Why Stenner?

[Patrick_B]

I've not had a need to spend much time in here folks, so I am asking for some leniency here if you will. Not here to argue brands, just flatten my learning curve.

I've been working with chemical injection pumps a long time and have primarily used diaphragm pumps of some type, usually LMI, but all the major brands. Most often, we use them because we are injecting into pressured systems, but sometimes, it's just out of familiarity. We use them for everything you can imagine, including acid and bleach, but I've never used a Stenner. I remember seeing them in small open systems pumping bleach in my early days, but haven't encountered them since. Excepting here, and a couple of reference pools I've been to see.

I would guess they are less susceptible to off-gassing since they don't compress the liquid, or is it as much a cost/ease of use issue? Nothing LMI is inexpensive, so I would understand if that was in play.

They seem to be the preferred choice here, so I'm just curious why. I'm looking into this more before I build so any feedback is welcome and appreciated.

 

[Bama Rambler]

There a few reasons I like them. One, as you said, is because it's a peristaltic pump, and because of that, you don't have to worry about gassing. Second, since it's a peristaltic pump you don't need inlet and outlet check valves. Third, with Stenner, to change pump size, you just change the pump tube. Fourth, almost anyone can repair one of them. And fifth, they're relatively inexpensive.

I also have used metering pumps for the last 30 years. There's not many brands or types that I haven't had experience with. The reasons listed above are why I chose Stenner. That's not saying that other pumps don't work, and there are several people on the forum that use different pumps.

 

[Patrick_B]

Thanks Bama, I figured you would have a good answer. I really don't know what I will do yet in terms of Chlorine automation, but I'm going manual on acid to start out with. I have stuff laying around, but I'd like to give these a try, if nothing else but to do something new. Right now I only have questions about pool injection set ups, but I'm learning. I really appreciate the feedback Sir, thank you.

 

[Isaac-1]

I actually do use an LMI pump here, in fact I am on my second one (both bought off ebay, both new old stock / spares, the latest one was missing some accessories, but still had the factory plugs installed). Currently using an A941-155SI, this was missing its inlet and outlet valve, which I used the parts (ceramic balls) from my old A921 pump on, so may be different specs than the 155SI (steel ball?). Having said this I do tend to suggest Stenner pumps here, for the simple reason of lower maintenance requirements, in the last few years of using LMI pumps I find the diaphragms have to be replaced every 12-18 months, along with the valve springs at a cost of $50+

Ike

p.s. the built in timer went flaky after a couple of years on the first one, and I must admit I like the digital controls on the 941 series much better,

 

[Patrick_B]

Ike, you ought to be getting much more time out of those. You let the pump run dry often? That's what usually does them in. The A series is the way to go in small LMI pumps if you ask me. Stay away from the P series. Steel check balls are usually for heavier liquids in my experience.

 

[Isaac-1]

My guess is it was an electronics defect (maybe an electrolytic capacitor going bad), it still runs, but pumping rate varies considerably with temperature changes (1 pulse per minute when the mechanical room is fairly cool, say around 75 degrees at night would turn into 3 or 4 pulses per minute when it hit 100+ degrees during the afternoons).

Ike

 

[dschlic1]

I know that in the municipal water and wastewater area, LMI pumps are not highly thought of. However we are talking about a whole different class of usage. These applications demand 24/7 operation and if they fail it could result in a reportable incident ($$$).

 

[Patrick_B]

People seem to love em' or hate em. I've had most of them endure tremendous 24/7 duties, with the occasional lemon. More in the love category for me.