Hvac tech replaced coleman thermostat #3110-378 with a new thermostat.everything works but the fan will not stop running.the only way you can cutoff fan is by turning off the heat breaker

Check the start / run capacitor and the start relay

The booster motor? Do you mean the inducer motor that helps push the exhaust? If the inducer motor won't shut off when the thermostat is satisfied and everything else does shut off, it sounds like the contacts on the relay that powers the inducer are at fault

clean well all the small drainage with bleaching liquid and soap it with scented soap.also at the back of the unit that are having small drainage and through the drain hose

Running the equipment on 72 degrees would cause the compressor and fan to work harder on hot days. This will definitely place more strain on your capacitor. These capacitor problems usually happen on the hottest days. I would suspect the capacitor, not the fan. I'm an HVAC tech, so I would Check both with my multimeter

my coleman 7330 fan only runs when ac unit is on and then sometimes shuts off and then restarts

Ice forming on the suction side is normal and on really humid and hot days you will see it as the unit runs longer and the suction is very cold. I am not certain as to why the tech told you to use a sprinkler on the system unless he thought you had a Hi head pressure or he just wanted to calm your concerns regarding the icing as you say the fan came back on ????. .. now with all that said it appears something got wet and shorted out .. could be a number of things . the outdoor fan contactor, the tstate wiring, or the motor got wet and burned out... was the unit cooling well even with the ice? I think it should have .. let me know.

If the thermostat is ok which it probably is then your sequencer is most likely stuck i would say. You could verify that by removing 24 volts to the sequencer to see if it will shut down the heater
When low voltage from the thermostat is applied at the base of this sequencer it heats a bi-metal and turns on each coil and fan in a sequence that will insure the breaker don't throw from the power surge AND warm air comes out the vents when that fan comes on. I would start there.

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The only thing that is going to but the fan off is the thermostat. When the fan stops, immediately check the thermostat on the wall. See is there is power between the B terminal and the GH terminal. If none, then replace the thermostat. If there is, then replace the control board in the AC. That means that the fan relay on the printed circuit board is weak.

some of those fan motors will not run unil the defrost thermostat has closed.

You have a bad control board. Replaced the board