My system shows no flow skimmers were clear it has pumped to the returns. As soon as I backwash or pump to waste and turn it back to filter it will say it is working for about 1 minute. All wires appear to be connected. I pulled them all and reattached them but nothing. I replaced the flow switch last summer. i'm pretty sure it is a part on the unit. i just dont know which to replace. Any help would be appreciated.