Did a complete service for an acquaintance, including replacing elements and total teardown. Machine was totally dead when I got it and had indications of scale everywhere. The 15A fuse was blown and the pump frozen. The owner indicated he did not descale regularly or change the softener resin. Every fitting I removed was clogged with scale, so full teardown seemed in order. All O-rings and seals were replaced.

As related in other threads, the elements heated, but tripped a GFI. The pump had been leaking for awhile and took out the front bearing on the motor. While waiting for those to get sorted I proceeded to take the brewing assemblies down to individual bits, but left the chassis and electronics alone other than the fuse. The elements came in and the motor and pump now work as should. Got the machine back together and started initial testing today. Filled the boilers as per the service manual. Pump and flow meter worked fine and shut off, presumably when the boilers were full.

When the machine is first powered up it heats and both the fill and heat indicators are steady as well as the green on/eco lamp. All the other LEDs flash on and off at about 2 second intervals until machine is shut down. The owner said that the fill and heat lamps should turn off when the boilers are full and up to temp. And once the machine is in ready state, the only lamps lit should be the on and whatever brew button is selected. If left on, water starts to drip from the drain fitting and increases to a steady sputtering with steam much like when a vacuum breaker starts to close, only it just increases until the machine is shut off. Seems to be seriously overheating. At no time do any of the brewing or steam and water buttons work.

The manual is pretty useless for troubleshooting and repair. Closest thing I could find, and not an exact match, indicated the temp probes or elements. The elements are new, so tomorrow I'll pull the thermocouples and test with an ohmmeter.

Thanks in advance for any ideas you can think of, this is the first auto machine I've attempted and looks like I found a doozy. One positive, no leaks.

I think your opinion that the machine is overheating is on the money.

Initial thoughts are the temp probes (or one of them - probably the brew boiler) are bad or open circuit.

You will already know that only one boiler heats at at a time on this machine.

From cold startup, the brew boiler heats first - at least from observing mine that seems to be the case - then the steam boiler kicks in.

The lights flash on all the brew/steam/hot water buttons until the relevant boilers are up to heat. When the brew boiler is up to heat the three brew button lights go out - subsequently the steam and hot water button lights go out when that boiler is up to temp.

Buttons do not operate while the lights are blinking, but you can check they function correctly by switching on temporarily in boiler fill mode, which disables the heating, but allows all the buttons to operate. This would at least check out the logic board to some extent.

I think that there is both a time-out and over-temperature logic built into the machine if the relevant boiler has overheated, or not reached programmed temperature within 10 minutes. I confess to being a bit confused by the error indicators listed in pages 3 & 4 of the "procedures" section of the book, and at the end of the book in the problem solving section, but you might have a look and see what you make of them !

If the machine thinks the brew boiler hasn't got to a high enough temperature it may be that the steam boiler doesn't trigger at all. I would not expect the drain fitting to leak though - that sounds as if the threads are not sealed or it is not seated properly. I'd have expected the over-pressure valve in the brew circuit to vent instead.

Have you observed the pressure in the brew boiler circuit from initial switch-on ? From cold, the pressure rises very high to start with, as the brew boiler is full of water, and although water expands only very small amount, it's enough to raise the pressure to the point where the expansion valve vents a tiny amount. Hardly noticeable in the expansion valve pipe though.

When the steam boiler kicks in you will know it has happened; the heater light goes out briefly, you will hear a relay click to switch the heating route to the steam boiler, then soon afterwards you will hear a click as the steam valve opens and closes quickly to vent any vacuum, as this machine does not have a conventional vacuum breaker.

The exact logic in the control box is a bit of a mystery - to me at least - but it's clear that there is some "PID" login in the circuit that regulates the heat input in relation to the measured temperatures in the boilers and the rate of change. You can hear this in the steam boiler heating which starts off full on, but reduces once heating has got to a certain stage.

When the machine is ready to brew, all green lights on the buttons will be off: the "on" light will be illuminated: the heater light may be in either state: normally the water level light will be on, but steam and to some extent hot water can still be drawn while the machine is refilling.

One other thing that had me scratching my head a while ago, was the boiler water level flashing when it was clearly full. Gallic logic (!) uses this also as an alarm to tell you the pre-programmed volume of water has gone though the machine, and it's time to change the filter. This volume is programmable or you can turn it off completely.

