Sequence fault — Chiller → CW (CC) pump.

Trigger, action plan, and escalation criteria.

Related metric

chiller_plant_operational_compliance

Trigger

system_on=1 AND cc_any_on=0 sustained ≥ seq_fail_duration (raises SEQ-FAIL Chiller→CC)

Value drivers

Asset lifespan Energy savings Avoided truck rolls

Preconditions

Chiller ON/OFF and CC-pump run/proven status mapped as Modbus binary points and rolled up into system_on and cc_any_on. Interlock #02 confirmed to apply to the plant before the alarm is armed. seq_fail_duration is a configurable server-side attribute; the chiller ON/OFF Modbus mapping is confirmed per plant.

Human role

Primary — Keedian reads the interlock and raises the alarm; the BMS sequence-logic correction is the plant-service vendor's. Operators confirm the fault, notify the customer, and coordinate the vendor referral.

Action plan

(1) Point-mapping sanity check first — confirm the chiller-ON and CC-pump-proven points are current and correctly mapped before treating the fault as real; a stale point manufactures a false SEQ-FAIL. (2) Confirm the condition is sustained past seq_fail_duration, not a staging transient. (3) Once confirmed, notify the customer and the plant-service vendor out of cycle — with no condenser flow the chiller is heading toward high head pressure and a high-pressure trip. (4) Attribute the fault to the specific chiller / CC-pump pair; Keedian surfaces the finding and recommended correction, the vendor changes the sequence logic on the BMS side.

Escalation

(1) Chiller confirmed running with no proven condenser-water flow → out-of-cycle customer + plant-vendor alert before a high-pressure trip; do not hold for the MBR. (2) Recurrence on the same plant after correction → flag a controls or sensor fault for a deeper vendor engagement. (3) Status feed unreliable / point mapping unconfirmed → pause plant compliance reporting until the mapping is reconciled.

Prevention

(1) Verify every chiller-ON and CC-pump-proven point at onboarding and confirm interlock #02 applies before arming the alarm. (2) Calibrate seq_fail_duration to ride through staging but catch a genuine loss of condenser flow. (3) Log recurring faults per plant to surface a developing controls or sensor issue for the vendor.