Our HVAC equipment can’t run without the contactor coil, but contactors can develop problems with age and during high-voltage electrical events. Contact pitting is unmistakable, and it’s unfortunately all too common in areas where bugs can get into the coil and fry on the contacts. Factor in problems with the utility, such as brownouts and surges, and that’s a recipe for a failed contactor coil. However, it can be a hassle to keep OEM contactors on the truck and with long lead times when you don’t have them in stock.

Aftermarket products sometimes get a bad rap, but I’ve been working with the White-Rodgers SureSwitch lately, which I consider to be a viable alternative to OEM contactors. In this article, we are going to take a look at the SureSwitch as an upgrade/alternative to the standard OEM contactor. 

Long Lifespan & Contactor Protection

The SureSwitch is an electronic replacement for mechanical compressor contactors, and it has been designed to last 5 times longer than stock contactors. Its extra-long lifespan is achieved by some innovative design characteristics that I think are worth considering as an alternative to standard electromechanical contactors.

The first design feature to note is that the SureSwitch is sealed, making it impervious to ants, lizards, or any other nuisance pests that are likely to foul out standard contactors. 

The second consideration is that the unit has a multivolt coil that is applicable to common coil voltages: 24, 120, 208, and 240VAC. This feature reduces truck stock or the need to run to the supply house since all of those voltages can be handled by one contactor coil. 

The SureSwitch also has a unique switching mechanism. Unlike traditional electromechanical contactors that are susceptible to damage caused by arcing and heat, the SureSwitch uses what White Rodgers refers to as zero cross switching. 

Zero cross switching is achieved by utilizing a light sensor inside the relay that indicates arcing. A microprocessor then modifies the switch time to create a custom opening and closing pattern to protect from damage-causing arcs. 

Compressor Protection 

The SureSwitch also has some additional features that offer compressor protection. 

Via dip switches, the SureSwitch can be set to detect and protect the compressor from low-voltage situations caused by brownouts and short cycling.

Random Start Delay

The SureSwitch comes with a random start delay, which is helpful in circumstances where there may be potential current spikes caused by multiple systems coming on at the same time. This situation is quite common in multi-family units or light commercial applications when several units go down during a power outage and come back up all at once.

Test Button

The SureSwitch was also designed with an equipment test feature. Once the technician has the SureSwitch completely wired in, the test button can be depressed for 1 second and will initiate the compressor and condenser fan for 5 seconds. 

Wiring

The SureSwitch also has an intuitive wiring layout. The design characteristics are well thought out, and the fact that the connection points are labeled enables the technician to install the SureSwitch quickly and with confidence. From the crankcase heater to a hard start kit, there is a specific tab for most of the common components and accessories a technician would expect to see in the field. 

As you can see, it doesn’t get more user-friendly than the SureSwitch. The raised designations take the guesswork out of at least one portion of our job. I also found the included wiring diagram to be laid out very well. However, because I visualize things in color, I like to identify the wires I will be using on a particular job and outline them for reference.

Because the SureSwitch is capable of replacing so many different contactors, I think there will be some apprehension at first due to some of the stigmas surrounding universal parts. However, I found the installation process to be painless and straightforward. As you can see from the illustration below, the layout just makes sense. 

Conclusion

In areas where contactor failure is quite common, I like to keep a stock of SureSwitches on my truck. I can understand the wiring diagrams pretty easily and feel like I can do my customers a service beyond just replacing the contactor when it comes to the longevity and protective aspects of the SureSwitch. I know I’m giving them something that will last a long time and reliably keep them comfortable.
You can learn more about the SureSwitch at https://hvacrschool.com/SureSwitch. I also filmed a video showing how to replace a contactor with a SureSwitch at https://hvacrschool.com/videos/easy-contactor-replacement-with-sureswitch/.

—JD Kelly