Sean,
The compressor receives its signal too turn on and off from the air handler. So if you engage the float switch in the attic and the air handler shuts down you are good too go. But you are going to have too find another means for making up for the additional exercise that you will be loosing. LOL
Your right, some just shut off the compressor and when the switch drops it kicks right back on.
Some I can hear the freon in the line stop and others the system will shut down. Its just some that your not sure.
The attic today was no prize to get into. Gambrel roof with an upstairs so not much room.
I’m curious as to why you would want the air handler to run when the pan was full? Shutting the AH down will also shutdown the compressor. Wouldn’t it be more obvious to the homeowner that there is a problem when there was no air coming out of the duct work?
What ever happened to the touchy feel method if the compressor is off the suction and liquid refrigerant lines become ambient pretty quick and they are right in front of you:D:D:p