SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I am doing winterization first time with a 6-gallon air compressor. I have 8 zones with 8 Hunter RSV valves (no flow control knob, no master valve). I set the compressor regulator at 50 psi. After blowing water from Zone 1, I closed Zone 1 valve and opened Zone 2 valve from controller. When blowing Zone 2, I saw water bubbling out from both Zone 1 and Zone 2 heads. Then I closed Zone 2 and opened Zone 3 valve to see what would happen. When trying to blow Zone 3, I still saw water bubbling out from Zone 1 and Zone 2 heads, but not from Zone 3. It seems that Zone 1 and Zone 2 valves stayed open after the 1st attempt of blowing even though I closed them from the controller. Is it possible both Zone 1 and Zone 2 valves are damaged (won't close)? I understand I can only blow 1 zone at a time and it will take a couple tries to complete each zone with such a small compressor. If the valves are not damaged, can I close them manually without turning on the water supply (so I can winterize one zone at a time)? Thank you