troublshooting intellichlor output, technical advice? always low FC

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Z

Zzz

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May 15, 2013
6
Dix Hills, NY
I have approximately 38,000 gal in-ground plaster pool and I'm struggling to maintain a decent FC level with an IC40.
I originally had a Hayward aquarite with T15 cell with 1 hp pump at 8 hrs /day and FC levels were always good at around 3-4 PPM
I ripped that system out and renovated with Pentair EZtouch with built in IC40, intelliflow VF, and intellichem and screenlogic. I set up pump to run low flow 23 hrs/day for 1 complete turnover and set intellichem to run the SWG for 12 hrs/day. Water was balanced, salt 3200, CH 340, TA 70, PH 7.6, CYA 30. FC would never be over 1 PPM unless I shocked. Walls would green up if I didn't shock. Increasing the SWG runtime to 23 hrs/day helped a little but the FC should be much higher. ORP always read low around 500 but that's from the SWG effect. The longer I ran the SWG, the lower the ORP reading on the intellichem.
I just chalked it up to the sun destroying the FC due to low CYA required for the intellichem to "work accurately" (which it didn't).

This year I decided to experiment a little. I dissolved 25 lbs of CYA (first mistake) before measuring existing CYA. I wanted to see if the FC would improve its longevity with a higher CYA. So now I'm between 90-100 ppm CYA which made the intellichem useless. the ORP reads at over 1000 with zero FC in the water. At that level the SWG will not dose at all. My new FC target with this much CYA is now 5 PPM. I removed control of SWG from intellichem and now have % control from eztouch. I set to 100% @23 hrs/day and let it run. After 4 days the fc was at 1.2 PPM. I am stumped at this point. I wait for night to shock the pool. Here is where it gets interesting.

I turned on the pool light so I can see what I'm doing and there a jet right above the light spewing a milky cloud of bubbles which is normal SWG output. Suddenly it decreases to a few and then no bubbles. I check the IC40 and the output lights are still on at 100% all systems go. The bubble stream came back about 5 1/2 minutes later and made bubbles for 4 minutes and stopped again for another extended period if time. No status change on the IC 40 panel. This cycle repeats constantly so 100 % output is not continuous. It is more like 40%. This could have been my problem all along. Anyone familiar with this problem and how to diagnose?
 
It sounds more to me that you have an algae problem coupled with a salt cell that's grossly undersized for your pool. SWGs are notorious for not being able to keep up when there is an algae bloom. Shut the SWG off overnight and do an OCLT. Report back with your results.

Bubbles from the returns don't necessarily mean that the cell is or isn't producing chlorine. There are a lot of things that happen within the cell, namely polarity reversal to somewhat self clean the cell. That may very well be what you were seeing when the bubbles stopped and not necessarily an indication of the cell acting up. The cell is just too small.

You are also likely experiencing the downfall of ORP. I'd suggest keeping the cell running off a % based cycle.
 
so that IC40 will have to run 24/7 just to keep up with your FC and you may still need to add bleach about once a week to stay above FC levels..
 
Agree with Brian. Sounds like you have algae that was never completely eradicated. I don't think the IC40 is grossly undersized as it's rated for 40k gallons, but probably right at it's limits and definitely can't keep up with a pool with an algae issue.
 
Let me chime in here, since I'm dealing with some IC-40 issues as well.
1. IC40 seems to be adequate for your 38K gal pool. From the IC40 manual:
IC40 Cell (P/N 520555): Designed for pools up to 40,000 U.S. gallons (150,000 liters). The cell will produce the equivalent of 1.40 lbs. of pure chlorine per 24 hours of continuous pool pump run time

2. You need to roll out any algae. Shut the SWG off overnight and do an OCLT. Report back with your overnight chlorine loss. Turn back SWG for 12 hours, measure chlorine loass again. It will give you accurate representation if chlorine is actually generated by IC40.

I personally think your IC40 is dead. Call Pentair support and let then replace your unit under warranty.
 
Ok here we are, the night of the original post I decided to shock the pool. pool calculator gave me shock level of 25 ppm based on my high CYA. I threw in 10 scoops of 73% hypo and checked it in an hour. FC was at 13.5 using a 10 ml sample size. Threw in another 10 scoops and went to bed. didn't bother measuring as I figured since I started at 0.8 ppm FC and 0.4 CC, the math tells me I should have reached target FC.

The next morning the FC was at 19.5 which would indicate a significant fc loss unless an overnight fc loss at those high reference levels might be caused by other factors, or maybe it was algae, I just don't know.

Ran the pump and chlorinator all day (very sunny) and in the evening using a 25 ml sample the FC was 8.6 and CC < 0.2 which is my new reference point for OCLT. I shut the intellichlor overnight and re measured in the morning. FC had dropped to 7.8. don't know why it dropped unless the shock didn't get all the algae or my sample sizes were flawed. I forgot to turn on chlorinator untill mid day sow I pretty much cant tell if the output is significant based on a short run time so I set up for another OCLT.

