Water Balancing of HVAC Systems
What Is a Water Balance?
A Test and Balance (T&B) is completed on an HVAC system to ensure the system is installed correctly and operating per the mechanical engineer’s design. In some mechanical designs, the unit will cool and/or heat the air through water coils. One reason water coils are used in a design is because they heat and/or cool the space more efficiently. Many times coils may have a higher upfront cost, but they provide a greater long-term energy savings. As air passes over the coils, the coil either absorbs the heat or extracts the heat to cool or heat the air. A water balance is performed to ensure the correct flow of water, measured in gallons per minute (GPM), is passing through the coils.
Why Is a Water Balance Important?
A proper water balance should be completed on HVAC equipment for many reasons. A primary reason is to prevent any potential comfort issues. If a chilled water coil does not have the correct flow, the coils will not absorb the heat from the air passing over them. Alternately, if a hot water coil does not have the correct flow, the coil will not extract enough heat the air. This can cause comfort issues in a space.
These systems are designed to have a certain flow through the unit, and if the flow is not correct, this can also cause damage to the equipment. To avoid or investigate these issues, a proper water balance should be completed by a certified firm. An NEBB-Certified firm, like Melink, has the experience to perform a water balance, ensuring your systems are operating as designed.
How Does a Melink Technician Perform Water Balancing?
Inspection of the Equipment
Using the latest set of mechanical, Electrical, and Plumbing (MEP) plans and the pump curve, the technician will:
- Verify the equipment is installed per design.
- Verify the equipment is operational.
— All pumps should be operating and in a solid state (meaning the balance scenario does not change during the balance).
- Verify the controls are complete.
— Permanent wiring should be complete.
- Verify the coils are clean.
— Dirty coils can prevent the system from properly heating or cooling the air.
- Obtain unit operating data.
Balancing the Equipment
This procedure will change based on the type of balancing valve.
- Place the unit into full heating or cooling.
- Purge sediment from the unit.
- Using the calibrated equipment, measure the water flow (GPM).
- Compare the measured flow with the design flow.
A final report will be distributed by Melink, containing design data, equipment data, test data, and photos.