How to compare an AC signal with a DC reference using a comparator?
The MIC7221 is a comparator, not an op-amp.



  The AC RMS voltage at the input is 33 V ...



Your schematic shows only one connection between the mains circuit and the low-voltage circuit. Therefore there is no return path for your mains signal and the circuit should fail or operate intermittently. Be aware that you must treat your complete circuit as live as there is no isolation.



  ... and the reference voltage at pin 3 is 2.6 V.



R4 is not required and will skew the voltage set on the pot. Remove it.



  Voltage at pin 4 is 2.2 V. The AC RMS voltage at the input is 33 V ...


That means the voltage on C1 must be about 220 V DC (since you have a 100:1 divider). This conflicts with your 33 V reading.

If  your pin 3 and 4 readings are correct (V+ > V-) then the output should be high, T1 turn on and LED1 should light.


  I wanted the opamp to go low when the voltage dropped below 30 VAC.


Again, it's a comparator. If everything is wired correctly then set the input voltage to the required threshold value and adjust the pot until the output switches.

You need to fix the disconnect between the low-voltage circuit and neutral.