RIB® Trifecta and Rooftop Units

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Did you know the first air conditioner was built in 1902 by a guy named Willis Carrier? Air conditioning has come a long way since those days. Most buildings are conditioned by Rooftop Units, most commonly called RTU’s. Some are more complicated than others, often controlling humidity or air quality along with heating and cooling the building. No matter the complexity, they all provide a similar function, to keep the building comfortable.

In most RTU’s you’ll find a fan, to pull air from the building, and heating & cooling coils to condition the air before that same fan pushes the air back down into the building. At the heart of all this equipment, is the control system.  The control system is taking readings from sensors, and telling the equipment how to react to create a comfortable environment for the occupants.

Functional Devices’ Trifecta is the perfect set of accessory components to include in your RTU applications to power the control system, enable equipment, and verify operation.

The power supply, as the name suggests, supplies power to the control system. The controller and all the accessories use 24 volts AC. The power supply reduces the voltage from 120vac to 24vac, but it also has a few extras to make life easier for the installers and technicians that work on the equipment. For example, a PSH75A will have a breaker to protect the transformer in the event of an overload. It also has terminal strips for the wiring to land on, and it even has a 120 vac receptacle for a service technician to plug his laptop into, in case he needs to make adjustments to the control system.

Relays are used to switch equipment on and off from the control system. You’ll find a relay enabling fan contactors, stages of heating or cooling, and sometimes commanding dampers open or closed. You can even mount the NEMA 4 rated RIB2401C-N4 to the outside of a control cabinet so you can see the LED indicator without opening any of the panels, which makes troubleshooting a faulty unit easier.

RIB2401C N4

When the command for the fan is sent, the controller will often look for a status before moving on to enabling heating or cooling stages. The RIBXKTF is a cost effective current switch that can be installed on one of the current carrying conductors of the fan, watching for current flow. Once current is detected, we know that the fan is running so the controller can enable heating or cooling.

Just a few examples of how our most popular categories of devices can assist in controlling things we see and use every day. With Functional Devices, Inc’s commitment to quality, we know those devices are going to remain in control for a long time to come. I for one, dread the thought of returning to those days before Carrier had that great idea in 1902.

Ryan Smith
Ryan Smith
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