When a new restaurant prepares to open, every trade on site works towards one fixed deadline.
The kitchen equipment must be commissioned, electrical systems must be tested, extraction systems must operate safely, and environmental controls must be fully functional before the first customers arrive.
Unlike many commercial buildings, restaurant kitchens cannot operate without correctly balanced supply and extract ventilation. If the ventilation system shuts down, cooking equipment cannot be used safely, delaying opening and creating significant commercial consequences.
This was exactly the situation facing a new Slim Chickens restaurant in Colchester.
Only days before the planned opening, the kitchen ventilation control system repeatedly shut itself down. The issue became so disruptive that the site electricians temporarily bypassed the control panel simply to keep the ventilation system running.
Rather than replacing equipment or delaying the project, Partridge Ventilation called on iACS to investigate.
What followed was far more than a standard commissioning visit.
Our engineer diagnosed multiple installation faults, rewrote sections of the control strategy on site, re-engineered the actuator control philosophy, corrected field wiring and returned the complete ventilation system to fully automatic operation—allowing the restaurant to open on schedule.
What This Project Covered
This project demonstrates how iACS delivered:
- Commercial kitchen ventilation controls
- Kitchen supply and extract fan control
- Emergency HVAC troubleshooting
- Field wiring diagnostics
- Software reconfiguration
- Frost protection redesign
- Temperature sensor replacement
- 3-point valve control programming
- LPHW heating control
- Commercial kitchen commissioning
- Restaurant HVAC optimisation
Table of Contents
- Project Overview
- Why Commercial Kitchen Ventilation Is Critical
- The Kitchen Ventilation System
- The Challenge Before Opening Day
- Diagnosing the Real Cause
- Re-Engineering Frost Protection
- Correcting Temperature Sensor Installation
- Reprogramming the Heating Valve
- Correcting Field Wiring
- Final Commissioning
- Project Outcome
- Why This Project Matters
- Key Capabilities Demonstrated
- Looking for Specialist HVAC Commissioning?
1. Project Overview
Sector
Hospitality & Leisure
Application
Commercial Kitchen Ventilation
Customer
Partridge Ventilation Ltd
End User
Slim Chickens
Project
Restaurant Kitchen Ventilation Controls
Project Timeline
- Initial order: March 2024
- Site troubleshooting: August 2024
iACS Scope
- Kitchen ventilation panel supply
- Emergency troubleshooting
- Controller software modification
- Field wiring corrections
- Sensor replacement
- Heating control optimisation
- Final commissioning
Control Panel
iACS Kitchen Ventilation Panel
HVAC Equipment
- Kitchen supply fan
- Kitchen extract fan
- LPHW heating coil
- Systemair inverters
- Belimo differential pressure switches
- Duct temperature sensors
Project Status
Successfully commissioned and handed over.
2. Why Commercial Kitchen Ventilation Is Critical
Commercial kitchens create one of the most demanding HVAC environments.
Cooking equipment generates:
- Heat
- Grease
- Moisture
- Combustion products
- Odours
The ventilation system must continuously remove contaminated air while introducing tempered replacement air to maintain safe working conditions.
If either supply or extract ventilation fails, the kitchen cannot safely operate.
Unlike an office building where a temperature issue may simply cause discomfort, ventilation failure within a commercial kitchen can prevent the restaurant from opening altogether.
For this reason, reliable HVAC controls are just as important as the mechanical equipment itself.
3. The Kitchen Ventilation System
The restaurant utilised a dedicated kitchen ventilation system incorporating:
- Supply ventilation
- Extract ventilation
- Low Pressure Hot Water (LPHW) heating
- Systemair inverter drives
- Differential pressure monitoring
- Duct temperature sensing
The iACS Kitchen Ventilation Panel was responsible for coordinating every stage of operation.
Its duties included:
- Starting supply and extract fans
- Monitoring airflow
- Controlling the heating valve
- Protecting the heating coil from frost
- Monitoring alarms
- Automatically managing the complete ventilation sequence
The expectation was that the restaurant staff would simply operate the system without requiring technical intervention.
4. The Challenge Before Opening Day
Shortly before the restaurant was due to open, the ventilation system repeatedly shut itself down.
The problem became so disruptive that the site electricians bypassed the control panel entirely simply to keep the fans operating.
Although this temporarily restored ventilation, it removed much of the safety and automation built into the system.
The restaurant therefore required immediate technical support.
5. Diagnosing the Real Cause
Upon arriving on site, the iACS commissioning engineer carried out a systematic inspection.
Rather than finding a single fault, the investigation uncovered several installation issues.
These included:
- Missing frost protection
- Incorrectly positioned temperature sensor
- Faulty temperature sensor
- Incorrect heating valve actuator
- Heating actuator not installed
- Incorrect differential pressure wiring
Individually, each issue could have caused operational problems.
Together, they prevented the ventilation system from operating reliably.
Rather than issuing a list of defects and leaving site, iACS resolved each issue during the commissioning visit.
6. Re-Engineering Frost Protection
One of the most significant discoveries was that the frost thermostat had never been installed.
