Viessmann Vitodens 111 - NTC sensor - the boiler does not heat domestic water in

Boiler: Viessmann Vitodens 111
Age: now 3 years old, identical fault was under warranty after one year of use
Description of the problem:
The boiler did not heat up domestic hot water irregularly, most often in the morning, hot water was only sufficient for one shower. The boiler turned on the blower (noise was heard) and displayed the tap icon, but it did not turn on the burner (it also did not display the burner icon), there was no audible attempt to ignite the burner and the electrode crackling, and it did not display an error message.
Reset, restart or service mode and manual burner control (left knob to the stop) helped. The situation repeated itself every few days.
After a week of replacing various parts, including the motherboard, the service finally replaced the NTC temperature sensor - it helped.
After a year and a half (after the warranty), the problem repeated.
I measured the resistance of the sensor (at room temperature of about 25 degrees it should have a resistance of about 10 k? (mine was 0.8). After taking it out, it turned out that the tip was worn and the sensor was covered with a green crystalline bloom. This indicates electrochemical corrosion and precipitation of copper salts. was replaced under warranty by an authorized Viessmann service, so either there is a problem with the design of the stove or cheap Chinese replacements are used.
I put a sensor from an old 10-year-old stove (I ran it previously with a simple ohmmeter). So far it works fine. Photos of the NTC sensor are attached.
Note before removing the sensor - turn off the water (of course, disconnect the electricity first).
Maybe someone will find it useful to describe this unusual problem.
Regards DSos

Hello.

And what did you block the hole after the damaged sensor, unless the se sensor of the old boiler matched in place of this.
If the sensor from the old boiler is mounted somewhere next to it, for example: clip-on, and the damaged sensor is only sitting as a plug, it will start to leak in some time (water will start to flow out on the side of the electrical connections).

Best regards.

I recovered the sensor from the old Vitopenda, fortunately there were some old man's parts left in the attic - I hope it is made of better material and will last longer than the one installed by an authorized service center.

In my opinion, this is not a problem with the design of the sensor but the installation. I wonder what the rest looks like.

do you know the cost of such a sensor?

Thanks to Dsos for describing the problem, it has an identical situation. Suddenly no hot water at night. The technicians have deadlines in 5-7 days. A prosaic repair. The cost of the sensor is about PLN 200.

I have the same problem. The sensor at the heat exchanger for domestic hot water has corroded so much that everything underneath it. By the way, I found on the internet one with the symbol 7819967, but the diagrams show it as the one at the main heat exchanger (for what). Does anyone know if it is the same?

It seems to me that I installed such a sensor at the hot water exchangers. I did it some time ago, so I don't remember the code, but it looks identical. The only difference is that my sensor was made of stainless steel (silver), the previous ones were made of bronze (gold) and unfortunately they were damaged. My original one was golden.

kz61 wrote:

In my opinion, this is not a problem with the design of the sensor but the installation. I wonder what the rest looks like.

I have the same problem as I wrote in this thread. I have a new, correctly installed installation with water after 2 filters and a softener (water not too soft but optimal), among others. with a hydraulic clutch to ease the stove pump as if the electronics have closed all circuits. I also have a clean, after 2 checks (after the first only smaller fragments of the floor pipes after installation), the filter on the circuit, Nothing except this sensor has never failed and it looks perfect (only inspections need to be done regularly, otherwise the hot water stepper motor is cut).

reeboot wrote:

It seems to me that I installed such a sensor at the hot water exchangers. I did it some time ago, so I don't remember the code, but it looks identical. The only difference is that my sensor was made of stainless steel (silver), the previous ones were made of bronze (gold) and unfortunately they were damaged. My original one was golden.

This is also the case, they are the same sensors. My new one is also made of stainless steel. It looks like the soft water installation (not too much) dissolved that sensor, which means it was made of extremely weak materials. And it was damaged to such an extent that I broke it by taking it out because at the end it completely dissolved it. I had to squeeze it from the inside of the structure and I got tired (the stove had to be dismantled a bit, and this and that became unsealed - eh ...). Viessmann also gave bodies on this subject.

Hello!
I have a card with NTC 33 and it's damaged. I want to replace it but I can't because in my country I can't find it.
How can I replace it with an equivalent?