Enhanced Prioritization – Return Fan Cycling Excessively
Objective/Method/Outcome
Objective: Determines if the return fan is changing more than expected
Method: Normalizes the Binary and Analog Samples to determine if they are being cycled more than the acceptable amount of time. The Potential Savings are determined by calculating the annual cost of cycling subtracted by the cost to replace equipment.
Outcome: Triggers an insight, and calculates the potential savings.
Description
Analyzes equipment state changes using Analog or Binary trend log, triggering an insight when daily cycles exceeds a threshold.
This rule is part of the CopperTree Standard rule-set.
Default Priority
Medium
Diagnosis
Check and revise programming and sequence of operation to prevent unnecessary equipment cycling.
Message
Return fan is cycling more often than expected.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Logic
Inputs
| Input | Unit | Tags | Description |
|---|---|---|---|
| Equip Command Or Amperage | Return Air Fan Status, Return Air Fan Command | The recorded status of the fan | |
| Threshold – PropertyImpact Weekly | The minimum weekly property impact that can trigger insight | ||
| Threshold – UrgencyScore WeeklyMax | The maximum urgency score that the rule can assign | ||
| Cost to Replace Equipment | $ | ||
| Expected Equipment Lifetime | Years | ||
| Annual Days of Operation | The yearly days the system is operational | ||
| Threshold – Analog Cycle Delta | The acceptable analog change | ||
| Threshold – Daily Cycles | The acceptable daily analog cycles |
Notes
Urgency Score is a measure of how urgent the fault is and a high score denotes critical adverse impact on the equipment. Urgency Score is scaled so that if the number of cycles is equal to or less than the Daily Cycles Threshold, the score is 0. If the number of cycles per day is twice that of the Daily Cycles Threshold, the score is 100. The maximum score of the week is used to trigger the Insight.
Property Impact is calculated as the number of days during the week where the cycle count was higher than threshold (expresses in percent of total days being monitored in the week)
Default values for constants:
- Threshold – Analog Cycle Delta: 1
- Threshold – PropertyImpact Weekly: 14
- Threshold – UrgencyScore WeeklyMax: 30
- Threshold – Daily Cycles: 20