Autopilot DIG220 0V .5A from readings

[zoocrew]

I have an autopilot DIG 220 with the SC-48 cell installed. I am getting the dreaded low amps - check cell reading. Salt level is 2800 ppm, but the same reading occurs when the salt is at 3500ppm. I have been fighting this problem for awhile. The numbers that show up are 0V .6A. The system has sometimes given an initial reading of a lower volts in the 23-13v range, and amps in the range of 3 when first starting up, then everything will go to 0v .6a after running for a few minutes. I have replaced the salt cell and the capacitors with no luck. I have tested the cable with a meter to make sure that it is not bad. Does anyone have any other ideas of what to do besides order a new board or system? My plan is to check the fuses this evening.

This system has been a thorn in my side. In the past 6 years, I have replaced every component and cable except for the DIG 220 box itself.

 

[JasonLion]

Welcome to TFP!

What is the water temperature? Have you examined the cell plates visually to see if there is any scaling? What is the percentage setting?

The volts and amps readings are only valid when the cell is energized, which is only a tiny percentage of the time when the water is cold.

 

[zoocrew]

The problem was happening at the end of the summer while the water was still very warm (which caused my pool to turn into a swamp). I ended up draining and cleaning the pool since it was a mess. The cell is literally brand new because I broke the housing on the old one taking it apart to check it. The water temperature reads 75F. I had the percentage bumped up to 75% and then boosted it to 100% to see if I could get any energy to the cell.

 

[JasonLion]

Some of the things that cause low amps errors include: bad connections between the main unit and the cell (either at the connections or inside the cable). The cell power is fairly high amperage, and even fairly low extra resistance on the connections can cause a problem. Wiring the control unit for 110 volts but setting the jumpers for 220 volts. A broken power supply board.

Others that are possible, but appear ruled out in your situation include: calcium scaling of the cell plates, cell nearing the end of it's lifetime, and very cold water.

 

[zoocrew]

We did more investigation on the system today. We put a meter on the end of the cable going to the cell. It read 28V so we know at least there is power coming from the unit to the cell. We did not have a resistor to put on to test for amps. Would a bad tri sensor cause a malfunction of the system?

 

[JamesW]

The tri-sensor is probably not related because the unit is sending power to the cell. A bad tri-sensor would give errors that would prevent the unit from sending power.

You could rig up a test aparatus with some wire and banana plugs from radio shack. That way, you can test voltage and current at the same time (with the right meters). You would need a dc clamp ammeter and a volt meter.

You would need two male banana plugs and two female banana plug adaptors.

 

[JoshU]

Turn the power completely off to the unit. Let it remain off for at least 1 minute. Then power the unit back up. As quickly as possible place the unit in boost mode and run a test within 30 to 60 seconds. Please report back your results.

 

[zoocrew]

OK, here are the results. @ 45sec = 11V .6A, @ 1min30sec = 9V 6A, @2min = 18V 6A, 2min30sec = 20V 6.3A, 4min 28V 6.2A, 4min30sec 28V 6.2A. The whole time the salt level was either 270 or 2800ppm. Boost mode was on at 100% on level 2. The problem light was blinking "bad temp sensor". After 20min the readings were 1.0V .5A. Boost mode on 100% at level 2. No error light for temp sensor, but back to low amps. This is different than what I've been getting on other days. Usually I turn the pump on and immediately look to see the readings as the low amps error comes on. It typically starts at 0V and .6A. Today was different and is a head scratcher.

 

[Poolsean]

Sounds like a damaged power module. All other issues would give you either a high voltage and low amps (normal problem scenario for bad cell, scale cell, bad cell cord, blown cell fuse, low salt, cold water temps), or low volts and low amps (damaged power module or improper voltage to unit). However, 0.5 A with the unit in boost usually indicate a damaged power module, or that the unit is programmed for REMOTE RUNS PUMP. Press your PUMP button and see what it says. If it says REMOTE RUNS PUMP, then you would need to reprogram it through the INSTALLER MENU for SET RELAY (selections are External Timer, One Speed, Two Speed, Remote Runs Pump).

 

[zoocrew]

I'll take a look at that to see if it was reset somehow. Otherwise it seems like a failed power module. I think I'm done with autopilot. I'm sure this question is for another forum, but anyone have any suggestions for a reasonably priced salt system for a pool sized at approx 24K gallons?