How to Set Up the ICM 493 Surge Suppressor

MOV surge suppressors don’t offer full protection, but they are the best financially feasible residential options on the market. To get the most out of your MOV surge protector, you should make sure it has a short, well-connected ground and proper wiring. MOVs can fail when they take large hits or several small hits over time; when MOVs fail, it’s best to replace all surge suppressors.

The backside of the surge suppressor contains all the wiring. The left-hand side monitors voltage, and the right-hand side sends voltage to the condensing unit. Once the ICM 493 understands that the voltage is in line from the left, the board activates the contactor, which sends voltage to the load connected at the right (the compressor and condenser fan). The board also has a three-amp low-voltage fuse. The ICM 493 also has four Tapcon screws, though the upper left one can be tricky to access. Ideally, the ICM 493 should be perfectly level and have its outsides (against the wall) sealed with silicon to prevent water and bugs from getting in through the back.

To begin programming the ICM 493, press the “SETUP” button to scroll through the settings. It will ask you to input the line voltage (208 or 240).

The control will then ask you to input the over/under-voltage percentage. We typically set that value at 5%; when the control detects more or less than 5% of the line voltage, it will open the contacts.

You can also set an anti-short time delay, which we normally set for two minutes (it starts at 30 seconds).

Reset mode can be set for one trial or auto; that is something to discuss with the customer and see what they want.

Allowed MOV fails can be set for four or five. Four shuts off the unit when only one MOV is remaining, and five allows the unit to keep running even when all five fail. Setting the ICM 493 to five MOV fails will prevent nuisance shutdowns. MOVs or metal-oxide varistors work by directing the current to ground during high-voltage events.

To calibrate the ICM 493, hold the up and down arrows simultaneously until the line voltage starts to flash. Then, use the RMS meter to check the line voltage between L1 and L2. Once the voltage has been dialed in, press “SETUP” again to make the ICM 493 start; it should display the remaining MOVs and the line voltage when you press the appropriate buttons.