Modern fulfilment centres operate continuously, processing thousands of deliveries every day while maintaining comfortable working environments for employees and reliable conditions for automated equipment.
Behind the scenes, Air Handling Units play a critical role in maintaining these environments. However, on large infrastructure projects it is increasingly common for the mechanical plant to be supplied by multiple Air Handling Unit manufacturers, each with their own preferred hardware, wiring methods and control philosophies.
While this approach can offer procurement flexibility, it often creates significant challenges for Building Management System integration, commissioning and long-term maintenance.
For this project, iACS partnered with Air Handlers Northern Ltd and Mansfield Pollard to deliver a common HVAC controls platform across multiple large-scale AHUs serving a major logistics fulfilment centre in London.
By standardising the controls, communications and software architecture across every unit, iACS delivered a consistent control strategy regardless of which manufacturer supplied the mechanical equipment.
The result was a unified HVAC controls solution capable of providing seamless Building Management System integration, simplified commissioning and long-term operational consistency across the entire facility.
What This Project Covered
This project demonstrates how iACS delivered:
- Multi-OEM AHU controls
- Standardised HVAC control architecture
- Bespoke iSMART control panels
- Carel pCO5+ programmable controllers
- BACnet MS/TP integration
- Modbus RS485 integration
- EC fan control
- Duty and Standby fan sequencing
- Thermal wheel and cross-flow heat recovery
- DX cooling integration
- Thyristor-controlled electric heating
- Belimo actuator integration
- Site installation
- Commissioning
- Advanced software troubleshooting
Table of Contents
- Project Overview
- Why Logistics Facilities Need Standardised Controls
- The Air Handling Unit Configuration
- The Challenge of Multi-OEM Projects
- The iACS Standardised Control Solution
- Unified Building Management System Integration
- Duty & Standby Fan Strategies
- Precision Electric Heater Control
- Solving a Complex Duty/Standby Fan Fault
- Commissioning & Functional Testing
- Project Outcome
- Why This Project Matters
- Key Capabilities Demonstrated
- Looking for a Standardised AHU Controls Partner?
1. Project Overview
Sector
Logistics & E-Commerce
Application
Fulfilment Centre Ventilation
Direct Customers
- Air Handlers Northern Ltd
-
Mansfield Pollard
End User
A leading global e-commerce provider.
Project Location
London
Project Timeline
- Orders placed between December 2025 and January 2026
-
Installation and commissioning completed during 2026
iACS Scope
- iSMART control panel manufacture
- Controller programming
- Site installation
- Commissioning
- Belimo field device supply
- BACnet integration
- Modbus integration
- Software optimisation
-
Technical support
Control Platform
Multiple iSMART control panels built around the Carel pCO5+ controller platform.
Project Status
Successfully installed and commissioned.
2. Why Logistics Facilities Need Standardised Controls
Large logistics facilities rarely consist of a single Air Handling Unit.
Instead, multiple AHUs operate across warehouses, offices, welfare facilities and technical spaces.
When these units are supplied by different manufacturers, facilities teams can quickly encounter problems such as:
- Different user interfaces
- Different alarm structures
- Different software philosophies
- Different communication methods
- Increased commissioning complexity
- Difficult BMS integration
- Increased maintenance costs
Rather than accepting these inconsistencies, the project team standardised the controls across every AHU using the iACS iSMART platform.
This ensured every unit behaved consistently regardless of the mechanical manufacturer.
3. The Air Handling Unit Configuration
The project included multiple large-scale Air Handling Units with varying mechanical configurations.
Typical equipment included:
- Variable-speed EC fans
- Thermal wheel heat recovery
- Cross-flow heat recovery
- DX cooling
- Electric reheaters up to 18kW
- Differential pressure switches
- Belimo actuators
- BACnet communications
- Modbus communications
Although the mechanical configurations differed slightly between manufacturers, the controls philosophy remained consistent throughout the project.
