I had a volume problem. It took 30 seconds to gain 0.5 pounds. I unplugged the hose and took a deep breath. I removed the end that connects to the valve stem. The rubber seal is pushed fully into the airway, stopping the flow. He pulled out the washer, wound about 15 turns of tape, and screwed the end back on. Now everything is good. Two months later: The POS sensor is defective. stuck at 26 psi. Pulled out the batteries and it won't start.