Pull power too before washing with water or it may get real exciting.

I bet you got a small leak and press is down. A charge will probably get you through the summer.
I had an old Lennox, 18 years old and it was noisy and under performing. I got it checked out and made it through the summer on a charge but it was getting worse by summers end. I put a new one in this past March and boy am I glad I did the way weather has been. The old one would have broke for sure.