Auto pilot nano plus with Rc 28

[guytimes]

I have an Auto pilot nano plus with Rc 28 on my 13K gallon fiberglass pool. This is the third year for the unit. At the end of last year, I noticed I had to bump up the % to keep the chlorine level up enough.

This spring, I soaked the RC-28 in sw generator cleaner, even though I could not see any build up on the plates. After "slamming" my pool a few weeks ago, the chlorine level dropped all the way to zero, even though I'm running the SWG at 100% for 10 hours a day.

I was about to order a new RC-28 unit and realized they are around $400! What should I do to troubleshoot? I can't tell if it's making any chlorine at all. I have to add bleach every few days to keep the FC up. Should I test the voltage at the unit?

Thanks
TOm

 

[needsajet]

Nice to meet you via TFP

You can test if the SWC is working by using an eye-dropper or pipette pushed inside a return jet to collect a sample. With the SWC running (i.e. bubbles coming up from the return), collect the sample and the water should have higher FC than the pool water. Doing this on low speed is a more effective comparison.

The other thing to do is to raise your FC to your target level with chlorinating liquid, and then see if the SWC is able to maintain the level.

An Overnight Chlorine Loss Test is your best bet to rule out algae consuming too much FC for your SWC to keep up. A lot of little kids (or big kids) swimming will also consume a lot of chlorine, especially if they didn't go to the bathroom before swimming.

If the SWC is not generating chlorine then yep, it's time for a new cell, and yes they do deplete but usually more like 4 to 7 years. Note that cleaning the cell should be avoided unless there's visible scale buildup. Each cleaning will shorten the cell's lifespan.

 

[GaryT58]

+1 on needsajet suggestions. Also, please post your current pool chemistry - FC. TC, PH, TA, CY. For example if you have little or no CYN, then the sun will break down your FC very quickly. A SWG is great for maintaining FC if the CYN is in a good range, is sized correctly, and the FC was in optimum range to start. It is not good, unless majorly over-sized to slam, or raise FC from 0 quickly (or at all).

Finally, you can find the replacement cells for much less. You can PM me if you want for details.

 

[guytimes]

Hey guys thanks for the tips. I collected some water coming out and the FC is higher than the water in the pool. Turns out my CYA was down to around 40 which is pretty low I think. I added more stabilizer. Maybe the chlorine is burning up faster than the SWG is making it.

Looks like this was user error. Thanks again.

Tom

 

[JoshU]

Should I test the voltage at the unit?

Just for future reference you'll always want to test the cell/system through the "Test Pool Pilot" menu and only while boost mode is activated.

I was about to order a new RC-28 unit and realized they are around $400!

Be sure to go through an authorized dealer and you'll get a $50 mail-in rebate when purchasing a new cell.

 

[guytimes]

It's me again, I've been meaning to post. Shortly after my last post back in may, I boosted my stabilizer up between 70-80. It's still around 70. For the last 2.5 months I have been running my Digital nano plus at 100%.

I have been struggling all summer to keep the FC around 1, sometimes it's not even that, and I've been adding a gallon of bleach about every two weeks, just to bump it up a tad. The FC coming out of the cell is around 1.5 (when I turn the flowrate down on the pump). At normal speed, it's about .5-1. Yesterday I took the cell out again, and soaked it in a muratic acid / water solution of 1-4, for about 2 hours. Re-installed it, absolutely no difference. FWIW, when I look at the fins inside the cell, the look clean. I can't see any build up on them. I even bumped the salt up to 4500 and it doesn't help. Seems so crazy as my pool is 14k gallons and this thing is rated for 28K gallons.

I'm having a hard time believing there is something wrong with this cell. It's not even 2.5 years old. I hate to spend $369 on a new one and a chance it doesn't fix the problem. I've scoured around to troubleshooting steps but all I can find are the "end user" type dummy troubleshooting steps. If I call the pool man, he'll charge me a lot of money and most likely send a kid out who knows less than me about it.

The system worked great the first summer (may - Sept) and produced plenty of chlorine when the unit was set at about 20%, running 10 hours a day. The second summer (last summer) it worked fine until about the end of the summer I noticed it couldn't keep up.

Is there anything you can think of that would make the system run less efficiently than it should, other than a dirty cell?

In other words, is there something I can check before I spend the money on the cell?

Tom

 

[mknauss]

Did you ever do a Overnight Chlorine Loss Test?

 

[ping]

Put the TF-100 to use and let us know how the OCLT turns out. Your pool most likely has nascent algae that is consuming the chlorine as it is made. The OCLT will confirm this if the pool fails the OCLT.

Every time you clean the cell with acid it takes off the coating on the plates inside the cell and reduces the life of the cell. If it is clean then don't clean it.

 

[guytimes]

It's been since may when I did the OCLT test but yes I will do it again tonight and find out. Maybe something snuck in after my slam process back in late April.

Meanwhile, if anyone can, will you test the water coming out of your chlorine gen and let me know what it is. I wish I would have tested it a long time ago so I could know if 1ppm is normal or not.

 

[needsajet]

I think your cell is fine and it's algae, but with my smaller pump, and on low speed I get about a 2 ppm difference between return jet water and pool water (e.g. 7 ppm vs. 5 ppm). I sample from the closest return, when there's bubbles coming out, with a disposable pipette inserted well into the return jet. I draw 2 mls at a time until I have 10 mls.