Commercial HVAC Controls Replacement & Energy Optimization Upgrade
Ag Workers Mutual Insurance Co. – EMS Controls & VFD Modernization Case Study (Texas)
Project Overview (Controls Failure After Mechanical Upgrade)
Following recent condenser upgrades at Ag Workers Mutual Insurance Co., system startup revealed critical issues with the existing building control system performance.
The legacy Barber-Colman control system was no longer functioning properly and was no longer supported, resulting in widespread operational failures across HVAC zones.
B.I.M.S. was contracted to resolve control system deficiencies and restore proper coordination between HVAC equipment, including zoning, condensers, and electric heat operation.
Control System Problems Identified
After mechanical upgrades were completed, the following control issues were discovered:
- Damper actuators not positioning correctly across zones
- Inability to properly stage or control condenser operation
- Electric heat strips not responding correctly to demand signals
- Lack of coordinated system-wide control logic
- Legacy Barber-Colman system no longer supported or serviceable
- Inefficient system operation causing continuous or near-continuous cooling
- Equipment running outside of intended design parameters
- Increased risk of premature equipment wear due to improper control sequencing
These failures resulted in poor comfort control, excessive energy consumption, and unnecessary equipment stress.
Engineering Solution Implemented
To correct these issues, B.I.M.S. implemented a full controls modernization and HVAC efficiency upgrade, replacing both control logic and mechanical drive components.
1. EMS Controls Replacement (Automated Logic System)
The outdated Barber-Colman system was replaced with a modern Automated Logic Energy Management System (EMS) tailored specifically to the facility.
The new system provided:
- Full building HVAC system integration
- Accurate zone damper control and sequencing
- Proper condenser staging and operation
- Coordinated control of electric heat strips
- Custom programming based on building load characteristics
- Improved system visibility and operational feedback
This allowed the building to transition from reactive control to intelligent, demand-based HVAC operation.
2. VFD Upgrade & Airflow Optimization
To improve system efficiency and motor reliability, B.I.M.S. upgraded the blower system with:
- VFD-rated motor upgrade
- Variable Frequency Drive (VFD) installation
- New drive pulleys
- New banded belt system
This allowed for:
- Adjustable airflow based on building demand
- Reduced energy consumption during partial load conditions
- Improved motor longevity and reduced mechanical stress
- More precise temperature and comfort control
Results & Energy Performance Improvements
Following the EMS and VFD upgrade, the facility achieved:
- Restored proper zone damper operation and airflow control
- Correct condenser and electric heat sequencing
- Elimination of uncontrolled continuous cooling operation
- Significant reduction in wasted energy consumption
- Improved comfort stability across occupied zones
- Reduced mechanical wear caused by improper control logic
- Estimated substantial energy savings due to elimination of 24/7 overcooling conditions
The customer reported that prior to the upgrade, the building was effectively cooling continuously due to control failure, leading to excessive energy use and equipment stress.
Key Technical Insight
This project highlights a critical HVAC controls principle:
Mechanical upgrades alone cannot deliver efficiency without a functional and intelligent control system.
In this case, system inefficiencies were caused by:
- Unsupported legacy controls platform (Barber-Colman)
- Lack of coordinated zone control
- Improper equipment sequencing
- No dynamic airflow or load response strategy
Replacing the control system and adding VFD-driven airflow control allowed the entire HVAC system to operate as a coordinated, demand-driven system instead of static equipment operation.
Conclusion
B.I.M.S. successfully completed a full HVAC controls and efficiency modernization at Ag Workers Mutual Insurance Co., restoring proper system operation and significantly improving energy performance.
The final solution included:
- Replacement of legacy Barber-Colman controls with Automated Logic EMS
- Full HVAC zoning and equipment coordination restoration
- VFD motor and airflow optimization upgrade
- Improved system efficiency and reduced operational waste
This project represents a complete transition from outdated, uncontrolled HVAC operation to a modern, intelligent building automation system designed for long-term efficiency and reliability.