@pjnarkhede
The E183 error means that there is an overcurrent error on the thermostat, indicating that the electrical current on the thermostat wires connected to the Nest Thermostat has spiked multiple times, causing the internal breakers of the thermostat to activate in order to protect the thermostat base plate and system components from damage. This is typically points to an issue with the outdoor unit's contactor and not a freon leak.
You can check to see if the outdoor unit contactor is engaging by standing next to it and have some else set the thermostat to cool, you should hear a loud clunk. If you don't then there is a problem with the contactor or its capacitor.
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