I measured night time FC at 7.8 twice to be sure and this morning at 7.6 twice again to be sure. Loss was 0.2 PPM. The pump was on the whole time for this test and including during the prior day overnight test . I don't know if circulation plays any part in chlorine loss, I just thought about it now. should the pump be off overnight as well for the test?

I remembered to turn on the chlorinator this morning and will measure after 12 hrs on a sunny day to see if chlorine can keep up. I'll post back later.


I did make additional observations about the IC 40. It definitely does cycle on and off when set to 100%. I used a dc voltmeter in the output board feeding the cell in the ez touch enclosure and a clamp-on ammeter on the transformer to measure the parameters. DC load voltage to cell is 35VDC and current draw is 5 amps for 4 1/2 minutes. This is when you see bubbles. Then the unit shuts off for 5 1/2 minutes where the current draw is 0 amps and the no load dc voltage climbs to 40 VDC and no bubbles from jet. This pattern repeats consistently and does not appear to be a malfunction.

It is not the polarity reversing cycle as the reverse cycle happens in a continuous 4 hour block per 24 hrs of run time and will produce chlorine bubbles while the polarity is reversed.

Thinking a little more about it, the on off time ratio makes the most sense, otherwise the super chlorinate function would be the same as leaving unit at 100%. What we are shown on the display of 100 % is around 40% actual duty cycle to the chlorinator. I will run the super chlorinate and see if the time ratio changes. I bet it does. In fact I'll be willing to bet that if the physical size and plate count of the IC20,40 and 60 are the same, its only the firmware (time ratio) that makes them different. Pentair already does this with the ez touch circuit board. The ez touch 4 board has all 8 buttons and 8 relay connectors just like the ez touch 8 but the firmware does not acknowledge them. this is the most efficient manufacturing process, make 1 item and use firmware to create several different models.

I cant believe I just hijacked my own thread. LOL

Brian, I do agree that the SWG capacity rating of running a pump 24 hrs just to produce chlorine is ridiculous. I calculated for 1 complete turnover and I run mine 24 hrs at 1200 rpm and 195 w for the energy savings and passing water slowly through a filter is always better. Another plus is the skimmers are always active and I get less debris sinking to the bottom. It is also dead quiet at that level.

I just checked out your pool build and Brian, You are the POOL MASTER. I know it was already said but "Theme Park" was the first thing that jumped into my mind. Great job.
 
Ran across this thread looking for help with my dead IC60.

I had exactly the same problem with my intellichlor which initially was an IC40. My pool installer, who I realize now really didn't know what he was doing and just wanted to move on to the next job, insisted, despite my research indicating the contrary, that the IC40 would be adequate for my 36000 gal pool. He put in the IC40. No chlorine. I was told to turn it up 10% every 3 days until I got an adequate chlorine reading in pool. I did that for about a week but was up to 60 % with zero reading. I turned it up to constant 100%- still zero reading. All cell lights were ok. He changed to a new IC40 cell thinking it defective- still zero chlorine in pool on 100%.

I insisted I needed an IC60 based on everything I read here and elsewhere on the web. He fought me on it but finally and reluctantly relented. He put in the IC60 kicking and screaming and left the equipment not seeing that flow was inadequate with a red flow light. I read in the installation instructions that came with the unit that Pentair recommended at least 18 inches of straightway pipe entering the inflow side of the intellichlor. He had a hair-pin turn directly entering it. I asked him to change the pipe configuration accordingly. He swore up and down that wasn't the reason for low flow. He was really po'd at me and came over, added the 18 inch straightaway and voila, normal flow. And, guess what, with the IC60 I immediately started to get chlorine readings in the pool and it has been fine since- for four years until it just died 2 weeks ago.

Sorry about the rant but as you can see, and I think reasonably so, I think my pool installer is a complete idiot and a jerk. I had to watch him very closely and I stopped him on a few occasions from making what would have been catastrophic irreversible errors with my pool installation.

But anyway, from what I have read and my own experience I think people with a pool larger than 30000 gal would be better served with an IC60. At the very least you will probably get longer life from the cell.
 

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Zzz said:
In fact I'll be willing to bet that if the physical size and plate count of the IC20,40 and 60 are the same, its only the firmware (time ratio) that makes them different. Pentair already does this with the ez touch circuit board. The ez touch 4 board has all 8 buttons and 8 relay connectors just like the ez touch 8 but the firmware does not acknowledge them. this is the most efficient manufacturing process, make 1 item and use firmware to create several different models.
Click to expand...

I just updated from an IC40 to a 60 [which I can't get to work now! ;-(]. There are more plates in the 60 than the 40. I will try to remember to take a photo of both, since they are both out of the circuit right now.
 
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