# Thread: Considering a Stenner - Math and Insertion point check

1. ## Considering a Stenner - Math and Insertion point check

I'm still new to this whole pool thing in general, but looking to minimize the amount of work my wife will need to do daily. I'm still trying to convince her on the TFPC method, but she's getting there...

Anyway, I have an opportunity to grab a Stenner 45M5 at an absolute steal. It's adjustable out from 2.5-50 GPD. I think Pool Math and other things I've read here is telling me that in an ideal world, I'd need about 30-45 oz of 12.5% per day to maintain proper levels. At the Stenner's lowest setting, that would only need 2.25 - 3.5 hours of run time per day. I'd like to maintain the pump control mostly independent of chemical injection

Here's the question:How big of a deal is it to have water circulating while injection is happening? I think I'd plumb the Stenner to inject somewhere on the return line with proper backflow preventers and wire it to a standalone timer. I imagine it would have enough pressure to send the chlorine onward to the pool (1x 1.5" at the equipment pad to 2x 1.5" - tee'd underground somewhere) but I'm just unsure how important it is to be mixing such a low concentration as its entering. I suppose the other option would be standalone timer --> relay/contactor --> Stenner where the output of the contactor could close the 3-way switch point on my pump timer.

Thoughts?

2. ## Re: Considering a Stenner - Math and Insertion point check

Short occasional periods of the Stenner running without the pump are not a problem. But doing that routinely will eventually cause problems. The chlorine concentration will get very high in the pipe, and if that reaches the pool it could cause damage.

One good thing to do is to gate the Stenner power through both the pump timer and it's own timer, assuming the voltage is compatible. If they are different voltages you can do the same thing with a relay. The timers will normally stay in sync and if they get out of sync you won't get any chlorine and will need to put them back in sync.

There are other options, though they start to depend on more details of your setup than you have mentioned.

3. ## Re: Considering a Stenner - Math and Insertion point check

My down and dirty pool automation system consists of a pair of Insteon outdoor modules and an ISY994i controller. I use one module to run the main pump and the other to run the injection pump. I have a program that checks to see if the main pump is running before allowing the injection pump to run. The main pump is set to run a couple of hours 4 times per day and the injection pump is set to run during the first main pump run and then again a few minutes during a second main pump run. I use that system partly because I already have a good many Insteon devices and because I can program the modules to operate down to seconds if needed.

If you already have a home automation system(Insteon, Z-wave, etc.), you can probably find modules that will allow you to do something similar.

4. ## Re: Considering a Stenner - Math and Insertion point check

Originally Posted by Bama Rambler
If you already have a home automation system(Insteon, Z-wave, etc.), you can probably find modules that will allow you to do something similar.
I do have some Insteon gear - but definitely nothing that sophisticated at this point. Just the Hub, thermostat, and some lamp modules. I did look around for some outdoor modules to run the pump, but couldn't find anything outdoor rated for 120V.

At this point, I'm leaning towards two independent timers. I'll add a program for the main pump to go in the late evening/early morning for a few hours and make sure the Stenner run-time is well inside of that window. If that becomes too much of a hassle to keep in-sync, I can always add a relay on the Stenner timer to call for the main pump as well. I really wasn't quite ready to go down this road yet, but the Stenner being sub-\$100 makes it too hard to pass up!

Thanks for the input!

5. ## Re: Considering a Stenner - Math and Insertion point check

Search for Insteon outdoor modules (2634-222). They're rated for 15 amps and outdoor use.

I don't have the Insteon hub but I think you could control them with it.

6. ## Re: Considering a Stenner - Math and Insertion point check

Intermatic 3 circuit timer will do what you want methinks P1353ME
http://www.intermatic.com/en/Products/Pool_and_Spa/Electronic_Controls/Electronic_Timer_Mechanisms/P1000ME_Series/P1353ME.aspx.

7. ## Re: Considering a Stenner - Math and Insertion point check

The 45M5 is on the way. I think for now I'm going to just grab this \$20 outdoor digital timer and set it to run while the pump timer is running. I'm already way over budget on the rest of the startup equipment and mechanicals. Since I bought this secondhand, all I'm receiving is the pump itself - so I'm going to need to source some tubing and fittings. From what I can tell, it's all standard sized stuff, right? If so, I would assume irrigation type/UV tubing will do the job and I can grab that from any local store.

I'd like to tee it in to the plumbing somewhere post-heater - I think the easiest spot to splice in to is the vertical portion just before the CL200 chlorinator. The other (easier) idea I had was to use the drain plug of the CL200. Any downside to that?

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