When I looked up how to measure varistors, I found that the varistor's value should be 0L ohms (Over range, infinite resistance) when measured by a DMM set to test resistance, to indicate its validity.
When I tested the varistor (INR 14D681S) with my DMM (Set on resistance test mode), the result was 0.650 MOhms (Knowing that both its legs are attached to the PCB).
It's at the gate of receiving the VAC to protect the entire circuit (I point at it with red arrow.) One of its legs is connected to the ground terminal & the AC terminal, when the relay is engaged via a parallel connection with a capacitor (470n K275V~ 436D MKP X2,) the blue box above it.
There's no sign of burning or explosion on it as I saw in demo videos when it receives higher voltage than its value.
Do I need to detach one of the varistor's legs as regular resistors to get a right reading?
Do I need to detach it & test it with DMM if there's no visible sign of damage on it?