When make-up air is included as part of a commercial kitchen ventilation system, there are some important considerations to keep in mind to ensure make-up units are functioning properly and efficiently. Make-up air unit commissioning for new projects or pre-existing buildings is an invaluable quality assurance step to verify and document that HVAC systems function as specified and meet the operational savings, enhanced unit performance and prevention of costly service calls or repairs.
The Commissioning Process:
Commissioning a make-up air unit should always begin with a certified technician or licensed agent inspection of the unit, its components and the installation to verify everything was installed correctly and meets the design requirements. Your tech will follow the OEM startup instructions delivered with the unit, including a manual, wiring diagram and checklist with space for initial start-up documentation. Tempered units with heating or cooling capability also come with a quick-start guide to assist with unit adjustments and start-up.
Figure 1 shows examples of the Accurex Quick Start Guide and XDGX Submittal Drawings for Direct Gas Make-up Air units for step-by-step instructions and convenient reference.
Quick Start Guide XDGX Example - Submittal Drawings
Importance of Air Balancing
Prior to initial start-up of a make-up air unit, one of the most important details your technician will verify is proper air balancing and adjustment according to contract documents or schedules. This involves testing, adjusting and balancing (TAB) the following:
- Measurement of air
- Measurement of CFM output
- Adjustment of dampers and valves
- Setting of sensors
- Airflow adjustments
A range of complexities can exist within your unique space, making it all the more important for a qualified tech to complete your air balancing and commissioning service.
Some additional challenges identified by a TAB inspection include:
- Difficulty opening external building doors due to negative pressure applied from the inside-out
- External doors stay open slightly due to an over-pressurized building
- Over current of the fan motor, causing make-up air unit circuit tripping or an alarm to sound
- Undersized ducts
- Duct blockages
- Ductwork with multiple or sharp turns
Advantages of Proper Startup and Commissioning
Your commercial kitchen applications require important start-up and commissioning. However, TAB and unit commissioning may not be standard practice in many instances. Smaller projects may not have technicians familiar with make-up air start-up and operation. Thus, make-up air units may not operate correctly when installed without the proper start-up procedures being followed resulting in unsatisfactory performance.
Here are a few avoidable technical and customer service issues identified by make-up air start-up:
• Heating capability compromised by not reaching design temperature rise
• Over heating/cooling a space or short cycling
• Increased operating costs due to excessive outside air above schedule requirements
• Ignition failure or low flame signal due to burner pressure differential
• Refrigerant system failure due to sub-cool and superheat temperatures
• Unit system communication issues or no control of the unit caused by failed installation of field wiring
Commissioned make-up air units avoid operational issues and perform more efficiently creating fewer operating costs. In fact, studies conducted by Portland Energy Conservation, Inc. (PECI) show average operating costs of commissioned buildings ranged from 8 to 20% below that of non-commissioned buildings. Proper start-up and commissioning are critical to ensuring your make-up air unit is operating as expected while providing in-depth documentation to aid in future service or warranty concerns. Connect with a local expert to request this service and ensure proper HVAC systems function.
Learn more about Accurex Make-Up Air Units here
