My APEX just dumped 200ml of alkalinity instead of 2ml

[CMO]

@RussM is there maybe a way to program a virtual switch to shut down the doser if it exceeds a certain amount in a given 24 hour period? It scares me that my entire tank could be taken down by accidentally pushing a digital slider to far to the on instead of auto position...

Or any other idea to provide a fail safe to a situation like this?

 

[luckyazn6]

Cant you set to turn off doser when ph gets to a certain number

 

[Stickboy15]

Ive had this happen before I turned my dos off my accident and put it on the ON setting and not AUTO and it dumped a bunch of all in the tank lucky I was in the room and saw it happen and stopped it asap

 

[CMO]

Cant you set to turn off doser when ph gets to a certain number

Possibly, but 2 concerns come to mind.

1) Will the change in the PH reading be quick enough to stop the overdose before it doses too much? I imagine by the time the PH threshold is triggered you will have already dosed far too much since it takes time for things to circulate through the system and register. A lot can be dosed in relatively little time as seen here.
2) Given normal PH swings the cut off value would be different for a constant buffer. My PH ranges from 7.9 to 8.20 for example; so if I set a PH trigger at say 8.5, that's a big difference in cushion depending on when the incident happens in the PH cycle.

Seems far simpler to just shut down the doser with some code if > x mls are dosed in the trailing 24 hours.

 

[snoopie]

I have notice the switches lag before in doing this. I have got myself into a habit of fully turning it on or off which ever mode I want it to be on. Wait until it does then switch it back to auto. It is a pain that we have to do this but it helps.

 

[Joe Batt]

Man this is terrifying. There really needs to be a fail safe built in that stops the unit if the maximum scheduled dose is reached (or something similar). I heave nightmares of this happening.

Sorry to hear it.

I agree, along the lines of the ATK where by you couldn't set it to allow this amount of dosage unless you specifically authorised it. ie if the last say 5 doses were X ml the next is automatically limited to X plus a nominal value or it gives an alert that you have to accept before proceeding.

The selection buttons on the user interface should also not be so close together that it allows for inadvertent selection of a critical control. That is poor design. I work in the aviation industry and that would never be allowed.

 

[Joe Batt]

Cant you set to turn off doser when ph gets to a certain number

I have this already implemented on my system for the dosing.

If dKh > 8.05 Then OFF
If pH > 8.4 Then OFF

The only problem is that this happened because the system was inadvertently switched to 'ON' and didn't respond to the 'Auto' command when it was given. When the system is in 'On' any coding you have for the dosing is ignored, any safety system you have programmed in is ignored 'On' is 'On' until the dosing tank runs dry or you switch it away from 'On'. There should be some failsafe in this for sure.

 

[Tft12]

Really sorry this happened to you but thank you for sharing.

 

[CMO]

And additionally, with as many times as dosing amounts need updated across several intervals and solutions, its just begging me to forget a decimal and enter 95 instead of 9.5. Updating the DOS needs to be a sober event for sure . I always select all DOS outputs to visually compare. One more annoyance with this though is that the scale for the current and other selections is different even though they're set to the same amount - 9ml in this case.