OK, needing help with this one.

About 3 weeks ago my Rituale started playing up in that the machine would start up OK, and come up to pressure, but then after about 10 minutes both of the boiler lights would go out and the boiler go cold. The red "power" light would still be on and the pump would run if I lifted the brew lever.
After speaking to my local dealer, they said that the most likely cuase was the main control unit. It took a while to get hold of one and in the end they sent me a "nearly new" one to try. Well I fitted it today nad guess what, exactly the same problem!!
I stripped the machine again and investigated further, and basically what is happening is that after about 10 minutes the live feed from the control unit to the pressure-stat gets cut, in fact you can hear the relay dropping out. I find it very hard to believe that both units have the same fault so can only conclude that something is causing the relay to drop out. I also fond that if I run water out of the boiler whilst it is cooling after the feed drops that the boiler will not refill.
The only input to the control box other than mains appears to be from the level switch, this goes in to some analogue circuitry (a aomparator), so presumably is some sort of resistive sensor? I can only think that if this goes out of the expected range for "water" or "air" that it causes an error and the feed is dropped. Anyone know about these sensors, or have a schematic for the contol box?

I have also tried unplugging the level sensor when the machine is in its "fault" state and this makes no difference.
I managed to attach a multimeter to the "live" feed to the p-stat and when the fault occurs, you hear a click from the control box and the voltage measured drops from 2440V to 200V, then a couple of seconds later there is a second click and the voltage falls to 0V.

Got me baffled this one!

Here is an electrical diagram for a US model Isomac (not the Rituale) which you can modify to suit your machine and perhaps repost.

Perhaps the reservoir (tank) "weight" switch is wired a little differently for the European models and I would suggest bypassing this switch (jumper it) to eliminate this possibility.

As per the above diagram, a faulty (open) reservoir switch would kill all power to the unit but perhaps the European units are a little different. If you want the drawing in .jpg format, email me at erics@erols.com. Also please edit your voltages so there is no question as to what is going on there, i.e. you say "2440 to 200 to 0". Do you mean 244 to 200 to 0 OR 244 to 20 to 0 ?

Thanks for the schematic post. Unfortunately it looks like the US and European models are very different. For example mine does not have the Solid State Relay. The main difference though is that on your diagram the pressure-stat controls the neutral to the boiler and lamps whereas in mine the neutral is permanently connected to the element and it is the live which is switched by the p-stat. The live feed to the p-stat comes straight out of pin5 of the control box. It is this that is dropping out.
I have eliminated the reservoir switch as this cuts feed to the whole machine, and I still have the main power lamp on, and you can run the pump by lifting the brew lever. It seem that the 2 relays in the control box are dropping out as there is no feed to the p-stat and also the autofill outputs to the solenoid and pump do not function even if I drain lots of water from the boiler, or even if I disconnect the level sensor, which would normally cause constant fill.
The fact that I have to wait quite a time before the machine will function again (the function returns even if power is left on) indicates that either something needs to cool, or that there is some sort of time delay in the control box. The latter is a possibility as there is an op-amp in there with a reasonable sized capacitor which looks to be connected to one of its inputs (haven't had time to properly trace it yet), which may give a timeout function. It would be really handy to have an internal schematic of the Giemme control box so I could work out how it should function.

When I get the time I'll try and do a schematic for my model, not too great with drawing packages though!

It would be really handy to have an internal schematic of the Giemme contol box so I could work out how it should function.

This has been brought up before and, to the best of my knowledge, does not exist outside of the Giemme factory. As you can imagine, this would be considered proprietory information. Is this machine under warranty?

It seems as though one of the coils of the transformer on the Giemme is losing power and since this has occurred on two controllers, the likely culprit is the input side.

Spent more time checking things out again this evening. When the failure occurs there is definitely still power on the inputs to the Giemme box. It looks like power is lost to both relays as the auto also stops functioning.
Out of interest I swapped back to the original controller, this still does the same thing but takes about 1/2 an hour as opposed to the 5 minutes of the "new" one. Interestingly when I quickly swapped from one controller when the machine failed to the other, it immediately worked, which means the time I have to wait normally to get operation again is to do with the controller not something else on the machine.
Tracing some of the circuit, both relays are powered straight from the (rectified) 18V from the transformer, so it is either this dropping, or the low side switch on the other board. I will try tacking seom wires on to the transformer output and see if it is that dropping off as it does seem quite warm when I take the unit apart. I think I will have to try an absolutely brand new one on this.
I have also noticed that my mains voltage is up around 250V and the transformer is rated at 230V, so wonder if it is a bit close to the knuckle.

I was going to say the water low reservoir sensor, but if you can lift the lever and the pump runs, it is not that. Is there a boiler low probe? On the Lusso lever machine there is a boiler low sensor that kills the heating element if the level drops too low.

A thermal breaker would trip but not reset itself, unless it is going bad.

Well, out of curiosity I ran my original controller just on the desk at work with the level sensor input shorted to ground to simulate a full boiler. After about 1/2 an hour lo and behold the boiler feed relay dropped out. Measuring the output from the mains transformer showed no volts at all. Looks like the mystery might be solved!
I left the unit off for about 10 minutes, powered it up again and there was the 18V out of the transformer again.
Looks like there is some sort of resettable cut-off inside the transformer somewhere which is tripping after a while. What are the chances of both units being faulty though, crazy!

What is your mains voltage at work? - you previously expressed concern.

What are the production codes, if any, from these two units?

Why not give Giemme a call? I would think you would get their attention if these units happen to be very close in mfg time especially since you are experiencing similar problems with both.

In reality, thinking about it the whole of Europe (well EEC anyway) is now "officially" 230V, but the tolerance is wide enough to allow the UK to stick to the existing system which means we are around 240V, and the close to 250V I see at home is within tolerance so shouldn't be an issue. Most of the transformers you buy here are rated 230V.
What I have now discovered is that when the failure occurs, the secondary windings measure open circuit, so definitely something is breaking the circuit (primary remains OK), and after 10 minutes or so you can measure 75R, so looke like a resettable fuse of some sort.
It will be worth checking the numbers to see if they are a similar date as you say. Howvwer mine worked fine for 3 years, so cannot have been much wrong in originally.
I have found a suitable transformer from RS, and as it was £2.50 have ordered one, so we'll see if that cures my problems.

Another update.

Harrumph, the transformer did not arrive today which was annoying, I want to get the machine back together as we have a first time buyer coming to view the house on Friday, so need not to have the machine in bits all over the dining table!

Anyway in frustration and to prove a point I used a bench power supply to feed in 18V DC to the control unit on the DC side of the rectifier, and popped it loosely back in the machine. Lo and behold an hour later the machine was still running perfectly thus proving the transformer to be the issue. Strange but true. Fingers crossed the transformer will come tomorrow.