AutoPilot DIG-220 intermittently reads 0ppm salt

[lpaulriddle]

Hi,
I'm new to the forum. Glad I found it, looks like there's a lot of good info here.

I have a brand new AutoPilot Pool Pilot Digital (DIG-220) with an SC-60 cell, in service for a little over a month with no problems until this past weekend. On Saturday I noticed the red light was flashing and the display was showing low salt. The "test pool pilot" function showed 0ppm salt.

I killed power to the unit, unplugged and reconnected the tri-sensor cable at both ends, and started back up, and it started working again, so I assumed it was just a problem with the cable not being seated properly. However the problem came back the next day. It seems to be an intermittent thing; sometimes it will show the correct level on startup (actual salt concentration is 2800ppm per AquaChek test strip) but then a few minutes later it will read 0ppm. Occasionally it will read low salt (say 1500ppm) but the most common failure mode is 0ppm.

The other tri-sensor functions (temperature and flow) seem to be working normally.

I pulled the cell and the tri-sensor and inspected both; both appear completely clean. The unit works fine otherwise, but the frustrating thing is I never know when it's going to stop producing purifier because it thinks the salt is low.

I called the factory and they gave me an auth code for warranty service and the number of the nearest service center, so I can get someone out to look at it. But in the meantime I was wondering if anyone had seen this problem before. Is there anything I can test to try to narrow this down to a bad cable vs. bad tri-sensor vs. something else?

Also, considering that the system is working fine otherwise, and I know my salt concentration is OK, is there a way to bypass the salt test (with a jumper or something perhaps) so that the system will keep producing purifier until I can get the problem resolved?

The pool is a 22'x40' in-ground concrete, approx 35,000 gallons with a sand filter. Not sure if water chemistry has any bearing on this problem, but at last check my FC was 6.0 (shocked recently), pH 7.5, TA 80, hardness around 120, CYA 40, salt around 2800ppm as mentioned above. Water is clear with no visible problems.

Any insight would be greatly appreciated. Thanks!
Paul

 

[JasonLion]

Welcome to TFP!

That problem is almost always a bad cable, either a bad connection at one end or the other, a bad solder joint inside the connector, or a nick somewhere in the middle of the cable that causes an intermittent connection to the salt sensor. However, it is possible for it to be a main logic board problem or a tri-sensor problem. Both of those are much less likely, but difficult to rule out. The intermittent nature of the problem will make it more difficult to debug.

 

[lpaulriddle]

Welcome to TFP!

That problem is almost always a bad cable, either a bad connection at one end or the other, a bad solder joint inside the connector, or a nick somewhere in the middle of the cable that causes an intermittent connection to the salt sensor. However, it is possible for it to be a main logic board problem or a tri-sensor problem. Both of those are much less likely, but difficult to rule out. The intermittent nature of the problem will make it more difficult to debug.

Thanks for the reply. A cable/connection problem definitely makes sense given the intermittent nature of the problem.

I did a little more troubleshooting and I think I narrowed it down to the little round twist-lock connector that connects the cable to the tri-sensor. After pulling it out and re-seating it, I started getting a salt reading again. On my cable, it's a little hard to tell if the twist-lock collar is properly locked into position. My theory is that I wasn't putting it on correctly, and the normal vibration from the pump running was causing the cable to work itself just loose enough to break contact on the salt sensor terminals.

Anyhow, I re-attached the cable and made sure that the collar was properly holding the cable in place, and I haven't had the problem for the last 2 days. So I'm hoping that was it.

Anyone else have a similar problem with the tri-sensor cable working itself loose? Just curious if this is a common thing, or if it's just my particular cable.

Thanks again!
Paul

 

[JasonLion]

I haven't heard of the cable coming lose like that before. Most commonly the other end gets pulled out part way when someone trips of the cable next to the control unit. I have hear reports of bent pins, cables with tiny nicks that cut through one wire, a lose connection at the control unit end, cable completely cut through, cables with sharp kinks that broke a conductor, and on and on.

 

[enigmafa]

We have been having this problem with a dozen or so of our units and Autopilot, rather unmotivated might I add, just sent us a case of their new tri-sensors w/ cord pre installed. They must have had a bad run, this seems to be fixing the problems. Is your cord detachable at the tri-sensor?

 

[lpaulriddle]

Unfortunately, it seems that my problem is back. Here's a quick recap:

A couple weeks ago, my (brand new) DIG-220 started intermittently reading low salt. Sometimes it's a low reading (typically 1000-2000ppm) and other times it just reads 0. Actual salt concentration is 3000ppm per test strip. Detaching and re-attaching the tri-sensor cord (tri-sensor end) brings the reading back to normal temporarily, but after a period of time (anywhere from a few minutes to a couple of hours) it starts reading low salt again.

