I recently purchased a brand new Normally Open 453P solenoid for a weep system. I noticed the valve doesn't shut clear off when energized. Thinking maybe it had dirt in it I opened it up and noticed a small hole in the piston which makes me wonder if it is suppose to leak. Is this hole suppose to cool the valve or something while the valve is energized for long periods of time or something? I am tring to decide to send it back or if it is suppose to leak?