Stenner GPD tolerance question

[Chasarms]

Question for those using a Stenner:

What is your experience with the GPD specs on these pumps?

Today, I installed a Stenner 8.5 GPD Econ T. Unfortunately I had issues with getting the correct fittings to finish, but I did get it mounted and have the tank in place.

My pump is rated at 8.5 GPD. So, if I do the math right, I expected the pump to deliver about 16 oz of chlorine in 22 minutes. I did a test run and the pump, and it delivered about 21 oz of fluid in 22 minutes. I set it up to pump into a measured container.

The one variable is that it was pumping through an open tube, as I did not install the injection port on the tubing.

To anyone with experience, would the open tubing allow that much more flow?

 

[elier99]

I currently have a 12.3GPD stenner pump with a rated 1.09 oz per minute. The measured flow rate was 0.99 oz per minute, slightly lower rate as specified. Because of the way a peristaltic pump operates I would not expect a flow increase when the injector is disconnected.

 

[rphpool]

I wondered same thing as I have seen the same results. Could it be that the amount per day,hour,minute is at the outlet of the unit. Could it be the length of the tubing to the return line has some chlorine in it still. I don't think so since the tubing should always have chlorine in it after every run. Curious though. That is why I dial mine in by FC results for the time I have the Stenner pump running. Also I have been keeping a log for the past 4+ years of when I change the run times on my Stenner. It is June and hot now in Houston area so yesterday I had to crank up the Stenner run time to get the FC I am looking for. Good Luck

 

[Chasarms]

I currently have a 12.3GPD stenner pump with a rated 1.09 oz per minute. The measured flow rate was 0.99 oz per minute, slightly lower rate as specified. Because of the way a peristaltic pump operates I would not expect a flow increase when the injector is disconnected.

Thank you for the reply. Stenner tech support affirmed your thought that the port injector would not impact the flow. He advised me to try the other tube to see if the performance was more in spec. I don't think I will do that though. I am just going to run a few more tests to see if it is consistent. If so, I will just adjust delivery times accordingly. I don't see any reason to waste a tube that I can use next year. But, I will have to remember to test again when I change it.

 

[Chasarms]

I wondered same thing as I have seen the same results. Could it be that the amount per day,hour,minute is at the outlet of the unit. Could it be the length of the tubing to the return line has some chlorine in it still. I don't think so since the tubing should always have chlorine in it after every run. Curious though. That is why I dial mine in by FC results for the time I have the Stenner pump running. Also I have been keeping a log for the past 4+ years of when I change the run times on my Stenner. It is June and hot now in Houston area so yesterday I had to crank up the Stenner run time to get the FC I am looking for. Good Luck

I am only using about 3 feet of tubing. I just can't see a tube that small holding 5 oz of fluid. Plus, as you noted, the tube remains pinched off by the roller when it turns off. It shouldn't allow very much fluid to leak out, if any. I don't really have any issue with it being that far out of spec as long as it is consistent. I'll just recalculate the run times accordingly.

 

[Chasarms]

I ran two more tests today with the same results. Interesting that the pump would be so far out of spec. Again, it doesn’t impact the application of it, but it should remind anyone considering one to test the actual output and not set the dosing based on the published rating.

 

[GP2]

My 22gpd was pretty close so I use the spec rate for now, but figure that could change over time or when I replace the tube and may need to change the rate, so thanks for the good reminder!
The spreadsheet I use combines a few useful calculators and comments I’ve seen here on how people are testing and tracking - you can select to use spec rate for fixed or Econ pump models, measured rate, or a “calibrated“ rate. Setup tab has the pool and pump rate info, check impacts of..., FC vs runtime table. Enter storage tank info on tracking tab and track daily runtime, weekly averages and tank levels. Feel free to download if it’s helpful.
The link in my signature is a sheet with pump and tank info entered and Blank copy of the spreadsheet is here:

Stenner Tracking v0 - Blank Copy.xlsx

1drv.ms

 

[Chasarms]

My 22gpd was pretty close so I use the spec rate for now, but figure that could change over time or when I replace the tube and may need to change the rate, so thanks for the good reminder!
The spreadsheet I use combines a few useful calculators and comments I’ve seen here on how people are testing and tracking - you can select to use spec rate for fixed or Econ pump models, measured rate, or a “calibrated“ rate. Setup tab has the pool and pump rate info, check impacts of..., FC vs runtime table. Enter storage tank info on tracking tab and track daily runtime, weekly averages and tank levels. Feel free to download if it’s helpful.
The link in my signature is a sheet with pump and tank info entered and Blank copy of the spreadsheet is here:

Stenner Tracking v0 - Blank Copy.xlsx

1drv.ms

Cool. Thank you.

I’ll post my setup with some pics when my fittings arrive and it’s complete. Nothing special but I may have a wrinkle or two that folks are interested in.

 

[rphpool]

My 22gpd was pretty close so I use the spec rate for now, but figure that could change over time or when I replace the tube and may need to change the rate, so thanks for the good reminder!
The spreadsheet I use combines a few useful calculators and comments I’ve seen here on how people are testing and tracking - you can select to use spec rate for fixed or Econ pump models, measured rate, or a “calibrated“ rate. Setup tab has the pool and pump rate info, check impacts of..., FC vs runtime table. Enter storage tank info on tracking tab and track daily runtime, weekly averages and tank levels. Feel free to download if it’s helpful.
The link in my signature is a sheet with pump and tank info entered and Blank copy of the spreadsheet is here:

Stenner Tracking v0 - Blank Copy.xlsx

1drv.ms

I was trying to use your file but it will only open in "read view". Can you re post so I can input my pool numbers. Thanks for the hard work, will come in handy

 

[Chasarms]

I was trying to use your file but it will only open in "read view". Can you re post so I can input my pool numbers. Thanks for the hard work, will come in handy

I had to download the file to my PC and work on the local copy.

 

[Iam1964]

I have a 10 gpd model but it has consistently produced 12.1 gpd for the last 5 months. Not really a problem as long as you do a check every so often.

 

[GDN]

I've got a 10 gpd pump. My key was to use water to see what the pump truly pumped before adding the chlorine. I tested using 8 and 16 ounces of water. Calculations say it should pump .89 ounces a minute and in reality my testing shows I got 1.2 ounces per minute. I used that number for my starting place for how long to pump chlorine every day based on pool size, then adjusted and fine tuned it based on actual water testing.

As the summer winds down I just adjust the timer every month or two. I add a little chlorine every day even over winter, then dial it back up as them temps rise.