When Controls Systems Misbehave –- When to Replace an HVAC Controls System

As controls systems age, they can start misbehaving. Because controls systems rely on computer software as well as electronic hardware, they are subject to glitches and performance problems for a whole host of reasons. Sometimes a simple upgrade can resolve issues, other times these glitches are symptoms of bigger problems and an overhaul is your best bet.

Avoid the Frustration – Keep Controls Current!

When you start seeing the symptoms below, it is a good time to look at replacement, or at least a signficant upgrade:

  • Computer system upgrades conflicting with existing HVAC controls software. Some older HVAC software will not run correctly on new computers for a myriad of reasons – incompatible operating system or Java version, missing drivers, incompatible internet browser, etc. These conflicts get worse as the age gap between the HVAC software and the computer grows. And it’s not just one computer you need to consider. Any computer that wishes to view or access the controls system whether on- or off-site, management, maintenance dept. or service contractor may begin to have issues as the age gap grows. Like any computer software, upgrades for both software and hardware are necessary to ensure continued compatibility.
  • Obsolete repair parts. As manufacturers move on to the new more powerful controls systems, the older systems get left behind and are not supported. It becomes increasingly difficult to get replacement parts the older a system gets.
  • Obsolete communications or connectivity technology. Many older controls systems do not have a user-interface and require special devices to communicate with a laptop. Older systems often use serial cables or PCM-CIA Cards, technologies which are no longer available in new laptops. Often external devices or adapters don’t work, leaving field techs blind when they try to troubleshoot or program an older system.
  • Difficulty integrating new controls onto old controls systems. Though advances have been made to better integrate newer systems with each other (even if they are different manufacturers), older systems often have proprietary systems or older technology that doesn’t communicate with newer devices, even from the same manufacturer. If you are adding new HVAC equipment to your old controls system, you may have problems making everybody play nice together. It’s like trying to play a new CD in an 8-track player.
  • Limitations on control system functions like trending or load-shedding. Newer systems include improvements and refinements over the old. You may find your old dog system can’t learn new tricks. This might cost you much-needed efficiencies.
  • Un-maintained controls or controls operated by un-trained staff. Though not really an age issue, this is probably one of the single biggest issues in controls today. Controls are incredibly powerful in the hands of those who know how to use them, but can actually work against those who aren’t well trained. Newer systems tend to be more user-friendly. Think of old DOS-based systems vs. Windows®.

Generally we recommend keeping an existing controls system in place as long as it is effectively performing. A well-maintained controls system can last anywhere from 10-20 years, depending on the type of system and its capacity. But the key is to weigh the cost of an inefficient or difficult to service system against the cost of replacing it altogether. Controls are extremely powerful tools that will quickly pay for themselves and provide years of energy savings. But when controls misbehave they can cost you serious bucks. But when you start seeing serious issues cropping up, it’s time to bite the bullet and plan for your new controls system. Waiting to take action can be costly.