Author Topic: One for the Chemists - water softening solution.  (Read 3095 times)

Offline awemawson

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Re: One for the Chemists - water softening solution.
« Reply #25 on: January 20, 2018, 07:49:52 AM »
So now the photo issue on the forum is solved I'm uploading a few images of what I've been up to:

Firstly the de-calcifying tank and it's odd sensor electrode set up.

The tank had a broken outlet spigot that I repaired by turning one up from plastic and super gluing it in place. Right sat the bottom of the tank are two electrodes embedded in the plastic of the tank and looking possibly to be carbon, but they are pretty well un-get-at-able  :bang:

The lid of the tank has a long plastic column pointing downwards with a spring on the bottom that shorts the electrodes (Shorted electrodes means 'tank has contents' to the electronics) This spring really confused me, as I could see no way the electrodes could be used for sensing - something MUST be missing. But no, it turns out that the spring is there for initial delivery tests to inhibit the flashing 'low fluid' light - there is a moulded set of German text on the lid that Google Translate tell me is 'remove spring on initial filling'  :bang:

So the previous discussion 'up thread' about conductive liquids may now make more sense to people ?

Well this morning the Postman brought the bottle of RM-110 de-calcifying fluid specified for the earlier version of this steam cleaner - will it's conductivity be sufficient ......... in simple term YES  :ddb:

I temporarily wired the control electronics to 12v to avoid having to run the engine indoors - proved that the warning light flashed when the tank was empty and had no spring shorting the electrodes. Repeated the exercise with the lid and spring which stopped the flashing light, then removed the lid and spring (making the light flash) and poured in a tiny amount of the fluid - just enough to fill the well round the electrodes, and guess what - the flashing light was extinguished and the control valve was activated about every minute or so. All as should be.

Not surprisingly there is electrolysis going on between the sensing electrodes with bubbles (of probably hydrogen and oxygen ???) rising to the surface and indeed this may explain why one electrode is very much shorter than the other. I suppose long term it is feasible to drill out the electrodes and re-glue new ones in, and if I get to that stage their composition should become obvious



Andrew Mawson
East Sussex

Offline awemawson

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Re: One for the Chemists - water softening solution.
« Reply #26 on: January 20, 2018, 08:00:06 AM »
While the MPDS was in the workshop I fixed castors to it's frame so more easily to be able to move it about - oddly in the front lower frame are pre-drilled holes for standard castors, but there was no provision at all  at the rear. Pipe clamps round the chassis frame proved up to the task with slight modification to the hole spacing of the castors.

I had had the pipe clamps in stock for best part of a year, as they were bought to fix  redundant fire hose reels to the framework for feed water and pressure hose. The rolling up of stiff pressure pipe at the end of a cleaning session had always been a chore as it fights back all the way !

So again - whilst in the workshop fix those reels :clap:

It proved relatively easy. The feed water which is only at water main pressure could run though the original reel rotary joint and hence be permanently fixed to the machine. However the  high pressure hose had to have quick disconnect fittings to be done / undone each session, as the high pressure and temperature would easily  spell it's doom :bugeye:
Andrew Mawson
East Sussex