When the problem originally started, I removed the tri-sensor and inspected it. As far as I could tell the unit was completely clean - no scaling on the salt blades or anything like that. So I just put everything back, reattached the cable and made sure everything was secure. The system then worked perfectly for 10 days, and now the problem is back, with a new wrinkle: in addition to low salt readings, I'm also getting intermittent high temperature readings at the same time. The temperature will read 100 degrees or so when the actual water temperature is around 82. Once again, removing the cable at the tri-sensor end and reattaching it clears the problem up, but then it malfunctions again a few minutes or hours later. I've checked the cable while the problem was occurring, and it's still securely connected - so it doesn't seem like it's working itself loose as I had previously suspected.

I poked around on this board a bit and found a pinout diagram for the tri-sensor cable and jack, so for laughs, I checked the resistance across the salt sensor pins while the system was malfunctioning and again while it was working normally. Same results both times: the resistance fluctuates, starting out low and slowly rising to around 1000k ohms over a period of a couple minutes, before going back down and repeating. I get the same results at the tri-sensor pins as I do at the controller end of the cable with the other end attached to the tri-sensor, so this seems to rule out the cable itself as the problem. Of course, I have no idea if these readings are normal or not.

I'd like to try to narrow this down myself before I bring someone in to look at it, because it's hard to reliably reproduce the problem on demand, which means of course that everything will appear to be working perfectly when the tech is there looking at it. Very frustrating...

enigmafa - Yes, my cord is detachable at the tri-sensor.

 

[Poolsean]

First, sorry you're having problems with your Pool Pilot. I would suggest that you take some digital photos or video, especially with an intermittent issue.

Keep in mind too that if you have insufficient flow, the salt blades will not be saturated to give a salt reading (thus 0 ppm), and may also cause the temp to show as higher than actual. However, the flow sensor should catch that and prompt a low flow warning.

Having said that, I would recommend that you contact the service company to make any replacements or repairs needed to avoid the intermittent problems.

The reason for the switch to the permanently attached trisensor cord is mainly due to the number of issues at this connection. Not due to a defective connection, but from weedeaters, foot traffic, pets, water damage, and damage on the pins by improperly connecting the trisensor to the cable.

Hope this helps,

 

[Keats]

15 Jul 09
:grrrr:
I had the same problem last month. My system with a SC-36 cell, was working fine. Then out of the blue, the dreaded RED light. Mine read check flow. When I ran the tests, it showed
0 PPM salt. I know that was wrong. Again, taking it apart and reassembling it made it work briefly.
I tried replacing the flow sensor unit with an older one that I had. Still no luck. I've gone through two manifolds and cells in the past 4 years. I finally decided to bite the bullet and buy another complete manifold. I found one on line in Calif. for $279.00 in June.

I should have ordered it then. I waited a week and tried to place the order and it would no go through. I finally called the company and was told that Auto Pilot told their distributors that they could no longer sell complete manifolds/with a new salt cell.
Funny but now the best I can find for a SC-36 cell without the manifold is about $382.00 - Go Figure Huh!!!

I finally found a replacement manifold without a salt cell for $120.00 plus tax and shipping, and it had a flow switch. I ordered it and when it arrived, I swapped it out and sure enough, the system is up and running. That makes three flow switches so far.

All I can say it that there should be a better design for the flow switch and/or a way to repair them.
Needless to say, I'm not happy. I told my wife that this is it. Next move is Chlorene Tablets and to *$*# with salt systems.

This makes the cost of salt water after my initial Eco Matic system @$1,200.00 from the pool builder in 2001 and the replacement Auto Pilot system @ about $900.00 and the replacement SC-36 cell and manifold @$259.00 two years ago and now the manifold W/O a replacement salt cell for $142.00 a very expensive proposition.

I've got two "Bad" flow switches now to experement with. Nothing to be lost - they don't work anyway. Maybe I can find out what makes them tick? Sure would be nice if someone came up with a rebuilt or a replacement flow switch and or Salt Cell.

Keats, Az.

 

[eastsider]

I have the same problem. No salt,add 875pounds, check flow, check flow to sensor. My Autopilot Total Control SC60 is less than one year old. The end of last season it started once a week or so. This year about three times a week. Most of the time if I cut the power off it will reset but if that doesn't work I disconect the cord at the tri-sensor and when I reconect it resets. I've checked all wires and they seem to be fine.

