Solar Project Pump - Internals

[Kev888]

I had a 14w solar project pump fail on me recently; something in the electronics has gone. So I thought I'd destruct it to have a look at how it was constructed:


It looks pretty honest, the bearings seem to be self-aligning brass or bronze bushes on a tiny plastic shaft. It definately contains electronics, potted into the white disc/cylinder which I severed from the circuit board, which was stuck onto the back of the metal coil-housing.

I was a bit surprised to find a few small particles of grain around the magnet/shaft though. That also looks stained with wort and there are some score marks around it, though without opening a new pump I can't be certain if its the normal condition or has been caused by use in brewing (I'd been circulating steriliser/cleaner for over a day before it packed up).

Anyway as I was interested to see the innards I though others may be too.

Cheers
kev

[barneey]

Great piccy Kev useful to know whats inside,

Have you tried putting it back together yet? ie would it be possible to clean etc

[Kev888]

It would be possible to unscrew the front cap (the bit with with threaded pipe connections) and put it back again, but after that things get more tricky - its definately not designed for regular disassembly.

The little silver clip is one of those one-way/one-shot things that is pushed over the end of the shaft and into a groove - I partially destroyed it getting it off. Then the rotor and metal plate/washer came off easily enough, but the bearing housing is a tight push-fit and needed digging out - it was largely intact but a bit war-weary afterwards so I wouldn't expect it to survive regular removal. Once out though, the magnet could easily be withdrawn. Possibly with better tools or great care you could do it occasionally, but it would be a risk if it weren't already broken.

(The rest wouldn't need to be removed for cleaning, and most of it is glued together. I also had to break the electronics to split off the potting compound).

Cheers
Kev

[Wolfy]

Here is my Ebay purchased little brown solar pump (that I pulled apart - just the bits that will be in contact with the liquid):

I know many people here like and use them, however there are a number of small internal metal (and other material) parts, which gave me concern about how sanitary they will stay.
Since I had two, I put it back together without the little fiddly circlips (bottom front of the picture) and now a few brews later my other pump broke but this one is still working.

Unfortunately I have had issues with mine when I turn them off after a period of use (like recirculating wort via the HERMS) they don't always like to turn back on, and one has broken - never to work again - after using it only a few times.

This is my remaining working little brown solar pump, that I pulled apart mid-brew day - due to it not wanting to re-start.
As you can see there is quite a lot of grunge and gunk around/in the shaft/housing - even when I cleaned them after each use - by running cleaning solution through the pump for 15 mins.

After the pump was cleaned and reassembled, it worked again and I completed the brew day (but I don't know if the cleaning it or letting it cool down was the reason for it workng again)

[Kev888]

Hmm, thats interesting. Mine failed on hot days when pumping hot or boiling liquid (one permanently, the other intermittently working). In my case it definately seemed to be electrical/electronic rather than mechanical, and as I'm running them off a (very) regulated DC voltage well within spec, I'm currently suspecting the electronic's lives were perhaps shortened by the heat. Possibly made worse by going for the higher powered version - more power/heat in the same small potted package.

I too also discovered organic stuff around the shaft even after a day or so of pumping hot PBW cleaner through it - so I'd be concerned about just a quick blast of sanitiser or hot wort before use; you'd want to be sure it had properly penetrated.

Unfortunate really; they're otherwise great little pumps at an amazing price; it must be said that they've served me well until now.

Cheers
kev

[bumblebee]

Just reading this thread, now I have never used this pump but have in the past used a similar (although much bigger) style pump for running a series of fish tanks, those pumps had a magnetic shaft etc and were running 24/7 but on occasions if turned off would not turn back on.The answer to the problem on almost every occasion was to clean the magnetic shaft and it's housing of any debris .... I'm not saying that's the cure for these pumps but something worth considering

[Kev888]

Yes I can see thats a possibly - perhaps could fit with Wolfy's case, I'm not sure. I found with mine that the intermittent one needed cooling (or at least resting) to recover for a time, and the permananetly broken one seemed to have only some of the magnetic coils/fields operating, so it could cause the magnetic shaft to twitch sometimes but wouldn't continuously push it around.

Cheers
kev

[barneey]

I`ve yet to break a solar pump, that aside I`m more concerned about the gunk inside the thing. I only use them for hot liquids (the last being from the boiler to the plate chiller). I would definately think again for any cold wort / beer applications tho.