Electric Air Valves: One or the Other?

Every time I try to visualize this it makes no sense. Is there any way you could draw a picture of the circuit and explain a little further what it is you're trying to accomplish?

All depends on the functionality you want and the available valve types. Obviously the manual valves you have when closed, are leaving their output side open, so electric ones can't build-up pressure. S.M.

Sounds like you need check valves.

Ok lemme.try to explain this again. Manual valves were in play already. Added electric ones in parallel. I t off supply to feed both valves. I t off a and b lines coming off manual valves and added electric a and b on same a and b from manual valves. When I energize the electric valves the pressure bypasses through the exhaust on the manual valves and doesn't work. Bit works when I use the manual valves.

Having no information on the valves themselves, see #3.

Both valves have b port norm open and a port blocked off till lever or coil energized.

OK, what do you really want to know?

Presently, your manual valve is obviously allowing back flow. No amount of additional information will alter that reality. Your electrical valve does not leak. Still having no meaningful information on the valves themselves (mfg part # etc.) you have no options except those below.

Your choices are to either:

1. Buy new manual valves that don't leak.

2. Install a valve, of your favorite flavor, to block the back flow.

3. Always use the manual valves.

4. Block the offending ports with a plug.

Consider first just the manual valve system. Do you actually need to have the exhaust open when the valve is OFF?

If not, just block the manual valve exhaust and it will work (assuming the electric valve also has its exhaust blocked).

If so, you'll need to explain more about what functionallity you need (e.g. should the manual valves override the electic valves, or what?).

The obvious correct answer to the question in your post is... NO, YOU DO NOT NEED TO ADD A BALL VALVE. There are most certainly other options.

where does the air bypasses? suction or discharge? if on the discharge side, install check valve on the manual valve discharge. if on the suction side, a ball valve or any isolation valve will just be fine. good luck!

Cpould you indicate the shematic of the 2 valve types ? 2 positions ? 3 positions? It would help to give a correct answer since we will not be blind.

Post a schematic. Threads like this can go around and around without one.

For whatever this is to work, you would of course have to close the manual valves, so that the electric valves are in control.

I use the manual valves the operation works fine but when I use the electric one it bypasses

Do you really mean electric "one?" It sounded, at first, like you had two electric valves.

Manual valve you open and close slowly. Electric valve are quick opening - quick closing. Tray replacing with a motorized valve slow opening-slow closing.