4. The Challenge of Multi-OEM Projects
Supplying AHUs from multiple manufacturers offers flexibility during procurement but can introduce significant challenges once installation begins.
Without a common controls platform, contractors often face:
- Different controller hardware
- Different software structures
- Different BMS mappings
- Different commissioning methods
- Different alarm behaviours
This creates unnecessary complexity for:
- Building Management System integrators
- Commissioning engineers
- Maintenance teams
- Facilities managers
The engineering objective for this project was therefore straightforward:
Create one common controls architecture across every Air Handling Unit.
5. The iACS Standardised Control Solution
iACS designed a suite of bespoke iSMART control panels tailored to each manufacturer's AHU while maintaining a common software foundation.
The solution included:
- Carel pCO5+ Small controllers
- pGD1 user displays
- Native BACnet MS/TP
- Native Modbus RS485
- Belimo field devices
- Differential pressure switches
- EC fan control
- Thyristor-controlled electric heating
Regardless of which AHU manufacturer supplied the mechanical equipment, every unit shared the same overall operating philosophy, making commissioning and future maintenance considerably simpler.
6. Unified Building Management System Integration
One of the primary benefits of standardising the controls was seamless Building Management System integration.
Every AHU communicated using:
- BACnet MS/TP
- Modbus RS485
This provided facilities teams with a consistent interface for:
- Temperatures
- Fan speeds
- Alarms
- Operating modes
- Heat recovery
- Heater demand
- Filter monitoring
- Damper positions
Rather than integrating several different proprietary control platforms, the BMS interacted with one consistent controls philosophy across the entire site.
Advanced Heat Recovery & Cooling Control
The AHUs incorporated several energy-efficient technologies.
These included:
Thermal Wheel Heat Recovery: Recovering heat from extract air to reduce heating demand.
Cross Flow Heat Recovery: Providing efficient energy transfer while maintaining air separation.
DX Cooling: Delivering responsive cooling during higher load conditions.
Electric Reheaters: Large electric heaters provided supplementary heating where required.
7. Precision Electric Heater Control
Some Air Handling Units incorporated electric reheaters rated up to 18kW.
Rather than switching these heaters in large stages, iACS integrated solid-state thyristor control.
This allowed the heating output to modulate smoothly between 0% and 100%.
The advantages included:
- Stable temperature control
- Reduced electrical stress
- Improved comfort
- Reduced temperature overshoot
- Better energy efficiency
This type of proportional control is particularly valuable in large commercial ventilation systems where maintaining stable supply air temperatures is essential.
8. Duty & Standby Fan Strategies
Several AHUs incorporated duty and standby fan arrangements.
This strategy improves system resilience by allowing one fan to automatically replace another in the event of a fault.
The sequence required the controller to:
- Detect the primary fan failure.
- Start the standby fan.
- Verify airflow.
- Monitor pressure.
- Confirm successful changeover.
This provides redundancy without interrupting ventilation.
Solving a Complex Duty/Standby Fan Fault
During commissioning, one AHU experienced an unusual issue.
When the duty return fan was intentionally failed, the standby fan started immediately.
However, the mechanical backdraught damper required several seconds to open.
Because the fan could not immediately establish airflow, the controller interpreted the condition as a failed fan and generated a "Fan Flow Failed" alarm.
Although the controller was operating exactly as programmed, the software timing no longer matched the mechanical characteristics of the installation.
Rather than modifying the mechanical equipment, iACS remotely reviewed the application and adjusted the software.
The start-up alarm delay was increased to match the opening time of the backdraught damper.
Once the revised timing was applied:
- False alarms disappeared.
- Duty/standby changeovers operated correctly.
- The failover sequence remained fully protected.
This demonstrated how intelligent software refinement can resolve complex electro-mechanical interactions without requiring physical modifications.
9. Solving a Complex Duty/Standby Fan Fault
During commissioning, one AHU experienced an unusual issue.
