Top 3 Points to Consider Before Scheduling a Balance

  • HVAC equipment is installed and operational.

This one seems like a no-brainer, but there are always occurrences when Melink arrives to perform a balance and necessary equipment either hasn’t been installed or isn’t properly operational. Examples might include VAV’s or dampers that haven’t been installed, or a RTU that isn’t operational.

Ensuring that all ductwork has been completed, balancing dampers are properly installed, any grilles, registers and diffusers are installed, and the RTUs have clean filters helps make sure that Melink can provide a proper air balance, as well as mitigate any potential return service costs. Making sure that all equipment (especially RTUs) has undergone a proper start-up to confirm power should always be completed ahead of Melink’s arrival.

  • All HVAC equipment can be easily accessed.

Another hindrance to any proper test & balance is not being able to access the necessary equipment. This includes equipment installed inside the building, as well as equipment on the roof. When working with a customer located inside a mall or shopping center, security and approved roof access becomes another added component that must be considered.

Melink typically requires assured access to all applicable HVAC system equipment, including RTUs, VAVs, Exhaust Fans, dampers, etc. Access to fully open dampers, ceiling-height diffusers, and thermostats that may be in an office is necessary to properly complete the balance. Our Account Coordinators will also discuss roof access, security measures, and accessibility to ladders or lifts.

  • Allotting adequate time (2-3 weeks) to schedule and complete the balance.

Though some seasons are busier (or slower) than others, our goal at Melink is to provide every customer the same level of service excellence no matter the time of year. This includes communication with the customer, scheduling the site visit with one of our National Network technicians, performing the balance and working with the customer on any punch-list items, and finally, providing a certified test & balance report.

Our team of National Account representatives and technicians work with the customer through each step of the process. Scheduling service with Melink approximately 2-3 weeks out from turnover will help to ensure a proper and complete balance, and enough time to work through any punch-list items or lingering comfort issues for the customer.

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A Balancing Act: Air Balance is an important part of HVAC maintenance

When it comes to HVAC, no news is good news for restaurant facility managers. When you start hearing chatter about the building being hot and humid, drafty, smoky or uncomfortable, you know a problem has already taken root. It’s a lot like a piano being out of tune. In addition to unhappy customers and employees, these comfort issues typically are indicators of energy inefficiency within a system. So, what can facility managers do to prevent comfort and energy threats?

Identifying Common Problems

“Facility managers need to be trained on air balance and push it to their service contractors,” recommends Jeff Dover, resource manager at RFMA.

A good place to start is to gain a foundational understanding of building pressure and common HVAC deficiencies along with following seven easy steps to bring your restaurant back into tune. Most importantly, learn how to look for negative building pressure. Remember, the goal is to stay slightly positive in building pressure.

There are three methods to identify negative building pressure. The first and most reactive method is to monitor signals that your building is negative. These signs are hot/cold spots, entry doors that are hard to open, poor smoke capture, humidity, condensation dripping from diffusers and drafts.

Second, you can measure the building pressure yourself or with the help of your service contractor by using a pressure reading tool such as an anemometer to get a ballpark pressure reading. The third and most accurate method is to hire an air balance firm to check the facility’s building balance once a year. If comfort-related issues or a negative building pressure reading are observed, then an air balance needs to be scheduled.

Investigating the Cause

What causes a building to become negative or unbalanced? The usual offenders are equipment deficiencies, improper preventative maintenance programs, and adjustment errors such as kitchen staff fiddling with thermostats or service contractors opening or closing dampers.

 Here are 10 example deficiencies you or your service contractors should be on the lookout for:

  1. Exhaust fans in poor condition
  1. Supply air leaking above ceiling
  1. OA dampers improperly installed
  1. Exhaust fans not sealed to curb or hinged correctly
  1. Dirty compartment/coil in the RTU
  1. Tops of diffuser not insulated
  1. Filters improperly sized for hoods
  1. MUA not operating properly
  1. Dirty indoor/outdoor filters
  1. Worn/broken belts

7 Steps to HVAC Balance

Once you’re ready to bring a facility back into tune, there are seven easy steps to complete. These steps may be completed by the facility manager alone, but are more likely in partnership with a service contractor. To get started, pull out the facility’s previous balance report to use as a base line for data.

One Principal Engineer at a hamburger fast food chain overseeing thousands of locations explains how her team uses the air balance report to get started with troubleshooting comfort issues.

“The reports really are my first line of defense when someone says ‘Hey, my store is cold/hot/humid,’ ” she points out. “The first thing I do is pull out the T&B report and see what it says. I look at the punch list and ask was anything wrong? Not fixed? It helps when I have to remotely assess or diagnose problems.”