Normally, the frost thermostat protects the LPHW heating coil during cold weather.
Without this protection, the system risked freezing the water coil.
Replacing the frost thermostat at this stage would have required draining pipework and delaying the project.
Instead, the iACS engineer developed an alternative solution.
The controller software was reconfigured so that frost protection was provided using the supply air temperature sensor.
Rather than waiting for a missing hardware device, the software now generated a frost alarm whenever the supply temperature dropped below the required protection threshold.
This preserved the safety strategy without delaying the restaurant opening.
7. Correcting Temperature Sensor Installation
Further investigation revealed that the supply air temperature sensor had been installed incorrectly.
Instead of measuring the heated supply air leaving the coil, it had been positioned within the fresh air intake.
This meant the controller was attempting to regulate heating using outside air temperature.
The sensor itself had also been damaged during installation.
To resolve this, iACS:
- Supplied a replacement NTC10k sensor
- Relocated the sensor downstream of the heating coil
- Verified the new readings
- Recalibrated the controller
With accurate temperature feedback restored, the heating control immediately became more stable.
8. Reprogramming the Heating Valve
Perhaps the most interesting challenge involved the heating valve actuator.
The specified application required a modulating 0–10V actuator.
Instead, the mechanical installation included a simple ON/OFF actuator.
Replacing the actuator would have delayed the project.
Rather than requiring new hardware, iACS modified the software.
The controller was reprogrammed to drive the ON/OFF actuator as a 3-point floating actuator.
Using two digital outputs and carefully timed movement, the software could now position the valve progressively despite the actuator originally being intended only for open/close operation.
This innovative solution restored proportional heating control without replacing the actuator.
9. Correcting Field Wiring
The investigation also identified incorrect wiring on the differential pressure switch.
One conductor had been terminated incorrectly, causing repeated airflow failures.
After tracing the wiring and correcting the termination, the false airflow alarms disappeared.
This demonstrates how commissioning often extends far beyond software.
Successful HVAC systems depend equally on:
- Correct programming
- Correct sensors
- Correct wiring
- Correct installation
10. Final Commissioning
With the faults corrected, the original electrical bypasses were removed.
The iACS control panel was returned to full automatic operation.
The engineer then completed functional testing including:
- Supply fan testing
- Extract fan testing
- Heating demand verification
- Valve modulation testing
- Frost protection testing
- Temperature verification
- Alarm testing
Artificial heating demand was created to verify the newly programmed 3-point valve strategy.
The complete system operated successfully without nuisance alarms or shutdowns.
11. Project Outcome
Following the commissioning visit, the restaurant ventilation system was restored to normal automatic operation.
The completed solution delivered:
- Stable kitchen ventilation
- Reliable supply and extract fan operation
- Correct frost protection
- Accurate temperature control
- Fully operational heating valve modulation
- Correct differential pressure monitoring
- Alarm-free operation
The restaurant successfully opened using the fully commissioned iACS control system.
Partridge Ventilation subsequently confirmed that the system remained "up and running and working as expected."
Before and After the iACS Intervention
| Before | After |
| Control panel repeatedly shut down | Fully automatic operation restored |
| Ventilation bypassed | Full control functionality reinstated |
| Missing frost protection | Software-based frost protection implemented |
| Faulty sensor | New sensor installed and calibrated |
| Incorrect actuator | Reprogrammed as a 3-point floating actuator |
| Incorrect DP wiring | Wiring corrected and alarms eliminated |
| Opening at risk | Restaurant opened on schedule |
12.
Why This Project Matters
This project demonstrates that successful HVAC commissioning is about far more than simply checking whether equipment switches on.
Experienced controls engineers must understand:
- HVAC operation
- Software logic
- Mechanical systems
- Electrical wiring
- Sensors
- Actuators
- Heating systems
- Safety strategies
By combining all of these disciplines, iACS transformed a project that was days away from opening with repeated shutdowns into a fully functioning commercial kitchen ventilation system.
Rather than replacing equipment unnecessarily, intelligent engineering and software expertise delivered a practical solution that saved both time and cost.
13. Key Capabilities Demonstrated
- Commercial kitchen HVAC controls
- Emergency troubleshooting
- Controller software modification
- Frost protection redesign
- Sensor replacement
- Temperature calibration
- 3-point valve programming
- Field wiring correction
- Commercial kitchen commissioning
- HVAC fault diagnosis
Looking for Specialist Commercial Kitchen HVAC Controls?
Commercial kitchens leave little room for error.
Whether you're installing a new restaurant, upgrading an existing ventilation system or facing unexpected commissioning challenges, iACS provides practical engineering solutions backed by decades of HVAC controls experience.
Our services include:
- Kitchen ventilation controls
- AHU controls
- Fan Coil Unit controls
- Software development
- HVAC commissioning
- Site troubleshooting
- Sensor calibration
- Control panel design
- HVAC optimisation
From independent restaurants to national hospitality brands, iACS helps customers deliver reliable, energy-efficient HVAC systems that perform exactly as intended.