One very important function of any Roof Top HVAC unit (RTU) is to perform cooling whenever its needed no matter what the outside temperature is or what season it is.
This can be accomplished through the function of the economizer. Its very critical that the HVAC setup and verification be performed during unit function checks but it often gets overlooked. The economizer functions at ambient outside temperatures that allow cooler air to be brought in from outside rather than run mechanical cooling to perform the air conditioning task of the unit, and because mechanical cooling equals money spent on power, cool air is still free.
A properly functioning HVAC unit will save on energy costs.
The economizer is made up of several key components. A control module, damper motor, dampers, interconnecting linkages and temperature sensors. All these components work together to supply a constant air temperature when a call for cooling is needed. The economizer not only allows cool outside air into the space when calling for air conditioning but it also allows clean fresh air into the space during a call for heating or any function if the indoor supply fan. This maintains good air quality for the conditioned space being heated or cooled. As a general rule between 10-20% of the air being put through a RTU should be fresh air.
Cusp seasons (Spring and Fall) are generally when the economizer functions for cooling.
However, if you live in a climate such as we do in Calgary, weather and temperatures change and fluctuate all year long. It is possible to require cooling in the middle of winter so it becomes much more important that the economizer is functioning correctly; not only to save you money in energy consumption but to also protect the compressor from operating at low ambient temperatures which can cause damage to the compressor and possibly lead to large repair bills.
A few simple things to look for to ensure your HVAC economizer is being maintained correctly.
What I am going to point out won’t tell you if the economizer is functioning correctly but if someone isn’t taking the time to ensure these points are covered then they definitely aren’t taking the time to check the economizers functions. First take a look at your pre filter, is it there, is it damaged, is it clean? Second; is the filter access panel properly secured? Third; is the economizer hood properly secured, damaged, etc. If any of the issues are visible on your site look back in your service providers notes, if none of this is documented then chances are the economizer is not functioning correctly nor is it being maintained correctly.
If you require service on your HVAC equipment please feel free to contact our team of experts to assist you.
This checklist will help you maintain your HVAC system, keep your repair needs in check, and help your equipment last longer.