Commissioning Close Out

MSC was contacted by a commissioning agent whom we had worked with before to get involved with troubleshooting on an extensive project.

One of the items holding up commissioning close out was coil performance testing specifically chilled water coils that had difficulty making discharge air temperature on design days. The two units in question were 100% outside air units with upper and lower coils. There were several similarly sized units by the same manufacturer that were performing properly, and it appeared that the coils in the units in question were in good physical condition installed properly including the piping serving them.

We installed A Fuji strap-on ultrasonic flowmeter to the chilled water return line of air handler 4 and verified all other parameters. Proper airflow at 12,800 CFM, OA temperature of 93.4f, Chilled water temperature of 43.2f, and lastly a chilled water return flow that was slightly low. Testing water flow and increasing it by 28% gave us the results we were looking for to maintain the AHU discharge air temperature at full flow at ASHRAE OA design dry bulb wet bulb conditions. We also used a new Flir thermal video camera to help determine coil temperatures entering and leaving the coil by scanning every inch of the coils to make sure there were no temperature anomalies, dead or low flow spots.

Coil temperatures were consistently even throughout, and we had it recorded on video. It appeared that a simple typo on documentation provided to the balancer had shortchanged the chilled water flow slightly and that the proper water flow to achieve coil performance with proof was found. This allowed the commissioning agent to close out several systems and documents to call the job done. On to the next one. 

About MSC - The Go To Guys

We are a service sub-specialist in the technical intricacies of HVAC, process cooling, and building automation systems in commercial, industrial, and institutional environments. MSC is recognized as the leading industry expert in solving elusive problems and attaining peak performance from clients & mechanical equipment and overall systems.

Located in northern New Jersey, MSC is the only specialized contractor of our kind in the Northeast and Mid-Atlantic regions. We are MSCA STAR-qualified, NEBB-certified, fully-licensed in electrical, plumbing and HVAC, and our engineers and technicians are the most knowledgeable in our field.

MSC - Mechanical Service Corp.
41 South Jefferson Road
Whippany, NJ 07981
973-884-5000
http://www.mscnj.com