Your Guide to Evaluating and Buying an HVAC Control System

HVAC control systems come in different types with different elements. You have traditional analog inputs, pneumatic systems, digital controls, building automation systems, DDC systems, BMS building management systems, controller logic, and more. It can be a lot to handle.

But HVAC control systems are still incredibly important. These systems allow facility managers to monitor and control heating, ventilation, and air conditioning units, ensuring that they are operating correctly, meeting set points, and providing optimal energy efficiency.

If your facility is large and complex, then you may need a more comprehensive management system with multiple controllers and logic sequences of operations. On the other hand, if your needs are more straightforward, then you might be able to get by with simpler analog inputs and outputs.

So how do you evaluate an HVAC control system? Here are some factors to consider:

6 Key Pieces of Buying Criteria for Your Ideal HVAC Controller

When it comes to evaluating and buying an HVAC control system for business and government facilities, there are several factors you must understand to make the right choice. You must consider them to ensure you get a system that meets your specific needs.

This diagram illustrates how smart controllers facilitate lead/lag cooling. If the lead HVAC unit cannot sufficiently cool the space in 5 minutes, the lag HVAC is activated to help until the target temperature is achieved.

These 6 factors have consistently been present in my work with my clients at DPS. Aside from RTUs and central master stations, HVAC controllers are one of the most common device types we manufacture.

Let's go through these general buying criteria to keep in mind when shopping for any HVAC controller:

• Compatibility: The HVAC control system you choose should be compatible with your existing heating, ventilation, and air conditioning (HVAC) systems. This includes considering the type of HVAC systems you have (ex. pneumatic systems or digital controls) - and also ensuring that the control system you choose can communicate with them.
• Energy Efficiency: One of the primary benefits of an HVAC control system is its ability to improve energy efficiency. As such, it's important to consider the energy efficiency features of the system you choose. This includes the ability to set specific set points, monitor energy usage, and adjust HVAC performance based on occupancy levels.
• Sequences of Operations: The control system you choose should be capable of implementing complex sequences of operations to ensure that your HVAC system is operating at maximum efficiency. This includes the ability to automatically adjust settings based on time of day, occupancy, or outdoor temperature.
• Analog Inputs and Outputs: Depending on your specific needs, you may require a control system that supports analog inputs and outputs. Analog inputs allow you to monitor environmental factors such as temperature, humidity, and airflow, while analog outputs allow you to adjust settings based on those factors.
• Management System Integration: Many businesses and government facilities use building automation systems (BAS) or building management systems (BMS) to manage their HVAC and other systems. If you use a management system, you'll want to ensure that the HVAC control system you choose can integrate with it.
• Controller Logic: The controller logic of your HVAC control system is what allows it to interpret and respond to data from sensors and other inputs. As such, it's important to choose a system with advanced controller logic that can handle complex operations and respond quickly to changing conditions.

When you understand and utilize the above buying criteria, you can ensure that you choose an HVAC control system that meets your needs and improves the energy efficiency of your facility.

My original design for an HVAC Controller Expansion was rack-mounted, but one of my clients preferred the same wall-mount design from the standalone HVAC Controller. You can choose either mounting style.

Featured Control System: HVAC Controller from DPS Telecom

One option you have for your short list of HVAC control systems is the HVAC (Lead-Lag) Controller manufactured by DPS Telecom.

This controller can monitor and control up to six HVAC units for lead/lag operation and supports multi-zone buildings

It also comes with a convenient front-panel LCD touchscreen that enables technicians to run tests on each unit, configure controls and alarms, and see the status of all HVACs.

The lead-lag HVAC Controller from DPS mounts on the wall of your facility and has an integrated touchscreen.

With regard to hardware I/O, the controller provides 12 general-purpose discrete inputs and 12 additional relay outputs.

The Lead-Lag Controller manufactured by DPS Telecom offers an effective solution for managing up to six HVAC units for optimal energy efficiency, cost savings, and maximum equipment life. You also get D-Wire support for dozens of daisy-chained sensors, making it a convenient and economical option for facility managers.

Let's now take a look at the time savings you can gain from D-Wire or any similar bus-powered and daisy-chainable sensors for use in remote facilities.

Daisy-chained sensors will save you a ton of install and configuration time

D-Wire sensors are a crucial component of the DPS Telecom HVAC control system. These sensors allow facility managers to track the environmentals (ex. temperature, humidity) of their telecom shelter using convenient daisy-chained sensors.

With D-Wire sensors, managers do not have to worry about analog capacity on their HVAC controller or a tangled mess of "home runned" wires. The sensors use simple RJ12 connectors, which enable daisy-chaining dozens of sensors to a single DPS HVAC controller's D-Wire ports.

You can run the sensor chain for hundreds of feet, monitoring the equipment's temperature and airflow output of each vent and multiple ambient room temperature and humidity sensors.

Choose a device that matches your available site power

When you buy a HVAC control system, it needs power to work. Popular options are -48 VDC, +24 VDC, or 110/220 VAC.

By matching your device to your available site power (or using an AC wall transformer as needed), you'll avoid the need for additional installations or the need to return a purchase for something else.

This is why, at DPS, we commonly manufacture our devices in -48 VDC, +24 VDC, and +12 VDC build options. Some wide-range power inputs can even span two of those nominal voltages to give you flexibility.

DPS Telecom can help you with your HVAC control and remote monitoring project

As you can probably guess, I do this kind of thing a lot. Remote monitoring and control devices are the only thing we do at DPS. Over a span of nearly 40 years, we've learned most of the ways you can go wrong.

I encourage you to use this article, and the rest of the DPS website, in your search for your ideal HVAC control system. Depending on your needs, you may or may not need our HVAC Controller. It was designed originally for remote telecom huts, but the concept of cooling an enclosed space is fairly universal.

To speak with me or another DPS engineer about your project, just give us a call. Call 1-800-693-0351 or email sales@dpstele.com to get started now.

Andrew Erickson

Andrew Erickson is an Application Engineer at DPS Telecom, a manufacturer of semi-custom remote alarm monitoring systems based in Fresno, California. Andrew brings more than 17 years of experience building site monitoring solutions, developing intuitive user interfaces and documentation, and opt...