Wow, thanks for the detailed reply, more useful info there than the manual.

Tried the button test, and it dispensed water with all. Pulled the thermocouples . One tested 234k and the other 222k, at 25.6c, which seems to be within tolerance. Also tested the fill sensor and it was good. While I had the temp probes out I confirmed both boilers were full.

Did not know the boiler filling scheme, which led me to think that the control board is not sensing/triggering the circuit when brew temp is reached for element shut off. Let it run for awhile and checked the brew boiler temp at the main plate of the 'boiler set' (no part no. or name in manual). When the tempt reached 210f on the brew end, shut it down and checked the temp at the steam boiler end. It read 145f, which I think is mostly mass heat transfer. This would suggest the control board is not being triggered for brew set temp and kicking on the steam element. 210f seems way too high and doubt the owner has it set that high. Will confirm. Did not fool with the wiring except for what was needed to get the boiler assembly out, only the two thermocouple leads and front panel connector were unplugged from the control box, but will go over all of it with a fine toothed comb anyway.

The collection block for the drain isn't leaking. The Super Pressure Valve at the flow meter is leaking and the output is flowing out the drain fitting. According to the manual it is a pressure safety relief valve for the pump and not adjustable. I had disassembled it for descaling and put it back together as original. The rubber seal was indented, but reversed it. Will fiddle with it a bit more.

LED situation remains the same. Heater, Fill, and ON remain lit while the remainder blink on and off at about 2 second intervals.

Thanks again for the help.

PS - I think this is an early machine, no gauges.

aah - ignore the pm I just sent you asking about that.

OK - it seems that the fundamental problem is the machine not switching the heating from the brew boiler to the steam boiler for some reason, and everything else is following on from that. The steam boiler definitely isn't heating based on your temperature readings.

Both the brew boiler and steam boiler target temperatures are set using the front panel - page 2 of the "procedures" section of the manual shows you how to to that and to check it - it helps if you can think in binary I think 210 is about 99 C - the highest setting allowed is 98 C on the early versions of the machine.

The over-pressure valve protects the whole brew hydraulic circuit (actually the pump has its own pressure relief valve). The over-pressure valve is specified to start to release at about 12 bar and isn't adjustable as you know.

Did you check the thermistors at the plug that goes into the board - or are they the type that has an intermediate connection in the wiring ? I'd make sure they were tested at the board end and the connections are good and clean. Apologies if that is patronising....

Thermistor values seem OK for this version.

Definitely sounds like either the thermistor or the "brain box" is at fault, either not sending the right signal to switch off the brew boiler heater, or the box not responding to it, or the relay switching between brew boiler heat and steam heat isn't responding.

Do you know if the machine was fully operational then failed, and how it failed ?

Dunno, but it might give some clue.

PS - again sorry if patronising, but you're sure you have the thermistors connected to the correct plugs on the board - and not the wrong way round ?

Might be worthwhile to check them when they're hot to see if the values have dropped, or even swap them over as an experiment.

Thanks again Rob, will check the connections again. Both thermistors seemed to be identical, but will look at the teardown photos to double check the connections. I did notice one of the leads coming from the board had a white marker, but no corresponding mark on the lead coming from the thermistor. Both thermistors test at the same resistance, but will retest with boiling water.

As both temps are programmable, it seems they would not use thermistors that trigger at a specific different temps. The manual only gives a single test rating and procedure, and indicates the same part number for both.

If both thermistors are identical, it should not matter which leads they are plugged into on the board.

Is it possible the thermistors were put back in the wrong boilers? It would explain the problem and be a simple fix.

Ira

Yes it does matter - quite a lot actually

Yes - the thermistors themselves are identical. However,they aren't intelligent devices and they don't trigger anything themselves. They just drop their resistance value as they heat up.

The way it works is that the software reads what resistance they currently have, and then responds by switching the heaters on and off as appropriate.

If you plug the wire from the thermistor screwed into the steam boiler into the socket for the brew boiler, as the steam boiler does not heat up first, that thermistor will not get hot and the software reading its resistance value will just tell the brew boiler heater to just keep right on going and never stop....

(Eventually after about 10 minutes it should time out as a safety measure, but by then everything has gone completely haywire.)

Just to be sure, the coffee boiler thermistor is connected to CN1 on the board (the left one as you look at it from the front of the box) and the steam boiler to CN2.

If they are the other way round, that is the problem