Solenoid cycles on CO2 to reactor: how often is too often?

SoloSK71 · #1 01-31-2017, 03:27 AM

Most 'hobby grade' solenoids in most hobbies at STP have a mean life expectancy of 10,000,000 cycles.

Even discounting that by an order of magnitude, you should not see reliable chance of failure in your tank's life span at 60 cycles per day.

Using the electronic method as opposed to physical, the coils usually have 10,000 hours MTBF, and assuming the cycle time is 2 seconds (I am guessing here) then you are 120 seconds a day (2 minutes) or 12.167 hours a year. Again, statistically, not much chance of failure in your tank's life span.

Having said that, the failure curve for these items is heavily weighted to the left, so take what I said with a grain of salt. You should still have no problem at all with that duty cycle.

Charles

brotherd · #2 01-31-2017, 03:48 AM

Quote:

Originally Posted by SoloSK71

Most 'hobby grade' solenoids in most hobbies at STP have a mean life expectancy of 10,000,000 cycles.

Even discounting that by an order of magnitude, you should not see reliable chance of failure in your tank's life span at 60 cycles per day.

Using the electronic method as opposed to physical, the coils usually have 10,000 hours MTBF, and assuming the cycle time is 2 seconds (I am guessing here) then you are 120 seconds a day (2 minutes) or 12.167 hours a year. Again, statistically, not much chance of failure in your tank's life span.

Having said that, the failure curve for these items is heavily weighted to the left, so take what I said with a grain of salt. You should still have no problem at all with that duty cycle.

Charles

What he said

Delphinus · #3 01-31-2017, 03:32 PM

Thanks for the info, very helpful.

The solenoid itself is already a replacement, or rather, a rebuild based on a solenoid I bought off ebay because the original froze on (it was a decade old). I had hoped I could unfreeze the original but I couldn't (and it turns out you can't lube these? So I guess when they're done, they're done). Between that and the number of options of feed pumps I've gone through (tried a peristaltic pump but the gears wore out after a couple months), then some other pumps that eventually weakened ... etc ... I feel that "eventual failure of parts" is a sort of given in this hobby.

Just wanted to be sure I wasn't in the territory of "Wow! That's a really burdensome way to dial in your reactor, there's an obvious better way that you're overlooking".

maron6977 · #4 01-31-2017, 08:44 PM

I personally think it's too much . If it's cycles that much - just turned down you bubble count !
Right now , I don't think mine has cycled in days .
Also , when first set up (& didn't know anything) found solenoid shut off but was still bubbling (slowly) .
So just to cover problems - turn your bubble count down . As far as I've read , should only cycle 2-3 times a day

maron6977 · #5 01-31-2017, 08:49 PM

Oh Ya . Also they make 1/4" needle valves , work way better - been there, done that .

Delphinus · #6 01-31-2017, 09:40 PM

Got a link for a 1/4" valve? I'm currently using this one (which seems to have good customer feedback, but is 1/8" not 1/4")

I have the thing currently barely open. If I close it any further I don't get consistent gas flow into the reactor. I've tried lowering the regulator output pressure so that I could open the valve more, but again I get weird effects when I do that. Ie., either the bubble rate stops altogether, or the reactor effluent stops .. stuff like that.

I'm all for using less CO2 though so if the answer involves moving to a different needle valve I would consider that.

Delphinus · #7 01-31-2017, 09:45 PM

Also are you using a 1/4" regulator or do you use an adaptor to the 1/4" needle valve?

maron6977 · #8 02-01-2017, 02:30 PM

Quote:

Originally Posted by Delphinus

Got a link for a 1/4" valve? I'm currently using this one (which seems to have good customer feedback, but is 1/8" not 1/4")

I have the thing currently barely open. If I close it any further I don't get consistent gas flow into the reactor. I've tried lowering the regulator output pressure so that I could open the valve more, but again I get weird effects when I do that. Ie., either the bubble rate stops altogether, or the reactor effluent stops .. stuff like that.

I'm all for using less CO2 though so if the answer involves moving to a different needle valve I would consider that.

Sorry , I should have been more clear.
I use a Milwaukee reg & solenoid w/bubble counter . Glycerin in bubble counter . 1/4" needle valve for effluent. I have a Geo 612 reactor & run at a PH of 6.5.
Also just added a second chamber , so effluent runs thru vertex reactor body filled with media & overflows into sump - trying to raise tank ph , seems to work.