Your questions answered: What are the benefits of HVAC fault detection, plus how to specify it

On May 7, Consulting Specifying Engineer and Schneider Electric presented a webcast that provided an overview of HVAC fault detection and diagnostics (FDD), how they are used and considerations for design and specifications. Additional questions covered some key topics.

By Consulting-Specifying Engineer May 28, 2024
Courtesy: Brett Sayles, CFE Media and Technology

Within commercial buildings, it is estimated that poorly maintained, degraded or improperly controlled equipment wastes an estimated 15% to 30% of the energy used and impacts operational costs and equipment life span. Smart technology enables the next generation of proactive and preventive maintenance through analytic tools such as heating, ventilation and air conditioning (HVAC) fault detection and diagnostics (FDD).

Not limited to energy savings, FDD technologies can also prevent energy performance degradation over time, support various commissioning processes, improve operational efficiencies and facilitate predictive maintenance, which contributes to increased equipment life, improved reliability and lower labor cost.

HVAC FDD is an integral part of any building design, and the eventual measurement and verification of its systems. With smart controls and an open architecture, FDD can be deployed for both new and existing building systems.

During a webcast on May 7, presenters from Schneider Electric provided information on the following learning objectives:

  • Identify major market trends driving building customers’ need for performance-based analytic solutions.

  • Correctly define the concept of heating, ventilation and air conditioning (HVAC) fault detection and diagnostics (FDD).

  • Gain the ability to name the outcomes, solutions and benefits of HVAC FDD.

  • Identify the functionality, reporting and results available for mechanical engineers or commissioning providers to offer building clients.

  • Obtain the ability to describe the key components needed to specify FDD.

Additional questions were answered by:

  • Jeremiah Cope, consultant solution architect, Schneider Electric

  • Shannon Kell, director, offer management-services for digital buildings, Schneider Electric

Have you received feedback that “speed” in repairing HVAC issues is a big priority in the industry?

Answer: Yes, we have seen industry studies and surveys that reflect speed in repairing HVAC issues is a top priority for them. We use FDs and analytics to ensure we find the issues prior to rolling a truck/ When we are on-site, we know the issue, likely know the root cause and can focus on repair and resolution.

Should HVAC fault detection be included with the BMS system as part of the base building offer?

Answer: This is an interesting topic. There are many different versions of HVAC fault detection analytics out on the market. For solutions that are one time only purchased or set up, it is recommended to provide the required software, hardware and fault detection rules as part of the base BMS solution (in either Div. 23923 or Div. 250010). For solutions that are subscription based, it is recommended to provide the setup (typically software and fault detection rules) configured as part of base BMS and the subscription paid for during or after the warranty service and/or with an ongoing maintenance and service contract. For solutions that are added later on, we recommend the BMS system include (not just capable) “systematic point tagging” to allow ease of configuration (i.e., time savings) once an HVAC fault detection is selected and added to the existing system. Or adopt ASHRAE’s guideline 36 standard that includes 15 defined HVAC faults as part of the BMS programming.

Is early proactive detection of HVAC issues a priority in lieu of waiting for an alarm from the BMS?

Answer: Yes, in most cases. I do believe that there are different, yet appropriate maintenance strategies for different equipment. Some equipment justifies a reactive replacement strategy. If it is cheap with a short life expectancy, like a stat, this strategy is perfect. For other assets, preventive maintenance (time-based, OEM recommended, traditional) may be OK. Condition-based, which moves from traditional preventive maintenance to performing maintenance based on what is happening within the system, requires FDDs and analytics. Proactive maintenance strategies take it one step further and use other tools to identify root-cause. They intervene prior to a potentially catastrophic event. In general, I do believe that data should drive decision making and maintenance strategy, but I also think that the type of asset, its age, criticality, redundancy and performance also play a role.

I hope you’re going to address/mention ASHRAE Guideline 36 sequences, which include some basic FDD sequences.

Answer: At Schneider, we have developed standard applications that align with ASHRAE Guideline 36 for our sequence of operations and design, including 15 faults. In addition, many of our FDDs align with the same points that the apps rely on.

Who initially sets up faults? Are there limits to what faults can be detected?

Answer: We have an onboarding team that takes data from the customer sites and sets up the systems. We have a list of FDDs and required points, so we can show which FDDs can be set up and if there are others that are critical. Then, mapping missing points into the system is a requirement.

Are most controls contractors providing FDD services, or is it likely that we would need to hire an additional party to do this?

Answer: Some contractors have proprietary systems. There are also technology service providers that play in the space.

Is this system replacing the Trane, Honeywell, Johnson Controls DDC system?

Answer: No, this is a web-based platform and is BMS-agnostic. It receives data from the BMS and does not replace the BMS.

On these examples, where were the energy savings found?  One big problem or lots of littles?

Answer: It really depends. On a large site, we can receive data on thousands of assets. You’ll likely always see a combination of energy savings opportunities over the course of a year.

Can you speak on the impact of FDD on the operations and maintenance staff’s normal operations/normal building controls sequences that they are used to? How much will their sequences change/create a need to learn new things? I’m concerned about the impact to our customers on military installations (public works maintains and operates everything, including adjustments to DDC sequences, etc.).

Answer: We can modify our diagnostics to meet their sequences and disable diagnostics for changes they do not want to do.

Are Schneider controls themselves capable of meeting G36 without purchase of Schneider FDD service?

Answer: We have standard applications designed to meet ASHRAE Guideline 36, and we use them on our projects. Issues exist in every system, so the FDDs and analytics are used to find problems and fix them.

Is there a minimum size of system to install this on?

Answer: No. However, we strongly recommend using it on large sites or where there is a significant distance to service the customer. The ability to remotely troubleshoot and resolve issues is a major benefit to labor challenges.

What is the cost added, such as percent added to the BAS price, to implement this?

Answer: At Schneider, we offer digital-first service agreements where use of this technology is core to how we execute BMS service agreements.