ECM Giotto Premium water level cutoff
So my long term faithful Giotto Premium has stopped working.
Power on results in a green front light and one small 'click' sound internally but nothing further.
I'm guessing that this might be a water level sensor problem and I'd like to at least discount that before sending it out for service.
How can I best override the water sensor?
It's basically a white wire from the control box attached to a short probe into the side of the water tank connector.
A green wire attached to the underside of the machine with a metal probe up from that and into the water tank through a sprung valve.
Is there is simple way to bypass the sensor so I can determine if this is the core problem?
Is it as simple as disconnecting the green earth wire temporarily?
I'm not particularly electrically minded so I haven't really quite got my head around how this mechanism works but I'm guessing it's pretty simple.
It will almost certainly be the control board. The transformer can go on them.
Hmmm... well if it is the transformer then that would be my 3rd. Clearly a weakness in these machines so probably time to sell it off and look for something new!
I would however, still like to understand how the water sensor works and how to override it just in case that does prove to be the issue.
Last edited by mj; 2nd March 2019 at 04:41 PM.
MJ I take it you are aware that there was a retro fitted / upgraded / modded from the Manufacturer
Control Board / Wiring loom.
Has your machine received this?
Search back posts. TC advised many owners of this back when.
IIRC a sub fault was the OEM circuitry kept blowing the board.
Yes... that got done as part of my 2nd control board replacement...
Was pretty unimpressed that I had to go through 2 replacements before that was sorted but wasn't the fault of the repair guys for either repair.
I'm sure I wasn't Robinson Crusoe... but it's a pity that what has been a solid machine otherwise had such a basic flaw that the manufacturer should have been across quicker.
To be fair I think I bought this machine in 2005 so it's not done badly.
If this fault is nothing more than replacing the water level probe I'm happy to sort that myself but I'm trying to work out how I confirm that rather than randomly changing things.
I'll not be surprised if it comes down to needing a new controller and for that I'll get someone to do it and replace a few seals and clean out the boiler etc along the way.
At this point I'd just like to know if there is a quick way to verify that it's NOT the water level sensor by bypassing it somehow.
The low water cut-off just senses whether there is water in the tub. As you mentioned there is a green earth wire to the tub central metal rod, and a white wire , mounted half way up the tub externally, if there is water in the tub, it senses the circuit is complete (because water is conductive) and allows the machine to run. If there is no water , it will cut power to the machine . If it has tripped, it will usually cut power to the pump also, so that is one way to rule out the low water cut-off (if your pump still runs, it hasn't tripped ) Some versions of the Giotto (there are lots) have a spare earth wire floating around inside, so you can connect the white wire to that if you're working on the machine , this will also by-pass the low water cut-off
If you're hearing the faint click of the board relay, it could be other causes for it not heating - pressurestat faulty , heating element open circuit . If you're not handy with a multi-meter and electricity, time to take it to a service agent
I may be away off, but I once had a problem with the low water sensor on my Rocket giotto. It kept on tripping because it wasn't getting any conductance from my filtered water - which is how the sensor works. I ended up having to fill the reservoir with tap water for a single fill. You can also add a pinch of salt to the filtered water.
At this stage nothing runs other than the green 'on' light and the initiating click of what I would also assume is the board relay... this might mean that the brainbox is ok and it's one of the other elements.
I don't believe that it is a water quality issue although it could be a problem with either of the water sensor probes not working due to old age and corrosion etc.
I'm just trying to understand how the water level circuit works so I discount that before sending it off... I'm not particularly handy with multi-meters nor wish to trial and error a repair too much.
With the water tank out, there is water still in the plastic well that houses both probes, and fits the seal of the tank. Assuming that there is water in that well housing, in theory it should still conduct between the two probes which would show that this is not a particularly fail safe way to do a water level check (although it has worked fine for many years).
Also if that is all true, one way of discounting the water level sensor as the problem would be to directly connect the green and white wires which should be fairly simple to do as there is enough length in the green earth wire to run it to the white... or possibly just alligator clip another wire to each contact point.