11 Tips for integrating VRF HVAC systems

Integrating VRF systems can be quite a task - even for professionals, when doing it for the first time. However, learning how VRF works and asking the “right” questions can save a lot of hassle during the integration.

Following, are some tips to get you started:

Tip #1 - UNDERSTAND HVAC SYSTEM COMPONENTS

VRF systems are made up of two different, but equally important, system components: indoor units, and one or more outdoor unit(s).

The outdoor unit will (among other things) dictate the operational states and modes, e.g. is the system on/off or set to heat/cool.

The indoor units will work to achieve the individual temperature setpoints for each room and manage the requested fan speeds

Tip #2 - CONTROL THE CONTROLLABLES

There are a number of functions that Home & Building Automation systems can control for each indoor unit. Many integrators could find these terms confusing.

To make sure you’re always clear as to what they mean, we’ve created a list of common controllable functions along with the functionality that they control:

  1. Operational State - Is the unit state on/off
  2. Operational Mode - Is the unit mode in Cool/Heat/Fan/Dry/Auto
  3. Temperature Setpoint - The temperature that the unit will attempt to reach
  4. Fan Speed - How fast the fan is spinning Hi/Medium/Low/Auto

Tip #3 - DON’T TRY TO CONTROL THE UNCONTROLLABLE

Don’t waste time attempting to create controls for the outdoor unit(s), focus on the indoor units, since they’re the only ones you’ll need to integrate into your system.

Tip #4 - CONTROL EACH INDOOR UNIT THROUGH ITS UNIQUE ADDRESS

When a VRF system is installed, the outdoor unit will automatically assign a unique system address for each indoor unit.

Before beginning your integration process, it’s important for you to first write down a list of all the indoor unit addresses along with the corresponding room where it is located. Having this done before starting an integration will make the process much faster and easier for you!

Tip #5 - SET EACH INDOOR UNIT FUNCTION INDEPENDENTLY

Unlike traditional HVAC systems, all VRF indoor unit functions are managed independently of one another. Most VRF indoor units are not affected by the state of any other unit in the system.

For example, the living room’s air conditioning operational state (on/off), temperature setpoint, and sometimes even operational modes (heat/ cool) will be managed independently of the kitchen and bedrooms.

So while you might be used to integrating functions on a systemwide level, you should be careful to make sure you integrate the functions for each unit separately.

Tip #6 - GROUP UNITS TO SIMPLIFY CONTROL

When two or more indoor VRF units are physically linked to work as a group, only the master unit (the unit with the lowest unique system address) can be controlled.

You shouldn’t add any of the slave units into the automation system since all of the slave units will ignore any other commands received.

Tip #7 - LOOK FOR UNIVERSAL SOLUTIONS

HVAC systems, on average, last between 10 and 15 years, while Home & Building Automation systems can in theory last forever since their value is found in the underlying Automation software, not the hardware interface device.

Understanding that HVAC systems will, more often than not, be replaced sooner than the Home & Building Automation systems, you should encourage your clients and/or HVAC installers to use universal solutions to integrate the HVAC with your Automation system.

Universal solutions will ensure that whenever the HVAC needs to be replaced, the new system can be easily re-integrated with your Home & Building Automation system.

Tip #8 - DO NOT CONFUSE “RETURN AIR TEMPERATURE” WITH “ROOM TEMPERATURE”

Usually, the VRF will measure the temperature through a sensor mounted inside the indoor unit. This is often mistakenly interpreted as the actual room temperature.

Since hot air rises, a sensor in a ceiling unit could sense a dramatically different temperature from what would be felt closer to the ground. The higher the ceiling, the larger the difference could be.

Tip #9 - BEWARE MALFUNCTION NOTIFICATIONS

Sometimes, after successfully completing an HVAC integration, the HVAC system will not respond to the commands given. Before you start tearing your hair out in frustration and restarting the entire integration process, first check and see if there is an error notification with the HVAC itself.

When an error occurs, the error code notification should appear on the HVAC’s wired remote, but many Home & Building Automation systems have the ability to display the error code on the main controller as well.

If your Home & Building Automation system doesn’t allow the errors to be forwarded, it would be a good idea to add in that functionality, as this information can be used by HVAC installers as well as your customers in order to quickly resolve any HVAC related issue

Tip #10 - NO DUAL SETPOINT FOR VRF SYSTEMS

Traditional HVAC systems (or more specifically, the Thermostats that control them) often use different setpoints for cooling and heating. Most VRF systems function a little differently, where there will usually, be a single setpoint used regardless of the operational mode.

This is important for you to remember so that you don’t waste time trying to set up multiple setpoints since all you’ll need is one.

Tip #11 - DON’T OVERCOMPLICATE HVAC INTEGRATIONS

Most Home & Building Automation integrators have had a bad experience trying to integrate a VRF HVAC system into their Home or Building Automation system. As a result, they feel as though the process of VRF integration is complex and burdensome.

The truth is that these integrations should be incredibly simple (often, just a 2 wire connection). Previous bad experiences are probably a result of trying to perform integrations with the wrong tools! But by using these tips and tricks, Heating and Air Conditioning integrations will become a breeze, regardless of the system type (VRF, Mini/Multi Split, Zone Control, etc…).

Bonus Tip - DON’T BE AFRAID TO ASK FOR HELP!

If you ever have any questions about HVAC integration, automation, or configuration, you can always reach out to one of our professionals by simply filling out the form located below.

Join Our Newsletter