SWG output: Discussion on Cell Cycle times vs. Scheduled run times

[BMerrill]

Just a clarification and something to consider. Cell cycle time vs. actual runtime and output.

For example take the Hayward t-cells. They have a cycle of 180 minutes.
Output is set in percentage of the cycle, and starts at the beginning of the cycle.
At 50% the cell will be on for the first 90 minutes of the cycle and off the remainder 90 minutes of the cycle.
This continues until the scheduled operating time expires.

What happens when the operational runtime is set in increments less than a complete cycle still using 50% output of the cycle time.
For a 60 minute runtime the cell is on all 60 minutes= true output is 100%
For a 90 minutes runtime the cell is on all 90 minutes= true output is 100%
For a 120 minutes runtime the cell is on for 90 minutes = true output is 75%
For a 150 minutes runtime the cell is on for 90 minutes = true output is 60%
For a 180 minutes runtime the cell is on for 90 minutes = true output is 50%

Pool Math's suggested SWG runtimes do not account for this. Not sure it makes a huge difference at the end of a swim day.

 

[Newdude]

All cells need at least 1 cycles worth of runtime for the % output to be properly met. As you noted, for most cells with 100+ minute cycles, you would get more than you'd expect running the cell for an hour or less

Pentair has a 5 min cycle and Jandy Aquapure Ei has a 10 minute cycle and wouldn't be affected.

 

[Mdragger88]

I am not sure about this -
Or if it really matters for normal longer run times which are almost always longer than 180 minutes for most people.
I do know this - my new pureline t15 replacement cell output is exactly as stated in poolmath for my pool volume/%/runtime so far. This may be because I run it solid all day so those differences you mentioned don’t really come into play.

 

[Jimrahbe]

B,

I think in the big picture it does not really matter.

Sitting down and calculating it all out is great for the engineering minded, but in real life you just need to adjust the SWCG so that you can maintain the amount of FC you want in your pool.

It is not even close to an exact number. On a cloudy day you might make too much and on a really sunny day you might make too little. More swimmers, or less swimmers, auto cover on or off.. etc.

Too much work for me.

I just set the cell so that so that on an average day I stay pretty close to my target FC or higher. Then I just go swim.

Thanks,

Jim R.

 

[jgofnj]

Just a clarification and something to consider. Cell cycle time vs. actual runtime and output.

For example take the Hayward t-cells. They have a cycle of 180 minutes.
Output is set in percentage of the cycle, and starts at the beginning of the cycle.
At 50% the cell will be on for the first 90 minutes of the cycle and off the remainder 90 minutes of the cycle.
This continues until the scheduled operating time expires.

What happens when the operational runtime is set in increments less than a complete cycle still using 50% output of the cycle time.
For a 60 minute runtime the cell is on all 60 minutes= true output is 100%
For a 90 minutes runtime the cell is on all 90 minutes= true output is 100%
For a 120 minutes runtime the cell is on for 90 minutes = true output is 75%
For a 150 minutes runtime the cell is on for 90 minutes = true output is 60%
For a 180 minutes runtime the cell is on for 90 minutes = true output is 50%

Pool Math's suggested SWG runtimes do not account for this. Not sure it makes a huge difference at the end of a swim day.

But running for 60 min at 100% true output is not the same out as running it for 90 minutes at 100% true output. You produce less chlorine if running for just 60 mins vs running for 90 minutes. so you are not getting "true output" of 100% of a full cycle.

 

[BDY]

It would be fixed by running your pump
For at least as long as a full cycle or multiples thereof, no?

Like others here, I run 24/7 so i don’t have that headache, but if the cycle is 100 min the pump time should be 100, 200, 300 etc?

If you want to do the math on paper that way vs just testing the pool until you get your sweet spot dialed in?