Arrived on site for no cooling on the top floor AKA attic. Check temperature split with probes temperature split with about 1° of difference. Disconnected the float switch. After disconnecting the float switch the temperature split peaked at 23° difference. Installed a new float switch, temperature split dropped back to two to three degrees. Left the float switch there unwired to the air handler and temperatures split increase again 20° difference. Made customer aware that there is no float switch in the unit and that we will contact him for the replacement.