When the duty return fan was intentionally failed, the standby fan started immediately.
However, the mechanical backdraught damper required several seconds to open.
Because the fan could not immediately establish airflow, the controller interpreted the condition as a failed fan and generated a "Fan Flow Failed" alarm.
Although the controller was operating exactly as programmed, the software timing no longer matched the mechanical characteristics of the installation.
Rather than modifying the mechanical equipment, iACS remotely reviewed the application and adjusted the software.
The start-up alarm delay was increased to match the opening time of the backdraught damper.
Once the revised timing was applied:
- False alarms disappeared.
- Duty/standby changeovers operated correctly.
- The failover sequence remained fully protected.
This demonstrated how intelligent software refinement can resolve complex electro-mechanical interactions without requiring physical modifications.
10. Commissioning & Functional Testing
Each Air Handling Unit underwent a structured commissioning process.
Activities included:
- Pre-commissioning inspections
- Functional testing
- Controller verification
- Fan testing
- Heater testing
- Communication testing
- Alarm verification
- Duty/standby testing
- Heat recovery checks
Following successful testing, the installations were signed off and handed over.
Flexible Project Delivery
One of the strengths of this project was the flexibility of the engineering support.
For Air Handlers Northern, iACS supplied the control panels and completed the software commissioning.
For Mansfield Pollard, the scope extended further to include:
- Site installation
- Field device installation
- Electrical integration
- Commissioning support
This demonstrated iACS's ability to adapt its services to suit each customer's preferred delivery model.
11. The Project Outcome
By standardising the controls across multiple Air Handling Unit manufacturers, the project achieved:
- Consistent HVAC control philosophy
- Unified Building Management System integration
- Reliable communications
- Stable duty/standby operation
- Precision heater control
- Simplified maintenance
- Successful commissioning
The software refinement also eliminated the false duty/standby alarms, ensuring reliable long-term operation.
The completed installation delivered a common controls architecture across the entire fulfilment centre despite the mechanical equipment originating from multiple manufacturers.
Before and After the Project
| Challenge | iACS Solution |
| Multiple AHU manufacturers | Standardised iSMART controls |
| Different control philosophies | Unified software platform |
| Complex BMS integration | Native BACnet & Modbus communications |
| High-capacity electric heating | Smooth thyristor modulation |
| False duty/standby alarms | Software timing optimisation |
| Multiple installation scopes | Flexible engineering support |
12.
Why This Project Matters
Large logistics facilities increasingly rely on multiple mechanical suppliers.
Without a common controls strategy, long-term operation can quickly become difficult to manage.
This project demonstrates how iACS provides a consistent control architecture regardless of who manufactures the Air Handling Unit.
By combining programmable controllers, intelligent software, open communications and responsive engineering support, iACS delivered a solution that simplified commissioning while providing long-term operational consistency.
13. Key Capabilities Demonstrated
- Multi-OEM AHU controls standardisation
- Carel pCO5+ programming
- Duty & standby fan strategies
- Advanced software troubleshooting
- BACnet MS/TP integration
- Modbus RS485 integration
- Thyristor-controlled electric heating
- Belimo actuator integration
- Site installation
- Commissioning
- Remote software optimisation
- Flexible project delivery
Looking for a Standardised AHU Controls Partner?
Whether you're delivering a logistics hub, manufacturing facility, commercial development or any project involving multiple AHU manufacturers, iACS can help simplify your controls strategy.
Our expertise includes:
- AHU controls
- iSMART and intelligent HVAC platforms
- Multi-OEM standardisation
- BACnet & Modbus integration
- EC fan control
- Duty/standby strategies
- Heat recovery optimisation
- Electric heater control
- Commissioning
- Technical support
By standardising the controls across your project, iACS helps reduce commissioning complexity, improve long-term maintainability and deliver a consistent HVAC platform regardless of the mechanical equipment supplier.