Pressure relief device replacement of a power transformer.

We have 85 Mva power transformer for substation with two PRD. Team does periodic actuation of alarm lever to actuate and release knob to normalize to see signal and its working. Now when we are actuating the alarm lever its not able to hold with spring and immediately goes back.

I am thinking of replacing it with spare PRD . If i close the conservator tank valve , can I remove the PRD on transformer body and install new one??? is that so easy.

Need guidance as how to do it .

Thanks