HVAC System Commissioning
HVAC Systems Have To Be Commissioned
A big mistake many HVAC contractors make is assuming if they follow a Manual D or engineered design the HVAC system is ready to go right out of the box. It is critical the system be commissioned and balanced after the installation has been completed. A common misconception is the design is the only aspect of the system.
What Is HVAC Commissioning?
HVAC commissioning is ensuring the system is operating per the design and the equipment is operating per the manufacturer’s specifications. Commissioning also requires verification that all of the building’s components interact well so that one piece of equipment does not cause unintended consequences. An example would be a large kitchen hood back drafting and natural draft water heater. Unfortunately, most residential and commercial systems are not commissioned because it is not required. After all, once the equipment is hooked up it is supposed to work…. Right?
There Are Three Types Of Commissioning:
Initial commissioning: This occurs during the production of a new building or on a new HVAC system in an existing building
Retro commissioning: This is the first commissioning implement on existing HVAC equipment in an existing building.
Re-commissioning: This is commissioning HVAC systems that were already commissioned the first time but the owner wants to verify the system is still operating per design and manufacturer’s specifications
Services
ACCA Standard 5 and ACCA Standard 9 should be followed to ensure the system is installed per the design and are in compliance with ANSI/ACCA 5 QI HVAC Quality Installation Specifications.
Listed below are some of the services provided for residential and commercial gas fired furnaces, geothermal heating and cooling systems, air conditioners and air source heat pumps.
Verify air flow through the indoor unit is within acceptable CFM ranges per design and manufacturer’s specifications.
Verify total external static pressure (TESP) is within OEM specified acceptable range.
Verify the HVAC system has the correct refrigerant charge.
Ensure the system has the correct firing rate per the manufacturer’s name plate. Verification through measuring and adjusting fuel gas pressure, analyzing temperature split and performing a combustion analysis.
Determine whether or not room airflows meet the design application requirements.
Measure and verify room pressures do not exceed + or – 3 pascals.
Verify building whole house ventilation and spot ventilation is operating per Code and design.
Combustion appliance zone testing for systems utilizing natural draft venting.
Documentation of all services performed.