Help needed. 3 amp breaker switch replacement please!

[5AZSooners]

Hello, I have a 3 amp "valve" breaker switch that won't stay on. It controls 4 automatic valve actuators and has worked great for 4 years. Took a $5 bet on just the breaker switch, but the new one still triggers.

My next option it seems is to replace the entire "box". But I wanted to see if anyone else had any ideas.

Here is the picture, the model number on the box is p/n:520128.

Thanks a bunch!
BJ