Whether the previous air balance report has been reviewed or not, proceed to the following steps:

  1. Ask the onsite restaurant managers what the complaints are from employees and customers.
  1. Turn on all HVAC equipment.
    • Verify thermostats are set to “FAN ON”
  1. Check building pressure with the flame test in different areas around the restaurant (Figure 3)
  1. Observe smoke capture
    • Is the hood in the correct overhang position?
    • Are there drafts along the cook line?
  1. Check for common comfort issues (hot/cold spots, entry doors that are hard to open, poor smoke capture, humidity, condensation dripping from diffusers and drafts).
  1. Inspect the equipment.
    • Are the filters clean?
    • Are the belts in good condition?
    • Are the exhaust fan wheels clean?
  1. Determine an intervention plan.
    • If some preventative maintenance actions and/or repairs need to happen, start with the service contractor.
    • If equipment is inoperable, have it repaired or replaced.
    1. If the preventative maintenance actions are in order and the problems persist, call in a certified air balance company that has experience with restaurants like yours.
Facility managers need to trust that their service contractors will notify them of airflow-related issues. Those technicians are out on the roofs and looking at the HVAC system components more than anyone else. If the restaurant has negative pressure or other out-of-tune symptoms, the service contractor needs to inform the facility manager right away. After all, you want your customers and employees to continue singing your praises. 

What to know about choosing an air balance contractor

Due to the skill level required and equipment needed, facility managers and mechanical contractors hire professional test and balance contractors to bring buildings into balance at the end of construction, remodels, rebalances for existing buildings and equipment changes. When HVAC equipment is installed and started up, it may not function according to design specification and eventually will delineate from proper operation if not corrected. 

Facility managers and mechanical contractors also bring in TAB contractors to investigate HVAC comfort problems. Are you aware that most HVAC problems stem from poorly maintained HVAC equipment or performance assumptions?

Selecting a balancing firm can be tricky business, but it doesn’t need to be. Following are criteria for choosing a balancing contractor, based on our experience during the past 30 years. We hope our perspective will serve you.

  • Use a certified firm
  • There are two main certification organizations:
  • Look for thoroughness. Like any service, you want to be sure your vendor is concerned about the details.
  • Look for integrity. Since most of the value of an air balance is invisible, you need a vendor you can trust.
  • Experience with your industry. HVAC systems differ among restaurants, retail stores, hotels and hospitals. Make sure your balancing partner is familiar with your type of facility needs.
  • Maintain objectivity. Have a third party firm balance your HVAC system to prevent shortcuts and misreporting.
  • Hire directly. Avoid conflicts of interest by hiring the balance partner yourself.
 Air balance report necessities
  1. Air flow measurements and adjustments
  2. Punch list with images
  • Punch list items refer to discrepancies with the design prints. For example, the prints might show there is a diffuser in the rest room, but the facility does not have it.
  • HVAC equipment data
    • Make, model, serial number, fan/motor data, voltage, belt size, equipment condition, amperage, pulley size, etc.
  • Building pressurization
    • Reading of the balanced building pressure

The above list includes the basic deliverables you should expect from an air balance report. You can read our article  How to read a Melink Test & Balance Report for a visual example of an air balance report.

To prepare for the service, a balancing firm will request the design prints of the facility and inspect any previous balance reports. In many cases with existing buildings, prints and reports are unavailable. If that happens, the air balance technician will have to work from best practice measurements. This is one of many situations where having an experienced and certified balancer is an asset because of the knowledge required to do this well.

Once onsite, the balance technician will briefly talk to your management staff and ask about any HVAC-related issues they are experiencing. A common complaint of restaurant facilities is a hot kitchen, which can be indicative of a rooftop unit with dirty blower wheels or filters, as well as loose belts on a failed compressor. These complaints give the balance technician an idea of where to begin.

Next, the balancer will spend time inspecting and measuring the equipment on the roof. He or she will record RPMs and amps, check exhaust fans and look for basic adjustments. Then the balancer will go back inside to check building pressure and take measurements of the airflow. All of this data will tell the technician what he or she needs to do. After more adjusting, such as dampers or RTU belt tightness, and measuring the effects, the technician will bring the HVAC ecosystem back to design standard.

At that point, pressures and measurements are then documented in a report. In the case of a Melink balance, the technician will also check thermostats and train staff on the proper settings, if requested by the manager. Findings will be explained to the manager as well. Finally, the facility manager or project manager will receive the report after it has gone through quality inspection.

ADDITIONAL READING:
Sources:
  • DuChane, Greg. “Optimizing Air Balance Report Data.” Trane Tracks (Apr.2015): n. pag. Trane. Web.
  • “NEBB.” International Certification, High Performance Building Systems. N.p., n.d. Web. Sept.1, 2015.
  • Prager, Ron. “Demystifying HVAC: Why Test and Balance?” (n.d.): n. pag. Web. Sept. 1, 2015. 

