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STC Solenoid Valve - No Worky

I've got a couple 4 way solenoid valves made by STC (imported by STC) that don't seem to work. 12VDC Model 4V310-1/4. They are NIB, but I bought them quite a long time ago for the project I am currently working on. I don't even recall who I bought them from, but they were not super cheap nor excessively expensive. Around $40 if I recall.

I've used plenty of simple on-off solenoid valves in the past. They just work. You hit them with the rated voltage and adequate current and they reverse condition. Open/closed

When I hit these STC valves with 12VDC from a 12V battery (plenty of current from a battery) they click and a red light turns on, but the shuttle that changes the port connections of the valve doesn't move.

I'm looking at the installation instructions from STC right now on their website, and I don't see anything that doesn't make sense. Is there a setting or setup I am missing or do these valves just not work?

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Yeah I dropped an email off to STC, but I am sure I won't hear back from them before Monday at the earliest.

Reply to
Bob La Londe
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Are you sure the battery is good? Old sealed AGMs can develop a high internal resistance but still read above 12.6V on a voltmeter. A brake light bulb is a good test load.

Reply to
Jim Wilkins

It's a pilot operated valve: the solenoid actuates a small valve that controls the spool of the main valve with air pressure. If there's no air supply, or inadequate pressure, the spool in the main valve won't move. The triangle under the solenoid in the valve's schematic represents the pilot.

Reply to
Ned Simmons

What does the triangle to the left of EA mean?

Reply to
Jim Wilkins

Also the pilot. I'm not 100% sure, but I assume it means the pilot operates in both directions, with a bias spring (the zig-zag on the left) to hold the valve in the normal position when there's not enough pressure to operate the pilot. In the schematic, all the actuators (solenoid, spring, pilot) "push" the spool away from themselves. Another clue that this is a pilot-operated valve is the fact there's a minimum pressure shown on the labels in the pictures of the valves. A direct operated valve would not typically have a minimum operating pressure.

Reply to
Ned Simmons

On 9/21/2019 5:00 PM, Ned Simmons wrote: > On Sat, 21 Sep 2019 19:26:40 -0400, "Jim Wilkins" > snipped-for-privacy@gmail.com wrote: >

Hmmm.. I guess I am going to have to assemble a more complete test setup for it then. I did put air to it and place a finger over the currently active output port to provide back pressure for testing.

In the mean time I do have a 4 way manual valve that would do the same job. It just requires more plumbing since I can't just run 2 wires to the front of the machine for a push button.

Reply to
Bob La Londe

Here's an inexpensive adjustable current sensing switch and indicator that you might find useful in a control system.

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I bought it to show if my refrigerator's compressor is running when a thunderstorm approaches and I want to move the fridge plug from the wall to isolated UPS battery power, immediately if it's off or after a

5-10 minute delay if it was running.
Reply to
Jim Wilkins

Well ... based on those instructions, the DC coils may be sensitive to polarity. Obviously, AC coils cannot be so. :-)

It looks (from the photos) as though the 4-way has white and black leads from the coil. The 3-way has red and black.

But it seems the Red and Black are for DC only coils, and the White and Black is AC only. So it may be that there is a permanent magnet in the DC valve, so polarity determines which way it tries to move when connected. Black to minus and red to plus on the battery.

If both wires are the same color there is no polarity sensitivity. So what colors are your wires?

I hope that this is some help -- but it is already Monday, so unless they are slower, you should have already heard from them.

Good Luck, DoN.

Reply to
DoN. Nichols

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