 

[jsexton101]

Mine worked great last summer and about four weeks this year. Now showing no salt at all and I know it has salt. I already replaced the trisensor and cord year before last and the control board the year before. Any reason why it would just show low salt? This autopilot digital was a replacement for a cubby. I have only had the pool since 05 and had two systems now with replacement of two boards, two cells, and a tri-sensor and chord. Any solution to this no salt reading? I have tried disconnecting and reconnecting the chord and powering down the system completely and repowering to no effect.

 

[Keats]

13 May 11
I just had to repair the power cord again.. I bought a new power cord about two years ago. The first one had a lot of black burning inside the sockets. I cut it open and removed the metal (copper) connector. A replacement cord ran about $50.00 when I bought it about two years ago, and it was working very well.

So now the second cord did the same thing. It had black burning inside the socket as well. I assume that its caused by reversing the electrical flow and possibly some arcing when that happens? Anyway, I went to a large electronics store here in Phoenix to get new crimp on connector to splice into the cord so I could use the cord again. The folks at the electronics store said that they had never seen a connector like that before. It was larger than anything they carried. Using a digital caliper, we measured one of the posts on my old salt cell. It measures 4.6mm or 0.181 inches thick. They had nothing that size.

I stopped at about 5 other places and none of them had anything that size. I finally would up at an electrical store. This is a place that sells parts for electricians etc. The counter man looked at the salt cell and my old connector and suggested a waffle iron
(hot plate) cord with the two prong plug. He got an old dusty cord out of the back room and sure enough, it was an exact fit. I brought it home and spliced it into the Auto Pilot Cord. and plugged it in. It worked like new. So instead of spending another $55.00 plus shipping for an original Auto Pilot cord, I paid $5.00 for the brand new waffle iron cord.

I must mention that I use an SC36 cell (the generic one from Calif. now). The wiring is Black all the way from the control panel to the salt cell. The Red wire is actually spliced into the White wire near the control panel end of the cord. So the Red and White wires are the same... I bought "Bananna" plugs from Fry's electronics store and attached them to the control panel end of the cord because the new cords are sold without the plugs or you can pay more and they will have the plugs attached. I believe the bananna plug assortment ran about $2.00.

My next project is to open the top of my first salt cell that is really shot and see how I could make a better connection over all. I have nothing to loose by cutting into it.

I like the Salt Pool Water but I've had it up to here with all the problems I've encountered along the way. Try to ask a technical question when you call Auto Pilot. It took me about 20 tries to get the lady to finally tell me that the Red and White wires were spliced and covered with a sleeve (to hide the splice) at the control panel end of the wire. They only use the three wire set up on larger salt cells. It was like pulling teeth to get her to finally say that I had it right. Now I've got to figure out how to rig the flow switch. I opened an old one and it's got electrical parts imbedded in a resin of some sort. I'm open to suggestions.
Hope that this helps everyone out there.

 

[lpaulriddle]

For what it's worth, I started this thread a couple years ago and my problem turned out to be a bad tri-sensor cable. The service guy came out and plugged the cable into a "tri-sensor simulator," which is a little thumb-sized gadget that presumably has a few resistors and other parts in it. When you plug the cable into it, it's supposed to produce steady, predictable readings for salt, temperature and flow. Anyhow, he plugged my cable into it and after a few minutes, the readings were all over the map. So the cable was replaced under warranty, and no problems since then (so far).

I haven't had any arcing problems with the cell terminals so far. My cell is an SC-60 with three prongs. I've seen the aftermarket cells on the market, and they're a lot cheaper than the OEM ones. I wonder if there's any appreciable difference in cell life.

Paul

 

[JasonLion]

There have been scattered reports of problems with the off brand replacement cells, but mostly they are too new to be able to tell much about them.

 

[Keats]

FYI.
I've been using the generic salt cell for almost two years so far. It is still running like a champ. That is when the Auto Pilot Cable isn't broken... This one is a clear - see thru - blue cartridge. That's cool cause you can see the water flowing thru it.
I'm getting the required chlorination from it and it was an exact fit replacement.
As for the flow sensor, I know that someone will come up with a generic someday. The sooner the better.
If your thinking about replacing the cell, give the generic cell some serious consideration. No, I do not work for the cell company / store. I'm just a guy with a salt system that's tired of paying thru the nose for anything associated with "Swimming Pools".
It's kind of like saying "Boat" when you need something. The price jumps like crazy cause it's for a boat...
IMHO.

 

[WFC]

Keats posted a similar problem that I have with the DG-220 cell power cable plug. The plug connections are getting hot and then the sealant that holds the female electrical connector inside the plug melts and makes a real mess. A new cable was ordered at a cost of $50. This cell power cord appears to be a weak link in the system.