I’ve installed a surge protector on the disconnect of the condenser but the LED doesn’t light, indicating that it’s not operating. I’ve double checked connections and they appear OK. What’s up?
With all of the electronics that we now have in our HVAC/R systems, they can be very sensitive to power supply variations and surges. This can be a major reason for failure in applications. To protect against this, Surge Protective Devices (SPDs), or surge protectors, have become very prevalent.
Surge Protective Devices
These are very easy to install, however, there are some key things to keep in mind.
They are connected directly to the disconnect or breaker panel. The most common installation mistake is the connection to ground. Not that the ground lead is not connected to the ground buss, but that the ground buss is not a proper ground.
There should only be one, “common ground per system to eliminate the possibility of a differential in ground potentials.” Once that has been verified, the ground resistance must be measured. It cannot be assumed that it is a proper ground. The maximum ground resistance should be 25 Ohms. The optimum ground would measure 5 Ohms or less. Exceeding this resistance will result in improper installation, and the LED will fail to light on the SPD. This could result in no surge protection.
Proper grounding is not only a safety concern, but it is also a critical component for correct performance of many of our electronic controls and devices, including surge protective devices.