Very odd thing happened with the last batch

[Tony]

Don't know why - pump started to sound funny and lost all pressure.

I decided to take a sample and cracked open the bottom drain port and nothing came out!  Rather odd given it was pumping 90C bio around.

Suddenly it let go and dropped a bunch of black hard lumps.

But, the odd thing is that the oil was pre-filtered, settled and definitely free of any crap when pumped into the processor, and I'd dried it the night before.

I'm not sure where this lumpy black stuff came from - it looks like the kind of thing that might accumulate on an immersion element but not obviously burnt and smelly like that stuff is.

So no doubt the pump is blocked with this stuff, and will need dismantling to clean it out.

Very very odd.

[Rotary-Motion]

hmm deffo sounds an accumaltion due to something... maybe some orrifice corner of the system isnt havin the same flowrate/pass like a pipe tube would shoot it through/passed, and once a bit of it starts to form it acts like a magnet and grabs more?

seen this or simarlar on 100% veg running inside fuel tanks moreover meatal fuel tanks or part metal sender units of the galvanised type variety, its a grabber of fats and then builds up / grows on said metal...

maybe change pump for a better internal flow / pass one, i guess pumps can have internal pockets or nooks and crannies or gashes where the ol bio can congregate...

[Tony]

Not sure it'll be trapped bio/glyc otherwise everyone that had an inline heater would experience it every batch (as they always have a pool of liquid in, even after the system is drained).  If I was going to bet on anything, it would be burnt on crud from the heating element.  When I did a Chinese oil batch it burnt out the element because so much crud accumulated on it, it insulated the element from the oil and it overheated!