Replace Melitta CI heater

After it took me a long time to find out about the system errors 5 and 6 of my Melitta CI, I wanted to share my findings with you .

I'd like to point out that I'm a layman and therefore can't give an explanation and far-reaching explanations.

System error 5 - Machine does not heat. Usually means a defective instantaneous water heater. After I had exchanged the instantaneous water heater I had to find out that not the block itself, but the temperature fuse(s) had burned out. (Simply check the passage with the multimeter). These are located in the plastic sheathing of the blue and brown cables under the screws on the thermoblock. I have found these on the one hand under this link: ( http://www.coffeemakers.de/Melitta-UEberte...120/220-BL-3013 ) (hope I can post it here) and on the other hand you can find it at Conrad.
Another reason may be the NTC sensor. Simply unscrew this (8er key) and replace it. (Also to be found on the above mentioned page. )

With which we are already at system error 6
Systemfehler 6 ist nach my Erkenntiss: Short-circuit error
The NTC had more or less resolved for some reason unknown to me and the wires came directly together and caused a short-circuit. After the exchange of the same the mistake was gone.


>I hope this helps one or the other.

If someone could tell me what kind of resistance there is in the NTC component I would be grateful.
Is the blue or brown cable coming to the Heater-L slot? I thought I did it right but in the heat of battle I'm not sure anymore..


Greetings
Alex

Heater-L will mean <Line>, so <Phase>, and there would be the brown wire.

HWS

Hello. Got a similar problem (on a Melitta CI), maybe who can help.

It started with system error 5 and the thermal fuses on the heating block were defective.

Now here's what I've done:

Instead of a thermoblock a bulb is connected and instead of the NTC in the thermoblock a potentiometer. By this simulation I could recognize that the original problem, that the thermoblock overheats, is unfortunately still there. Light bulb (simulation Last Thermoblock) lights up constantly, although temperature (simulation Poti) has been reached for a long time and coffee is prepared (of course cold, because of the simulation). Actually, the light bulb should go out after reaching the temperature, or at least after making coffee when the machine is in standby. The light bulb shines all the time.

Suspicion of the triac that supplies the thermoblock.

I desoldered the Triac BTB12-600BW and tested it with a small circuit on a DC voltage. The triac switches as soon as I apply voltage to the gate, I disconnect the voltage from the gate, then the triac switches off again, normally, the triac should remain switched through after all (at least with DC voltage, with AC voltage the behaviour would be correct).

The big question now is: Is the triac defective or is it a problem on the circuit board?

I ordered a triac once, but if it's not that....

Has anyone had the problem and can answer the question?

Hello, Geri,

what was the cause of overheating? Same problem.

VG Keenen

Resistor R74 is causing a short circuit to the copper track below.
Lift up R74, that its bottom side does not touch the board below.
R74 is located close to the heater triac.