Looping on/off switch (10 s on, 0.5 s off)

Question

I bought a 24 V shower booster pump,

and it has this crazy behaviour that it shuts down after 10 - 12 seconds. When I restart the pump, it starts again for 10 - 12 seconds.

It is useless now and pumps that do not have this "feature" are outside my price range.

A simple solution would be to restart the pump every 10 seconds, with 0.5 second paused.

But how to make a looping relay that is NC for longer time and NO for a really short time??

Edit: No, no schematic of the pump, just + and -. Inside sealed with epoxy.

No, not a pressure switch. If I limit the incoming water flow it should take different time to reach pressure. Always about 12 seconds (not stopwatch)

Thanks for thinking with me, but obviously I thought of those.

Sure, there is flow sensor to start the booster pump when the water starts. Why the heck they built something inside to stop after short time?? And don't restart until the water stops, and starts again, or the power is interrupted.

I found with the help for correct search terms the following hardware:

It can do continuous loop at different timings for stop and start.

I totally agree that this is not the best way. The pump should work continuous without this type of trouble. Thing is, dry testing one doesn't do for long 10 second period, the fault is not detected. After installing, there is no longer any opertunity for return or warranty

Note: It's not being used for shower, but to boost water pressure coming from a deep well pump. After 35 meter that is pressure too low to be used for spraying the plants outside

Answer 1

How to make a looping relay that is NC for longer time and NO for a really short time??

A 555 timer IC with a relay allows you to do this. You can find modules that already do this for you, a potentiometer and jumpers help you set the right durations.

The 555 timer IC has been around in decades and comes in different flavors - there are some that work up to 18V at least.

http://www.555-timer-circuits.com/555-on-24v.html shows how to hook one on to a 24V supply directly (but it will not be able to drive your pump without a relay).

A google search for "555 timer with relay 24V" gives quite a few results. You can find ready to use modules for less than $10.

Keep in mind that you can not tune the 555 time for a duty cycle between 0 and 100%, it can only be tuned for about half the range. By using the NC or NO output of the relay you can achieve the functional duty-cycle that you are looking for.