E7 appears on the display and the water tank is empty or correctly installed.

Safety: Turn off and unplug the unit before removing the water tank.

Steps:

• Remove and inspect tank: Pull out the condensate tank. Check for dirt, scale, or debris around the float mechanism. Ensure the float moves freely up and down.
• Clean float assembly: Rinse the tank with warm water and mild detergent. Remove any slime or mineral buildup that could jam the float. Rinse thoroughly and dry.
• Check tank seating: Reinsert the tank firmly until it clicks into place. Many Argo models have a small lever or pin that must be depressed by the tank to close the level switch.
• Inspect level switch: With the tank removed and power disconnected, locate the tank level micro-switch or reed switch inside the tank compartment. Check for broken actuators or loose mounting.
• Test switch: Use a multimeter to check continuity of the micro-switch when manually pressed. If it does not change state, replace the Argo water tank level switch.
• Reassemble and test: Refit the tank, restore power, and confirm that E7 is cleared and the unit runs with the tank properly installed.