Arduino as protection for heating system

Hello guys, I want to build a protection module using arduino uno for a heating system that uses coal.

In case the water trough the system goes over 70 degrees Celsius or 3.5 bars pressure I need arduino to power a buzzer as an alarm..

I have the arduino uno starter kit that comes with 2 buzzers but I think they are too small.

I think I will need an adjustable pressure switch, a temperature sensor, power supply and a bigger buzzer.

What do you think about this??
Can you recommend me some parts that work well with arduino uno?

I like Grove components.