Dosing Pump Safety Box

[Wall_Tank]

When using an controller or timer to run your dosing pump, it's easy to fat finger a time or put it in manual and leave it running.

I use a simple Omron timer module to make sure the pump can only run for a certain amount of time.  The Controller or Wall Timer powers this box, then the pump plugs into the box.  I normally set my safety timer for about 30 minutes.   Yes, this does add another failure point to keep the pump from running.....but the pump stopped is a whole lot less catastrophic that a pump stuck on.

One other point for those apex users, please make sure you are using an EB-4 or outlets 4 or 8 on an EB-8.   These outlets are relay controlled.   Other outlets are solid state, and may not always shut off under the very small loads of dosing pumps.

[Agame43]

 Great Post, I would ask if you could provide me with a schematic for wiring? You are so correct a 30 minute timer would have saved me 2.5hrs of my pump dosing extra because of my mistake, 30 minutes works. 

[lazylivin]

Paul made one of these for me a couple years back. It has saved me at least twice from disaster.

[Wall_Tank]

I don't have it written, but I use this timer.  I can usually find them on ebay.  I have 4 of these as spares or for new builds, as they take about 2-3 weeks from china.   All in with the box and pices parts, there is about $25-30 in parts.

Omron H3Y-2 110V 0-60m

If you look at the pictures, the relay wiring is on the side of the relay.

4x4 (or 6x6 if you want 2 channels)
Timer relays with base (You can bolt these in the box, but actually superglue works really well)
Extension cord (Cut in half  and wired to the box)  A round hole for the cord is easier than a square cutout in the picture above)
Clear Acryllic Cover (I cut these, as the cover that comes with the box is not clear)
1/8" audio jack...I use these for the 2 wire alarm circuit back to the apex.

When the dosing pump controller turns on, the box is powered and the power also goes through the NC contacts on the relay.  IF the timer expires before the Controller turns off, the timer relay changes state, opening the contacts to the pump.    I also connect the other side of the relay to my apex as an alarm.

If it would really benefit, I guess I could draw it up. 

[Gary]

Paul,
Is the timer incorrectly labeled on the ebay site? It goes 1-60 seconds and not minutes?
Thanks,
Gary

[Wall_Tank]

Paul,
Is the timer incorrectly labeled on the ebay site? It goes 1-60 seconds and not minutes?
Thanks,
Gary

While I have had incorrectly marked timers from China.....I just linked the wrong timer.  I fixed it.   (I had not had enough coffee yesterday morning)

[Gary]

Thanks!