Here is a valve tip that might save you a little time. Comment or post one of your own. Manually bleeding a valve: Use the solenoid or use the external bleed screw? Why is there a manual bleed screw? I find that most do not fully understand the differences between the function of the external bleed screw and the internal bleed using the solenoid. Of course, the obvious answer is that the external bleed leaks water off the top of the diaphragm to atmosphere. The internal bleed leaks water off the top of the diaphragm through a port to the outlet side of the valve. You won't have any water leaking in the valve box if you use the internal bleed. So, why use the external bleed screw at all? First, let's talk a little about how the diaphragm responds when you bleed a valve. The diaphragm moves (open or closed) in response to a difference in force on each side of the diaphragm. If the force is equal, the diaphragm won't move. If the force is greater on one side, it will move away from that force until the forces become equal or it encounters a physical barrier. Let's consider the internal bleed. When the solenoid is twisted to bleed the valve, it relieves pressure from the top side of the diaphragm and the diaphragm opens. However, at low flows, it does not have to move very far before the pressure equalizes and the forces are equal. This is due to the pressure drop across the valve seat and the back pressure due to the water in the pipe connected to the outlet of the valve. At very low flows, the diaphragm may lift off the seat so little that debris can become stuck between the diaphragm and the seat. When the valve closes, the debris causes a leak path and we have a 'weeping' failure of the valve. The first reaction of many after bleeding the valve with the solenoid several times is to take the bonnet off and clean the seat. But next time, let's consider something else. Use the external bleed screw. When you open the external bleed screw, the top side of the bonnet is opened to atmosphere. How much back pressure is there on the top side of the diaphragm? NONE. ZERO. (One atmosphere, actually, but give me a break!) So, when does the diaphragm stop moving? It does not stop until it encounters a physical barrier, the top of the bonnet. This happens regardless of how low the flow is. This is very different from the condition caused when you bleed the valve internally. Maybe that piece of debris will get washed out because the diaphragm is wide open! Try this next time you have a weeping failure. You might get lucky and not have to take the bonnet off to clear that debris.What other uses do you have for the external manual bleed screw? I have a few more, but let's see what you have to say.