PISTON Tank from ENGEL

HI, to ALL.
On The last steps with work on submarine 212A I did several tests on the desktop. Everything seemed to go well except DLX's absence, that even now after a month has not arrived from Germany !.
After assembly I started testing on water(in tub). Waterline is good without requiring for adjustments.
But obviously there is a BUT: I do not know what happens to the ballast tank, does not went to take the water!. Just go 2sec,and it stops for 1sec and so on,even if I hold still, stick in a position to fill!. It sounds as if someone / something is blocking and let him go as he please. And after 2-3 times moving stand still and do nothing.And do nothing even I tray to withdraw,when I try to empty it.Do not hear NO noise, nothing.I opened hull 2-3 times to see if the engine is block from something but it was not so.I do not know what to do.Out of the water and put on the table works!.
I do not think it's the battery on since the table it goes perfectly, the engine that is powered also from there and is working flawless and regulator also.
What do you think .... WHAT COULD BE?.
PLEASE some advice wheel be more then welcome.
MARIUS.

Loose connection, something wrong with the limit switches?

The motor running the piston, are the capacitors on/or connected properly? Might be radio interference?

I have done in several ways:
I tried to move the piston with the engine stopped and with he started ... did not work in any way .... it works perfectly on the table no matter if the engine is running or not ... mechanically is not blocked .... gears moving easily
when the submarine is in the water and is pull out by hand the piston works!!!....and if I put them back it's stops with the same symptoms!!!.
I don't know what else can I tray.
THANK YOU
MARIUS.

Are you sure the limit switches are wired up the correct way round.

It is very odd that this is working on the bench but not in the sub. It is either caused by mechanical distortion (e.g a water connection being squashed or (as Richard says) some electrical fault caused by mechanical distortion or radio reception.

Is this a proportionally controlled tank using a Hall effect sensor? If so is the sensor being distorted or subject to a magnetic field?

Is it pulling a lot of amps? In which case the motor may be stalling (mechanical distortion again) and it is cutting out automatically.

Yes indeed.

I have just been looking through the Engel manual (Thanks Clive!) and it can also have the pressure sensor and/or the low voltage sensor causing it to pump out. You would get alarm LEDs showing though.

Perhaps profesorul, you could give a description of exactly which tank you are using with which additions (Proportional unit, pressure sensor etc ?)

These is my Piston Tank.
https://i.servimg.com/u/f40/16/90/12/89/800_5310.jpg

...and these is the electronics:https://i.servimg.com/u/f40/16/90/12/89/800_5312.jpg

So if I have my reading glasses on , this is a Type EA which is just the basic tank with limit switches only.

So it is fairly simples and all our basic advice applies (Check limit switches, current draw, trapped wires etc.)

Also don't hesitate to send it back to Engel because it will still be under Warranty.