Determining Compatibilities in Commercial HVAC Retrofits
Owners or managers of large commercial buildings are faced with a choice when their HVAC system’s efficiency and effectiveness dip: should they keep their system as it is, retrofit and upgrade it, or replace it entirely? For systems that are often designed to last decades, it can seem imprudent to try and keep up with the manufacturer’s latest updates. However, retrofitting systems which don’t require significant internal work can offer significant benefits, including reduced maintenance costs and increased system efficiency.
Case Study: HT-3000 Control and Display Upgrade for Dectron’s Dry-O-Tron
We wanted to give a concrete example of a simple, high-quality HVAC retrofit for this article. The HT-3000 controller is one of a number of commercial HVAC retrofits for Dectron’s Dry-O-Tron commercial dehumidification systems. It provides a complete replacement of the HT-800 controller with faster processors, increased connections to sensors and improved controls of ancillary features, including modulating heaters and refrigerant pressure transducers.
Benefits Over the HT-800
Compressor Protection: The HT-3000’s refrigerant pressure transducers monitor the system’s heat levels and alert facility staff when the refrigerant’s temperature dips above or below hazardous levels.
While this is inevitable, it can be a sign of problems if it is outside of nominal ranges for too long. If the temperature is too high and the system is not working efficiently, utility bills will skyrocket. Too low and there is the risk of compressor damage due to liquid floodback—saddling commercial building owners and managers with repair costs.
Alarm Codes vs. Panel Failures: To accurately diagnose an HVAC system issue, a technician needs to be familiar with the system’s potential faults and error codes. With the existing HT-800 controller, there was limited information regarding fault codes. The HT-3000 offers much more information to the end user and technician, with available inputs for the optional voltage monitor, Firestat, Freezestat and blower overload sensors. In each of these cases, a technician is more quickly able to isolate and fix any problems.
Increased Efficiency: The HT-3000 helps to maximize efficiency for Dry-O-Tron systems in two ways. The first is the control of modulating heaters that can increase the temperature of output air to match the settings of the thermostat. This allows the compressor to continue running, rather than cycling and increasing energy usage. The other is the refrigerant pressure transducers. By monitoring temperature conditions, the HT-3000 can minimize periods of superheat that damage the system’s overall efficiency.
Commercial building owners and managers should always consult with HVAC professionals before implementing any retrofits to their building’s HVAC systems. In the case of the HT-3000 retrofit, there are relatively few concerns about interoperability. For one, the system is designed and manufactured by Dectron. In addition, there are connections for all of the parts that would normally be connected to the obsolete HT-800 controller. Regardless of the manufacturer or upgrade type, there are two core questions that should be answered before moving forward with any retrofit project:
- Would a retrofit be more cost-effective and efficient than a total system replacement over time?
- Does the retrofit require significant changes to the system’s components, size, or weight?
Compatibilities in Other Commercial HVAC Retrofits
The HT-3000 is a nearly like-for-like replacement for the HT-800. This isn’t true of many commercial HVAC retrofits. It’s crucial for specifying engineers and HVAC contractors to understand not just the parts requirements for any upgrades, but also the costs versus ongoing savings. In many cases, the process is much more involved and involves comparing sensors, valves and many other factors. Considering that manufacturers rarely produce compatibility charts on their own, working with a distributor who is familiar with many different makers’ systems can make the process considerably less arduous.