osmolator metering pump voltage

[johns]

Roger-

Finally got my osmolator last week and just set it up on the sump tank last night. Something tells me that this might be a stupid question, but I have to ask - am I supposed to run the metering pump at the 9v setting or the 12v setting? Is it just a personal preference decision? Or are there any pros/cons to the different settings?

Also, one other thing - This is being sort of picky, but I decided to let the pump run to see how long it would take to shut down. but instead of taking 10 minutes, it took 15 minutes before the pump stopped working. I would personally prefer if the pump were to shut down after 3 or 4 minutes. Having it run 5 minutes longer than it's supposed to probably isn't going to do much additional harm (my storage tank will probably be pretty empty by around the 10 minute mark), but it isn't going to help matters.

 

[rvitko]

Unfortunately with eletronics every component has an accepted degree of variability. This timeout is controlled by the discharge of a capacitor and some resistors gating that. All of these components have 5% margins so the theoretical rating is 10min but somewhere between 8-14 minutes is the general rule of thumb. I don't think you would want 3-4 minutes as sometimes it takes a couple minutes just for the pump to prime in a new bucket of water. It also is further slowed if you have the calcium dispenser. Also figure in the pump is supposed to run about 8-10 seconds after it detects the water level and a brand new unit isn't as accurate in detecting water level because the hydrophobic properties of the plastic cause an air film to form. Rinsing a new sensor with hot water helps, a few days after being put in use the accuracy will be optimal. The float is your main overflow safety and the timeout is only going to be called on if the pump is dead or the tank/sump is leaking. At 12V the pump has more power and this is needed for a kalk reactor or our calcium dispenser. It is louder and will have a shorter life. At 9V it is weaker but the life will be longer and it will be quieter.

 

[johns]

Thank you Roger. As usual, you have the quickest response on RC.

Well the reason I say 3 or 4 minutes is all I need is that I dont actually have very much evaporation currently (maybe half gallon a day?). I dont suspect it is going to take very long to top-off my system. If the pump runs more than 2 minutes at a time, I'd be surprised. I'm not currently using the a Ca dispenser, but who know's...maybe some day.

The main purpose of my osmolator is for while I am away for long periods of time. But I figure, since I have it , I might as well start using it routinely. I realize that the float switch is my main saftey mechanism, but since I'm thinking in terms of this operating on it's own for a week to 10 days, I figure another saftey mechanism wouldn't hurt. And I just assumed the time-out would be that second back-up.

As it turns out, the time-out cant really be that second back-up. and if it runs 15 minutes it may empty out my whole storage tank anyway, and the pump may even pump air for a minute or 2. Isn't there a danger in the pump running while dry.

BTW, I realize that these are pretty uncommon scenarios (hopefully). But I'm new to the hobby, new to all these products, and I'm planning to be gone for a while in the near future. So I am probably being overly-concerned.

 

[rvitko]

It is very rare for the optical sensor to even fail and I have never had the float fail too. Every failed unit I have seen fails in the off position so I would have no worries. The pump can run dry because it is just a DC motor with a shsaft through a rubber seal- imagine the hobby motors from radioshack sealed up and with an impeller on the end. They need no water to cool them.