stenner injector- water coming out in reverse

texasmax

Well-known member
May 24, 2010
118
Dallas, TX
#1
I've had a bleach injection setup for a number of years, with the stenner injector after all the equipment, in the top of a horizontal pipe just before going back into the ground at the pad. Nothing's materially changed recently. I noticed liquid dripping out of the output side connector of the stenner pump. When it wasn't running. I disconnected the line at the injector and had myself a little bit of a water fountain. Because, what's another 20 bucks, I replaced the entire injector as opposed to just the backflow piece. Now, I've got just a slow drip. So, there was an issue with the backflow manifold piece, but it's still leaking out. Am I pushing too much water through return plumbing that's too restrictive? Maybe. This is on a 2-speed pump running on high (it's usually on low except for special occasions). Not sure what would have changed, but, trying to figure out what to do to fix it. It's probably not a big deal that it only happens on high speed (I'm assuming it doesn't happen on low, but have to go back out to test it). Also assuming there's no way bleach will get pushed through there (with pump on high) with all that reverse pressure on it. So, only run bleach when I'm on low. Sure. Just thinking what else I can tweak here. The depth of the injector into the pipe (2") is to spec when I first installed it (was it supposed to hit the center of the pipe? whatever it was, that's what I'm doing). The one thing I can think of is, cut the tip at a 45 degree angle such that the water flow hits the "back" and the bleach goes forward in the flow direction, if that makes sense. Currently, it's cut normal/flat.

I'm not worried about water loss when I'm running on high because it's not that much (even though there are "special occasions" that last several days). I'm not worried about busting the seal on the outlet of the pump where it connects to the bleach line (though I could see it wearing away over time). Anything else here I can try?

Thanks!
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,815
SouthWest Alabama
#3
If there's water leaking from the outlet side of the stenner pump either when it's running or when it's off, then you either have a ferrule leaking or the pump tube is cracked. If you haven't changed the pump tube in over a year, I'd change the tube and trim off a couple inches of the feed tube and replace the ferrule. Make sure you have the tube nut tight, but not too tight.

If you want to try tightening the tube nut at the pump tube that may buy you a little time.
 

texasmax

Well-known member
May 24, 2010
118
Dallas, TX
#4
Shouldn't I expect a little leakage at the outlet side (when it's off but same difference) simply because of all the pressure coming back up the line that connects the outlet to the injector? I certainly agree, I at least need to replace the ferrule and snip some tubing (or replace it) so it's a fresh piece at and around the ferrule/outlet. But the root cause here- shouldn't I not have a high-pressure backflow coming out of the (brand new with brand new backflow preventer) injector?
 

gary300

LifeTime Supporter
Dec 15, 2014
499
Riverside California
#5
Normally, back flow is prevented because the pump tube is squeezed tightly against the pump housing by the three rollers. A cracked pump tube as mentioned above would cause of leak. The check valve in the injector prevents a whole lot of water being lost if the feed tube breaks somewhere.
 

texasmax

Well-known member
May 24, 2010
118
Dallas, TX
#6
Right- and that's why I've got the leak at the outlet- because it can't get past the pinched pump tube. Should the check valve stop ALL flow, or just most of it? Maybe I'm thinking about this the wrong way- yes there's some mechanical breakdown in the outlet feed tube/ferrule- I'm thinking it's caused by the reverse flow getting past the injector check valve- even if I fix the feed tube/ferrule, it's going to happen again- and if it's pushing back hard enough to do that damage (even slowly over time), it's a fight between the stenner pump pushing bleach and the leakage coming backwards. Yes, all my problems go away if I limit the high-speed usage (which I do) and only push bleach on low speed (which I will do). But, fundamentally, should I have backflow coming out of the injector on high speed? Is that normal?
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,815
SouthWest Alabama
#7
My impression was that you had a leak with the tubing still hooked up. If that's correct, then there's a leak that needs to be fixed. You should not have a leak at all when the tubing is hooked up. If I misread your meaning, sorry bout that.

As for having a little liquid coming out of the tubing when it's disconnected that's normal as long as it's more drips than a full flow. The check valve used in the injection fittings aren't 100% seal-off. They let a little by at times.
 

texasmax

Well-known member
May 24, 2010
118
Dallas, TX
#8
There is a leak when it's all hooked up. But the part about the check valves in the injectors not being 100% answers the question! So my action plan is repair the leak, and only run the stenner when the pool pump is on low speed. Thank you!
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,815
SouthWest Alabama
#9
You should be able run the Stenner with the pump on high speed without any problem. I did it for several years before I got a 2-speed pump.

Do you have the low pressure or high pressure model? Since you have the #2 tube it's rated for 100PSI so the only difference between the low and high pressure models of the 10gpd pump is the low pressure comes with the injection fitting and the high pressure model comes with the check valve injection fitting.
 

texasmax

Well-known member
May 24, 2010
118
Dallas, TX
#10
Iv'e got the high pressure with the check valve-equipped injector (45MPHP10 Single Head Fixed Output). Agreed, makes sense that without any leaks the stenner should out-pump any reverse flow I've got going on. Been running it since 2014 and this is the first maintenance/repair outside of regular replacement of the pump tube.
 

gary300

LifeTime Supporter
Dec 15, 2014
499
Riverside California
#11
Do you have clear tubing or black tubing? The clear tubing is not UV resistant and will not last long with any direct sunlight. In any event, 4 years without replacing the tubing is a very long time in my humble opinion. I replace ALL of my tubing including ferrules every 2 years (including the pickup tube and strainer in the tank), and have never had a leak even when running my 3 Hp VSP pump at full speed.
 

texasmax

Well-known member
May 24, 2010
118
Dallas, TX
#12
Black. It's in a spot where it never gets direct sunlight. Now that you mention it, I have replaced the strainer assembly as well. But never any tubing or ferrules. Guess it's
 

rphpool

Well-known member
Mar 4, 2015
454
Sugar Land , TX
#13
My Stenner tubes go out once a year almost to the date. The #2 tube becomes hard and will not outflow correct amount of bleach. If I am not mistaken the new tube comes with new ferrules which I replace also. I to have a VSP and have no leak problems at any speeds. I do clean out my pickup strainer and blow out the black tubing once per year to get all the salt buildup out.