What is a SWG rest cycle?

[setsailsoon]

Folks,

I'm starting to make adjustments to my run time and % output on my new Circupool RJ 30+. My FC seems to go up rapidly so I drop the output to 25% from 50% and I reduce the run time to 6 hrs. After running for about 2 hrs I check the unit and the readings are all "0". No salinity, Percent Output, amps - nothing! So I took to the trouble shooting and find there's a reference to "rest periods" during which the unit just stops producing and measuring. Does anybody know what these rest periods are for? Do all SWG's do this?

Chris

 

[Jimrahbe]

Chris,

The percent of output on a SWCG does not work like the volume on a radio where you actually adjust output in a linear fashion..

Basically, if you set the output to 50% and the cell will only produce chlorine for 50% of the time it is on... On my Pentair IC40, the cell is on for five minutes and off for five minutes and then on again for 5 minutes... etc... The time it is off is called the rest period...

Not all cells have the same cycle time and I do not know the exact cycle time for your RJ-30...

But, as far as I know all American cells work this same basic way...

Thanks,

Jim R.

 

[ajw22]

Changing % and pump run time is changing two variables and makes it hard to dial in your SWG. Change one or the other.

If CL is climbing then reduce % 10% or pump runtime by an hour. Wait a day and check FC. Repeat until you find the settings where FC stays steady. As the days get longer you will have to increase the SWG output.

Once you find the stable FC setting then if your FC is too high reduce the % another 10% and let the FC drift down. It may take a few days. Then increase the % back up.

Be patient. It can take a week or more to dial in the SWG.

Keep in mind too high FC is always better then loo low FC.

 

[setsailsoon]

Jim and Allen, thanks for the replies. I guess I read in the manual that the current through the cell would range from a little over 2 up to 8 amps and I inferred that was controlled by the % setting. Now I notice that it runs pretty constant at 4.78 amps no matter what the % setting is. Guess this is more a function of the salinity and condition of the cell? So within each cycle there must be the on-off cycle Jim mentioned. In addition there appears to be a "clean" cycle where the amperage goes negative. These things are a little more complicated than I thought. The instructions say to start at 70%, I started at 50% and my FC went up by 3 in just a few hours. I'm sort of doing what Allen suggested with the goal of getting the lowest % within the normal run time on my pump. I've made two adjustments down to 25% and it looks like I'm getting close. Now I'm tweaking run time (currently 5 1/2 hrs). I'm already loving no more trips to Leslie's for liquid chlorine. All I add now is MA and that's stayed about the same amount as before the SWG. Next step is to add borax to make pH adjustments less frequent.

Another question I have is stability. I've operated a lot of catalytic reactors in the chemical industry. Usually activity is super high to start then it rapidly declines and levels off for a long time. Then at some point in the future activity drops like a rock and you have to regenerate or replace the catalyst. Is this how these cells work or do the settings stay pretty much the same?

A couple of people on this site recommended SWG for me a while back... wish I had listened back then. This is way easier. Not to mention how much better the pool water feels.

Thanks again for the replies.

Chris

 

[Jimrahbe]

Chris,

The cell will have a fairly stable output until it uses up the amount of chlorine it can generate, it will then fall off pretty quickly..

What will not be stable is the amount of FC your pool requires.. As you most likely know from your jug dumping days, the weather and the time of year, will change the amount of FC your pool uses each day.

You can drive yourself crazy trying to adjust the SWCG to keep up with day to day changes... I find it works best for me, to run my FC a little on the high side, just so that I never have to worry about any daily changes.. I still of course have to adjust up as the Summer gets here and then down again in the Fall.

We tried to tell you how great a SWCG would be, but you just would not listen...

Thanks,

Jim R.

 

[JoyfulNoise]

I would not suggest you use borax to add borates but rather purchase boric acid from Duda Diesel online and use that instead. If you use Borax (20 Mule Team Borax), you will also need to add lots of acid along with it to offset the caustic nature of the sodium pentaborate. Boric acid, by contrast, is a weak acid that has only marginal effects on pH when added to water. If you look at the cost of each product, they are roughly the same (depending on shipping rates and availability) BUT it is A LOT easier to add boric acid to water since you can pretty much do it all in one shot whereas borax requires breaking the additions up into batches in order to keep the pH from spiking.

 

[jstephens1]

Duda Diesel is great, just re-ordered my boric acid

 

[Fuldo]

I installed a RJ-30 about a month ago and started a thread about the same subject. I learned a lot since, most from responses from that post, discussions with the supplier and with my experimentation with it since.

