occupied-False). [RTU dictionary] Brick point class and 223P property pattern are equipment-independent and carried from the AHU dictionary, where instance-level verification was done against the AHU reference model; here the owning equipment is brick:Rooftop_Unit (alias RTU, verified in Brick 1.4.4) and no packaged-unit reference instance has been checked, so treat the 223P attachment as pattern guidance.

comp_status

Independent run proof for the bound RTU compressor or compressor scope

• 223P: EnumeratedObservableProperty on the Compressor via hasProperty

Brick 1.4.4 On_Off_Status and Compressor are exact generic classes; PPR2.1 EnumeratedObservableProperty and Binary-OnOff are exact, but no public compressor-property instance was found, so the attachment remains provisional. Default to one compressor/circuit for RTU-0001. An any-running OR is allowed for rules that explicitly need aggregate operation, but it must be documented and hides starts or failures while another compressor remains on.

comp_stage

Active compressor stage (0 = off, 1..N = stage index)

• QUDT unit: UNITLESS

brick:Stages_Status is verified in Brick 1.4.4 (‘Indicates which stage a control loop or equipment is in’) - an exact fit. Second integer point in the library (after operating_state); stage 0 means no compressor running. RTU-0002 interprets stages 1 and 2 against per-stage baselines and reports stages outside {1,2} as not evaluable via its yStageOk output; hosts with more stages extend by rebinding the baseline constants. No standard PPR2.1 EnumerationKind defines this site-specific integer stage encoding, so the s223 mapping is null until a deployment supplies a custom enumeration.

htg_status

Heating stage run status (true = gas/electric heat or heating coil active)

• 223P: EnumeratedObservableProperty on the heating element (burner, electric heater, or coil) via hasProperty

brick:Heating_Start_Stop_Status verified in Brick 1.4.4 (subclass of Start_Stop_Status). Alternative for sites tagging the element itself: generic On_Off_Status isPointOf the burner/heater equipment. For staged gas heat bind the OR of stage statuses - RTU-0003 only asks whether ANY heat is active.

cond_leaving_temp

Condenser leaving air temperature (air discharged off the condenser coil)

• 223P: Sensor observes a QuantifiableObservableProperty at the condenser-air OutletConnectionPoint
• QUDT unit: DEG_C

No exact Brick 1.4.4 class found for condenser LEAVING air (brick: null, refrigerant-side precedent from the hp dict). Most packaged RTUs lack this sensor — the original deferral reason for RTU-0007; a strap-on or discharge-plenum probe retrofit is the usual binding. Condenser split = cond_leaving_temp − oat.

cond_split_baseline

Expected condenser air-temperature split for the current compressor stage and OAT (host-fitted baseline)

• 223P: Host baseline Function hasOutput a QuantifiableProperty
• QUDT unit: K

HOST-DERIVED virtual point (evap_sat_temp / zone_reheat_fraction precedent): the reference’s baseline_condenser_split(comp_stage, oat) — a per-stage curve against OAT fitted from known-clean operation. The host documents the fit window and guarantees the published value is strictly positive (RTU-0007 divides by it). This is the two-variable baseline that originally deferred the fault; publishing the fit as an ordinary point resolves it.

suction_temp

Compressor suction line refrigerant temperature (surface-mount acceptable)

• 223P: Sensor observes a QuantifiableObservableProperty at the Compressor suction ConnectionPoint
• QUDT unit: DEG_C

Mirror of the hp dict entry (duplicated per the lint’s own-family resolution rule; same derivation/placement obligations). Consumed by the RTU-0008/0009 charge pair — superheat = suction_temp − evap_sat_temp, subcooling = cond_sat_temp − liquid_temp. Original hp note: No Brick 1.4.4 suction-temperature class (only Refrigerant_Level_Sensor exists refrigerant-side); null mapping per defrost_status precedent. Superheat = suction_temp - evap_sat_temp.

liquid_temp

Liquid line refrigerant temperature (surface-mount acceptable)

• 223P: Sensor observes a QuantifiableObservableProperty at the condenser liquid-line outlet ConnectionPoint
• QUDT unit: DEG_C

Mirror of the hp dict entry (duplicated per the lint’s own-family resolution rule; same derivation/placement obligations). Consumed by the RTU-0008/0009 charge pair — superheat = suction_temp − evap_sat_temp, subcooling = cond_sat_temp − liquid_temp. Original hp note: No Brick 1.4.4 class; null mapping. Subcooling = cond_sat_temp - liquid_temp.

evap_sat_temp

Evaporating saturation temperature (HOST-DERIVED: suction pressure via refrigerant P-T lookup, or coil-surface proxy)

• 223P: Function hasOutput a QuantifiableProperty derived from refrigerant pressure and a refrigerant-specific pressure-temperature relation
• QUDT unit: DEG_C

Mirror of the hp dict entry (duplicated per the lint’s own-family resolution rule; same derivation/placement obligations). Consumed by the RTU-0008/0009 charge pair — superheat = suction_temp − evap_sat_temp, subcooling = cond_sat_temp − liquid_temp. Original hp note: HOST-DERIVED virtual point (zone_reheat_fraction/chw_valve_max precedent): the P-T relationship is refrigerant-specific and lives at the host, never in a rule graph. Derivation MUST match the site’s refrigerant.

cond_sat_temp

Condensing saturation temperature (HOST-DERIVED: discharge/liquid pressure via refrigerant P-T lookup)

• 223P: Function hasOutput a QuantifiableProperty derived from refrigerant pressure and a refrigerant-specific pressure-temperature relation
• QUDT unit: DEG_C

Mirror of the hp dict entry (duplicated per the lint’s own-family resolution rule; same derivation/placement obligations). Consumed by the RTU-0008/0009 charge pair — superheat = suction_temp − evap_sat_temp, subcooling = cond_sat_temp − liquid_temp. Original hp note: HOST-DERIVED virtual point, same convention and refrigerant caveat as evap_sat_temp.