Troubleshooting Air Balance With Mechanical Contractors

Are you still experiencing HVAC comfort or efficiency problems?  It’s time for the next level of technical HVAC skill.  Though at this point you may have realized you’re dealing with negative building pressure, you might wait on calling the air balance contractor and first become more informed about the problem with your management team.  It’s time to call in your trusted mechanical contractor (MC).

Your contractor’s first steps will be to inspect many of the same areas we advised in our previous post. These areas should include circuit breakers, thermostats, as well as the areas listed below.  In addition, you should locate any past air balance reports and confirm that all the punch list items were corrected.  With these observations and baseline data as your starting point, you or your MC can begin to formulate a hypothesis. To dig deeper into problems, check the following areas where we most frequently find the causes of HVAC comfort issues:

1.   Filters inside the unit

Dirty, old, or clogged filters will restrict airflow through the unit.  Filters should be at least replaced quarterly for a commercial unit and can be added as part of a preventative maintenance scope of work.  In the Restaurant Facility Management Association’s Facilitator Magazine, Red Lobster Facility Manager Angela Hughes writes in her article Staying On Top of Comfort Concerns, “The washable metal filters inside each makeup air fan need to be cleaned during major preventative maintenance.  These are often overlooked by HVAC preventative maintenance vendors.  Dirty filters can block airflow into the unit and greatly affect the building balance.  If the filters are damaged or missing, be sure to replace them.”

Dirty air filters

Above: Dirty Outdoor Filters

 

2.  Inspect coils inside units

Dirty, clogged, or frozen coils can also heavily restrict airflow through the unit. Mechanical contractors are equipped to unfreeze and clean coils.  Angela Hughes explains, “Dirty coils will cause the unit to freeze up and temporarily shut down, which causes stress on the compressors.”  Further, if the rooftop unit (RTU) blower compartment and/or coils are dirty, then they are likely causing reduced airflow and contaminated air.  The solution is to clean internal components of the RTU.

Frozen evaporator coil
 

Above: Frozen Evaporator Coil

Dirty RTU blower compartment

Above: Dirty Rooftop Unit Blower Compartment
 

RTU dirty coil

Above: Dirty blower wheel inside Rooftop Unit

3.   Check refrigerant levels

Low refrigerant levels can lead to uncomfortably warm temperatures. Your mechanical contractor should be equipped to refill refrigerant.

 

4.   Open up units and inspect outside air dampers

The amount of outside air is specified in the building’s design, however it is often adjusted later as a quick-fix for short term issues, leading to bigger problems in the long run.  It is common to find improperly installed and inoperable outdoor air dampers, which negatively impact the building pressure.   The dampers will need to be adjusted to proper position and outside air intakes may also need to be installed to achieve desired airflow.

Improperly installed air dampers
 

Above: Improperly Installed Outside Air Dampers (sealed closed with caulk)

 

5.   Check for negative building pressure in your facility

The tell-tale sign of negative building pressure can be found with using the door test.  A quick way of checking your building’s air pressure is to test it with a lighter or a match at an exterior door.  Crack the door open and place a lighter in the crack as pictured below.  If the flame pulls toward the inside of building, then the building is negative.

Door lighter test

 

Above: If flame pulls toward inside of building, the building is negative.

 

6.  Has your facility undergone a remodel, renovation, or a major change in equipment?

Remodels, renovations, or major equipment replacements change the distribution of airflow and requires an air balance service.  HVAC equipment installed in a building will not function at design specification at start up.  Adjusting the system to design specification requires testing, adjusting, and balancing.

These are 6 examples of what your mechanical contractor may discover in their assessment process.  If they are able to find and properly resolve the HVAC comfort or efficiency issues, then your troubleshooting may end here.  If not, you may need to consider calling in a certified test and balancing firm.  See our next post in this series for understanding what to look for in a test & balance contractor.

Additional Reading:

  1. Bringing in an Air Balance Contractor, Larry Moore, Melink Test & Balance
  2. Angela Hughes, a Red Lobster Facilities Manager with distinguished technical knowledge of HVAC systems, authored a very practical approach for FMs to self-diagnose comfort problems without prematurely spending money on contractors. Staying On Top Of Comfort Concerns
  3. For suggestions on preparing for an air balance, read Optimizing Air Balance Report Data  by Greg DuChane, Retail-Restaurant Vertical Market Director at Trane
Resources:

DuChane, Greg. “Optimizing Air Balance Report Data.” Trane Tracks (Apr. 2015): n. pag. Trane. Web.

Hughes, Angela. “Staying On Top Of Comfort Concerns.” Facilitator Magazine Apr/May (2015): 66. Restaurant Facilities Management Association, 25 June 2015. Web. 26 Aug. 2015.

Melink Test & Balance Technicians. HVAC Deficiency Images. Digital image.Melink Test & Balance. Melink Corporation, n.d. Web. 26 Aug. 2015. .