Tips and tricks with the KH director

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Lasse

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A year ago - I buy an used KH director and have run it since that. It has worked fine and during the last months I have use it in adaptive mode. A good help because I took out one of my large Clams a couple of weeks ago - an huge consumer of alkalinity.

However - suddenly it report too long titration time and the graph from the reagent pump shows around 4-5 ml each titration instead of normally around 2 ml. I logg into its page and notice that the pH reading did not move at all when titrating was ongoing. Normally - it normally goes down rather quickly to around 6 and after that slowly down to the break point (around 4.3)

I did not either hear a sound from the internal mixing pump and suspect that it was broken.

I submit a ticket and GHL support team was of the same meaning (after running the KH director from abroad) Either was the pumpmotor/the gearbox/pump or motherboard broken. In order to decide what - I decide to open the KH director and investigate by my self( warranty was not actual) I open it up and try a manual running of the pump (see below)


1684754749742.png


Surprise - it runs and there was a sound when it run. Mount together again - new test and I listen to the sound of silence........again. Bridge over trouble water so to say :) demount - ans still not running. After normal male investigation - look worried, look from different angles and doing a Norwegian reset (just take out the power and back agan) - i was still listen to the same borrowing tune - sounds of silence. Now time for a female way of attack (or at least my wife´s way to kick off her sewing machine) I lift the corner where the pump is situated up (around 1 cm) and let it crash back into the table. Now I hear the sound of rushing water. repeat the solution - silent - repeat again - rushing water and so on. Measured the motor power - it was OK.

Conclusion - probably a gapping contact in the motor - or a stuck in the gear or the pump. In order to see if it was problem with the motor - I hit the engine twice with my hand. And since that moment the internal pump works as intended!!!!!!

I had test a couple of times with the pump not working and add a lot of acids into the system. I decide to use the function "Flush the measuring cell" (red marking). That function fill the measurement cell and empty it again. When it was filled - before it empties - I stop the current action (black) and enable manual override as above - activated the internal pump - flushing the pump and pump tubes too. After a couple of minutes I disable manual overriding and just totally empty the cell (blue)

1684756558555.png


However - the readings was instable and during titration - the pH react in an odd maner. It was going down rapidly and after that going up. The value in the chamber varied too. The variable amount in the chamber was an easy task. It works like this. When you start a measurement - the sample pump fill up the chamber a little. After that the waste pump empty the chamber. If calibration is a little off - it happens that there will be some water left in the chamber before it is filled up again. The readings will not work as intended. In order to empty totally I manipulate the pump calibration a little - took away 2 ml. It was enough in my case - you should see ait bubbles in the tubes to the waste pump as below (befor the main filling)

1684757231505.png

I also change my previous 100 ml into 80 ml sample volume. Its more movement in the cell. Note also the pH electrode with the text facing up


I had to flush the sample cell the way described several times and did a lot of tests. Finally - i get stable readings again.

If you run into problems with erratic readings - it is a good idea to monitor the pH during titration. It should go steady down to around 6.3 - 6.5 and after that slowly down to 4.3. IMO - its also a good idea to run the flush the sample cell function now and than

I have no ide what´s happens with my pump and normally I hate situations with self repairing but I will run the director as it is now and replace/ repair later on.

Sincerely Lasse
 
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Lasse

Lasse

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Update - I hate self repairing faults

After some testing - I could bring it in line again. It works well again (after the initial wrong reading) for a couple of days- Last Friday night I got a very low reading - around 2.3 in KH. This has happen before and that time it was a stuck filter. Not this time. The internal pump works as it should but this time - when it starts - pH decrease in spite of no acid dosing. I fill the chamber - pH around 7.8. Start the pump - pH decrease to around 3. Stop pump - pH increase up again. This without any dosing. Its like the pump is electrical disturbing the pH signal

I have the case in the ticket system - I just publish here to increase the understanding of the KH director.

I´ll be back when I know more

Sincerely Lasse
 
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Lasse

Lasse

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New update

I think I have solved the issue with pH going down when internal pump was running. I pretty sure it was and magnetic/electrical disturbance - I had zip-tied the electrode's cord to the upper side of the KH director and now when I open up again and let the cord hanging free from the backside with no contact with the cover of the KH director - it works without fast down going of the pH when the internal pump start. I will mount the cover again and let it take samples every hour and see if I get stable readings

I´ll be in contact

Sincerely Lasse
 

LOVEROCK

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Any reason why my kh director won’t hold measurements in history , even with record history on , ? Even unplugged it and replug to outlet
 

Gaël

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Lasse

Lasse

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Update

It run for some measurements during night - however instable results. This morning the pump motor stop working again. 2 slap on it awake it. There is for sure some problem with the pump motor. Its need to be repaired.

Sincerely Lasse
 

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