In a nut-shell, the RJs run a "200 minute cycle" and are full-on or full-off. Every time the system is powered-up it starts a new cycle. If the output is set to 10% then the cell will be driven for 20 minutes, then off for 180 minutes. If left on it will then run another 20 minutes with a reversed polarity with another 180 minute rest period. This will continue until power is removed or the unit itself is turned off. This assumes that the water temp and salinity readings are within acceptable operating range. 20% output would be 40 minutes on and 160 off. Most readings are properly displayed only when the cell is active. I found the low temperature limit to be about 57 degrees F. I also found that the salinity shown is about 300 lower than what the concentration actually is so it's best not to let the actual salinity drop to less than 3400 or so to give some margin on the 2800 lower limit that the RJ needs to measure.

If the pump and SWG are running for long periods then the percentage of minutes with cell power are about what is set for output percentage. The problem becomes when pump time is very low. A 4 hour (240 minute) pump cycle with the output set to 10% with result in 20 minutes on, 180 minutes off, 20 minutes on then 20 minutes off to complete the 240 minute period. That means the actual average output is 40/240=17%, not the 10% expected. I've gotten to point that I track actual cell on-time per day and adjust that based on changing pool needs by using a combination of pump time and output setting. For instance, I recently changed from 4 hours at 20% to 8 hours at 15%, that 4 hour period had cell power for 80 minutes total and that 8 hour period has cell power for 90 minutes.

That said, I'm with Jim R on maintaining FC level somewhat higher than needed so day-to-day changes aren't required and only occasional changes are required as the weather changes during the year. The other thing I've noticed was that normal maintenance often requires the pump to be stopped for a short period and restarting will start the cycle over again and result in additional unplanned on-time.

 

[setsailsoon]

Chris,

The cell will have a fairly stable output until it uses up the amount of chlorine it can generate, it will then fall off pretty quickly..

What will not be stable is the amount of FC your pool requires.. As you most likely know from your jug dumping days, the weather and the time of year, will change the amount of FC your pool uses each day.

You can drive yourself crazy trying to adjust the SWCG to keep up with day to day changes... I find it works best for me, to run my FC a little on the high side, just so that I never have to worry about any daily changes.. I still of course have to adjust up as the Summer gets here and then down again in the Fall.

We tried to tell you how great a SWCG would be, but you just would not listen...

Thanks,

Jim R.

Jim,

Yep, I remember you telling me that... but I'm famous for not listening... just ask my wife! I almost didn't even get the pool but she persevered and now I use it waaay more than she does. Best thing we did on the house was the pool and enclosure.

I got my replacement tail-pieces yesterday and redid the PVC parts I had to bend. Looks really nice now. And seals up by hand tightening the unions. I just need to cover and clean up the wiring now.

Thanks for the tips on FC. I'll ease into this just the way you describe. Seems like we don't notice the FC all the way up to 9 ppm in salt water. Prior it would cause irritation on my wife so I had to watch it pretty closely. Luckily I was down to just 2 full and 2 empty jugs of chlorine. Guess they are good to keep on-hand.

Chris

 

[setsailsoon]

I would not suggest you use borax to add borates but rather purchase boric acid from Duda Diesel online and use that instead. If you use Borax (20 Mule Team Borax), you will also need to add lots of acid along with it to offset the caustic nature of the sodium pentaborate. Boric acid, by contrast, is a weak acid that has only marginal effects on pH when added to water. If you look at the cost of each product, they are roughly the same (depending on shipping rates and availability) BUT it is A LOT easier to add boric acid to water since you can pretty much do it all in one shot whereas borax requires breaking the additions up into batches in order to keep the pH from spiking.

Matt,

I'm turning over a new leaf and listening for a change. This sounds a lot easier. I'll see if I can get my order in today then add next week.

Thanks for the advice.

Chris

 

[setsailsoon]

I installed a RJ-30 about a month ago and started a thread about the same subject. I learned a lot since, most from responses from that post, discussions with the supplier and with my experimentation with it since.

In a nut-shell, the RJs run a "200 minute cycle" and are full-on or full-off. Every time the system is powered-up it starts a new cycle. If the output is set to 10% then the cell will be driven for 20 minutes, then off for 180 minutes. If left on it will then run another 20 minutes with a reversed polarity with another 180 minute rest period. This will continue until power is removed or the unit itself is turned off. This assumes that the water temp and salinity readings are within acceptable operating range. 20% output would be 40 minutes on and 160 off. Most readings are properly displayed only when the cell is active. I found the low temperature limit to be about 57 degrees F. I also found that the salinity shown is about 300 lower than what the concentration actually is so it's best not to let the actual salinity drop to less than 3400 or so to give some margin on the 2800 lower limit that the RJ needs to measure.

