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  • Alex Mathers

Top 10 Commissioning Issues Found

The Top Ten List was a regular segment of the Late Show with David Letterman and were a comedic institution, renowned for their wit, irreverence, and satirical take on current events, pop culture, and everyday life. I remember staying up late to watch Letterman and enjoying the rapid-fire succession of humorous observations and visual gags. Whether lampooning political figures, dissecting societal trends, or poking fun at mundane topics, the Top Ten Lists showcased Letterman's unique brand of humor and his ability to find the absurd in the mundane. With their iconic countdown format and deadpan delivery, these lists became a beloved segment of late-night television.

I am not Letterman nor can I write a funny joke about commissioning (It’s not just good, it’s good enough!) but our firm has been actively involved in commissioning and re-commissioning hundreds of projects, thousands of pieces of equipment and systems of all different sizes in a multitude of facility ages and types. We have seen a wide variety of issues that range from minor (construction debris left behind) to expected (equipment left in manual after startup and programming instead of auto) to significant (valves piped backwards, overridden safeties, air-locked hydronic systems). From the thousands of issues we have identified and fixed here are the most common.

So - in the spirit of late-night TV – ladies and gentlemen, here is tonight’s top 10 list of commissioning equipment issues found:


Number 10 - Labeling


What should be easy, simple and straightforward can turn into a time-consuming activity. Complete and accurate equipment labeling is very important for the operations and maintenance staff. The equipment labels listed on the drawings and sequences of operation should match the field labels. These are verified as part of the commissioning process. However, it is rare that accurate, permanent equipment labels are applied at the time of testing - if at all.


There are a number of reasons for this including placard lead times, late changes to equipment schedules, and installation delays. However, if well planned, labeling can be done right the first time.


Why did the label refuse to stick to the equipment?

Because it said, "I'm not sticking around for this job, it's just too adhesive!"


Number 9 - Factory Controls and Integration


Units like packaged AC units, VRF systems or HHW boilers are controlled internally by factory mounted controllers with custom programming but do not always communicate and integrate well with the BMS. Sometimes these systems have not been set up properly to communicate with the BMS and documentation is not clear on troubleshooting issues. What also does not help is lack of support from installers of these types of equipment after initial start-up.


Compatibility issues can be a significant roadblock to proper operation. Different manufacturers may use different protocols and standards. Traditional BMS systems are often built on proprietary technologies, making it difficult to integrate third-party devices or components from different manufacturers.  Complicating this fact is when the sequence of operation written by the engineer of record requires operations that the factory controls cannot execute.


This topic can be a whole blog in itself – but in short – controls integration continues to be a major issue in the commissioning and operation of a facility.


What did the BMS say to the Package Unit? I got this funny control integrations joke and I would appreciate your feedback.


Number 8 - Contractor supplied reports and documentation is pencil whipped.


Field supplied documentation is not always incorrect, but there is a reason we review all documentation provided to us. Often the mundane task of documentation is pushed down to a junior level employee who may be quick to put down incorrect or incomplete information to ‘get the job done faster.’ When the documentation is sent up the chain there is no QC.  What is commonly sent to the CxA is assumed to be correct – but frequently we find clear mistakes, obvious pencil whipping, and even completely blank forms titled “Final Startup Report”.


Wanna hear a joke about a broken pencil?

Never mind, it's pointless.


Number 7 - Schedule Compression

While not an equipment issue, schedule compression is the biggest commissioning management challenge.

Every project has scheduling issues.  Some stem from long lead times, scope changes, and over confidence in timelines.

Compressed schedules at the end of construction causing contractor overlap is by far the biggest issue we have had to deal with when managing the commissioning process.

Schedule compression often leads to mistakes, quality problems, and rework. It can cause custom testing methods to have to be developed on the fly due to out-of-sequence activities.  If occupants move in, it can result in overtime second and third shift work.

The first 90% of a project takes 90% of the time. The last 10% takes the other 90%.


