The Panel Comm. Lost Check CCT. Panel-220 error on the Handheld Transmitter (HHT) refers to a CAN communication issue. The error asks the user to check the connection between the control panel and the receiver.

If you get this error, check the CAN H and CAN L harness wires for damage or a loose connection.

Also check that the error isn't a connectivity issue between the HHT and the receiver. If the LED light on the receiver is solid green and the LED light on the HHT is bright green, this indicates that the remote and receiver are connected.