If the pump and SWG are running for long periods then the percentage of minutes with cell power are about what is set for output percentage. The problem becomes when pump time is very low. A 4 hour (240 minute) pump cycle with the output set to 10% with result in 20 minutes on, 180 minutes off, 20 minutes on then 20 minutes off to complete the 240 minute period. That means the actual average output is 40/240=17%, not the 10% expected. I've gotten to point that I track actual cell on-time per day and adjust that based on changing pool needs by using a combination of pump time and output setting. For instance, I recently changed from 4 hours at 20% to 8 hours at 15%, that 4 hour period had cell power for 80 minutes total and that 8 hour period has cell power for 90 minutes.

That said, I'm with Jim R on maintaining FC level somewhat higher than needed so day-to-day changes aren't required and only occasional changes are required as the weather changes during the year. The other thing I've noticed was that normal maintenance often requires the pump to be stopped for a short period and restarting will start the cycle over again and result in additional unplanned on-time.

Naldo,

Very helpful information! Wonder what made them thing of a 200 minute cycle? Knowing this will probably avoid some frustration so thanks very much! I think I'm pretty close to finding the % run time that allows me to tweak the run time of the unit to keep FC in range. It's easier for me to do it this way since I have it on-off controlled by my automation using an idle relay.

Chris

 

[Fuldo]

I suspect the 200 minute cycle time has to do with the IC and programming used, it was probably just less expensive and easier. I've since learned that most SWG systems have a much shorter cycle time, the Pentair is very short so it's much more "accurate".

 

[Jimrahbe]

I have no idea what the actual cycle time for the RJ-30 is, so take what I say with a grain of salt (pun intended... )

There are normally two times associated with salt cells.. One is the cycle time between polarity changes.. this is normally measured in hours like two, three or four hours.. The other cycle time is run vs rest time... 200 minutes sounds much more like the interval between polarity changes to me..

From a engineering perspective it is hard for me to believe that they would design something that operates using such a long period between cycles..

Does the RJ series have a light or some way to tell when it is generating chlorine? Has anyone actually watched the indicators to confirm the actual on time vs the off time?

I'm not saying 200 minutes is not correct, but that on the surface it just does not make any obvious sense to me...

Thanks,

Jim R.

 

[Fuldo]

The RJ controller has a "Generate" LED light on the control panel that lights when the cell is active. This can be confirmed by looking at the cell current on the menu; the operating current will be displayed when the generate indicator is on but current is shown as zero when that light is off. I've monitored the performance of the system at both 10% and 20% and confirmed the 20 on/180 off and 40 on/160 off cycles. I didn't stand at the controller for hours with a stop watch but checked it every few minutes and watched it closely at the expected "switch" time and I'm convinced the system operates as I've been told by more than one source including discount salt pool who appears to be the only supplier of these devices. From my observations I also believe the polarity changes at the end of each 200 minute cycle.

I did some research on who actually designs and manufactures this brand hoping to talk to a factory person but I wasn't able to find any definite information on the manufacturer. It seems the manufacturer is somehow tied to discount salt pool but they wouldn't give me any details. My guess is that the hardware is made by an overseas manufacturer and maybe imported by discount salt pool but that's just speculation on my part. If anyone knows more of the origin of this product I'd love to hear it.

I only have experience with this CircuPool RJ-30 unit and my daughter's Pentair IC-40. I haven't tried to observe the IC-40 cycle times but I'm told they are very short and that would be an advantage in my opinion. I've only had the RJ-30 for about 6 weeks and it has performed perfectly but I do wish the cycle time was shorter and I wonder about reliability going forward. The system was a great value and I hope it proves reliable. Mine is sized about 3X so I'd expect it to last many years.

 

[Jimrahbe]

F,

Thanks for the feedback.. As long as the owner understands the cycle times, then I don't see a problem. But if you did not understand the cycle times, I could see how it could lead to all kinds of confusion... It would almost be better to run at 100% and control the time the cell was on with a timer.. At least then you'd know exactly the time the cell was on without any calculations and cycle time issues.

Not how I would have designed it, but I guess that is why I don't make the big bucks...

Thanks again,

Jim R.