Number 6 - Under-qualified or absent personnel from installing contractor supporting FPT execution.

While also not an equipment specific issue, demonstration is a big part of commissioning.  While technical commissioning provides hands on functional testing by an SME that knows how to operate a system, all testing should be performed with the installing contractor present. While it is important that we have technical knowledge of all systems we commission, we are not always aware of unique operational differences in specific applications. The installing contractor, vendor and supplier must demonstrate to us, as representatives and witnesses of the owner, that the systems work as intended.

At the end of construction, during functional testing, budgets are strained, schedules are pushed (see #4) and subcontractors are on the next job (or frantically still trying to finish this one).  While specification and commissioning plans specify that knowledgeable personnel are present during testing, it is not rare to see a 1 to 2 year technician show up from the sub-contractors office.    

Did you hear the amazing story about the blind construction worker?

He picked up a hammer and saw.


Number 5 - Lighting Controls


Complex lighting control systems can optimize energy usage in a commercial building. With advanced control technologies, such as occupancy and daylight sensors and programmable schedules and overrides, lighting control testing has become more involved.


Rolling two common lighting controls issues into one - issues include lighting occupancy controls that do not deactivate lighting at the proper time (sometimes 30 seconds, sometimes 30 minutes) and daylighting controls that are improperly calibrated and over-illuminate the spaces that they serve.


How many Commissioning Agents does it take to change a lightbulb? Two; one to hold the ladder and one to hold the bulb in the socket while expecting the whole world to revolve around them.


Number 4 - Mechanical Sequences of Operation


The sequence of operation is one of the most important aspects of control.  Not only does it communicate the intended operation of the equipment, but it also lays out the sequential operation of equipment in different modes.  However, improperly applied, mechanical equipment sequences of operation can create conflict between systems or could be unclear to installers and controls contractors. At times, sequences are unclear or missing entirely from the design documents and are left up to the controls contractor to fill the gap or create.


Overly complex control sequences can be difficult to implement and troubleshoot – especially if it is for integrated equipment (see #2). A result may be operators manually overriding operating set points and sequences to keep equipment running.


Most controls engineers can’t sing but they do Rockwell



Number 3 - Mechanical, Plumbing and Electrical equipment on emergency and standby power


An IST is not just an electrical test.  While the blackout test does functionally test the Emergency Power Supply System (EPSS) including generator, ATS, switchgear, uninterruptible power supplies (UPS), and EPSS distribution and e-power receptacles, it is not solely, or even mainly, an electrical test. 


As written in a recent Blog, most issues found are mechanical related. Spring return dampers close, sometime tripping off AHUs as they come back online, BMS field controllers lose memory, sometimes wiping out all stored flow coefficients, equipment such as humidifiers, fan coils and exhaust fans don’t come back online (or were never put on standby even though drawings were clear).


People are usually shocked when they find out I'm not a good electrician.


Number 2 - Setpoints, schedules and alarms are either missing or programmed incorrectly.


Surprisingly, HVAC airflow setpoints are regularly found to not match design. This should be straightforward as these are clearly listed in the mechanical schedules sections. However, for reasons that escape many a commissioning agent, during the review of programmed setpoints, many can be found to differ significantly from design.


Not surprising, unless asked prior to programming, space temperature setpoints, operating schedules and alarm values are either just assumed or copied from other projects with no questions. Even if these are provided to controls contractors, it may feel like pulling teeth to get them implemented correctly.


This test must be endothermic, because it sure did take a lot of energy.


Number 1 - Installation does not match details from the design

Again, I the spirit of Letterman’s Top Ten, the #1 entry is usually seen as the least funny (or interesting in this case). As mundane as it sounds, we see it frequently.  From reheat coils, to pumps, to package units and fan coils installing contractors don’t always consult the details as much as their last project when mounting and connecting equipment.

Why don't construction installations always match the details?

Because sometimes they just can't seem to "measure up" to the engineer's lofty expectations!

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