Understanding Normally Closed Delay-on-Break TDRs for Air Conditioning Systems
Air conditioning is a cooling method that removes heat and reduces humidity in an enclosed area to create a comfortable environment. Air conditioners provide air treatment by transporting warm air outdoors and replacing it with cooler refrigerated air. Air conditioning systems come in a variety of designs, but the most common include central air conditioning, ductless mini-split systems, and window air conditioners. In addition to residential and commercial buildings, air conditioners are available in motor vehicles and aircraft, and portable units provide cooling in temporary locations such as construction projects. In this article we breakdown how to diagnose your air conditioner and make sure that your air conditioner relay is running properly.
How Do Air Conditioning Systems Work?
Heating, ventilation, and air condition systems (HVAC) incorporate air conditioning capabilities into a more extensive network of ductwork and ventilation systems. HVAC systems use ductwork to transport heat out of the building while simultaneously producing cold air in to replace it. Most A/C units work in this fashion:
- Grilles at the base of an A/C unit pull warm air into the machine, where it flows over chiller pipes filled with coolant.
- A dehumidifier reduces moisture in the air before a fan blows it back into the building.
- The refrigerant in the chiller pipes captures the heat from the recirculating air and carries it through a compressor and condensing pipes, which reduce the temperature of the coolant.
- An electric fan pushes residual heat safely outside to dissipate.
The Importance of Normally Closed Delays for Air Conditioning Systems
Air conditioner relays control the flow of electricity into an air conditioning system. Time-delay relays (TDRs) specify the amount of time before opening or closing the circuit to allow voltage to flow through the system. This delay allows the blower motor to continue operating after the compressor has been turned off by the thermostat. Blower motors direct cooled air from the HVAC system into the home or business via the ventilation system, helping to thoroughly circulate cooled air throughout the indoor space and ensure optimal temperature per thermostat settings.
With the use of a TDR, the blower leverages the residual cooling effect of the evaporator coil to produce additional chilled air while the compressor is off, thereby improving overall energy efficiency. TDRs also create a time delay to prevent excessive compressor cycling due to frequent thermostat adjustments, power interruptions, and vibrations. This increased control significantly reduces wear and tear on air conditioner components and decreases energy usage.
How to Test an Air Conditioner Relay
If an air conditioner relay is not working correctly, the compressor will not engage when the air conditioning system is on. The two critical relays in a standard A/C system are the capacitor relay and the starter.
- The capacitor provides power to the compressor, blower motor, and exhaust fan.
- The starter relay transmits power from the capacitor to the compressor.
If an A/C unit will not start but makes a humming noise, the capacitor is likely broken. Fortunately, the starter and capacitor relays are easy to examine and relatively inexpensive to replace.
High-Quality Time Delays for Air Conditioning Systems
Amperite manufactures relays, flashers, and timing controls for a variety of industries and applications. Our experienced engineers and specialists produce relays specifically for use in HVAC applications. We provide superior quality products with personalized service and timely distribution, so you can be sure that you have the products you need when you need them.