[Solved] Intermittent Activation of Gas Detector in Ferroli Divacondens Furnace and Gas Setup

We have a new furnace since about June this year as well as a new gas installation. Bake ferroli divacondens something like this. It heats water and heats radiators. The stove is located in the kitchen with a window above the stove with a gas and carbon monoxide sensor. The kitchen has a window. This room is 2.20 by 2.00. One day, while taking a bath, the gas detector was activated. We were afraid, we called the gas ambulance and they cut off our gas. They tested the sensors, it was ok, they asked to check the gas hob. The next day we called the hob, the service was also ok. After a month, the gas sensor was turned on again when using hot water in the kitchen. I don't know. What's wrong....for now, silence. But I'm afraid it will be a problem again.

One comma is missing and we don't know if the window is above the stove or the sensors above the window....
Where is the chimney outlet? In the wall next to the window, or vertically led out to the roof. Did the carbon monoxide or gas detector work? What gas do you use? Mains (natural) or propane butane?

Sorry, I was typing fast. The gas and carbon monoxide detector is in the corner above the stove. The window is on the other side of the stove. The chimney outlet from the stove goes to the roof vertically upwards.

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Mains gas used. The gas detector caught fire

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Well, we don't know what type of sensor yet, it looks like Safehaus SGH-01, but I may be wrong.
Did it signal a threat continuously or did it beep for a while and shut down? Occasionally, opening a trash can with fermenting waste can release enough gas to trigger a detector, especially in confined spaces. Does the room have a ventilation stack grille?

Yes, this grate is on the other side of the furnace
And the signal from the sensor was continuous. The water in the kitchen was turned on for a long time and then it turned on

I did not understand what the sensor signaled a gas leak or the appearance of carbon monoxide.
Because if carbon monoxide, I would buy a second sensor, eg Kidde 10LLCO, which has a display and if carbon monoxide is detected, it will show the value on the display. Even in the absence of an indication, you can see the peak value recorded since the last peak reset. This will allow you to better assess whether the current sensor is crazy, or you actually have a problem with carbon monoxide, since the gas company employees have not detected anything.
Your boiler is supposedly a condensing boiler, i.e. with a closed combustion chamber, so in theory the carbon monoxide problem should not occur, but if the current sensor reacts, you need to verify it as soon as possible, because there are no jokes with gas and it cannot be delayed.

It signaled gas not carbon monoxide

the question is what brand is this sensor.
For me, reliable sensors were made by, for example, GAZEX, but if it's some strange Chinese, I'd be careful.
I don't know of any other natural gas sensors you could buy for comparison. Natural gas is odorized, so in theory if the sensor detects a concentration, it should be detectable through the nose, unless you have trouble detecting odors. In addition, if you have a condensing boiler, a closed chamber excludes gas leakage on the boiler side, but I am an amateur, I don't know everything and I can be wrong in this matter. But since the gas company has not detected anything, the certainty of the measurement of this sensor is questionable. Gazex requires periodic calibration, theoretically every year, so it is not a maintenance-free sensor for several years.

And how old is this gas sensor . At my friends' place I saw a sensor with an expiration date and information on where it is recommended to install it

I added a picture

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The sensor and boiler are new. We live here for two months. We did everything new from A to Z

1. What sensor such security and alarms. Buy something decent, not market cheap. Your friend suggested Gazex.
2. I can't see the boiler from the pictures, but if it's an open chamber and an uninsulated chimney, the sensor is quite close and may heat up, and the measurement may be disturbed. Most instructions state about 1m or even 1.5m from the chimney, ventilation inlets/outlets, windows, etc.
3. The sensor can react to other gases appearing in the air (e.g. propane-butane from deodorants or hairsprays, alcohol from perfumes, etc.) so it is worth checking whether, for example, we did not do something and then the detector worked.
4. Semiconductor detectors can react to water vapor (mainly rapid changes), so a lover of an intense, hot bath can trigger an alarm.

BUCKS wrote:

Because if carbon monoxide, I would buy a second sensor, eg Kidde 10LLCO, which has a display and if carbon monoxide is detected, it will show the value on the display.

What does it change? It does not matter how the sensor signals - whether with a diode or a display. If the sensor indicates incorrectly or there is a false alarm, then the LED or display will also turn on, which will show some value, but false. The diode or display is just a form of informing the user triggered by the same system. But psychologically, people catch on that if I have gas on the display, there is gas, and if the diode blinks, the sensor sucks
The display helps with low states (i.e. before the alarm) because it shows that the sensor detects something. For example, we have started the boiler and the concentration is increasing. And this is important feedback that the action can cause something.
If someone wants to play with measurements, hang a few sensors (there will be a comparison), and a sensor with a different type of sensor (it will exclude, for example, some types of false alarms), etc.

In fact, it's about buying a good sensor, reading the manual and taking it to the service from time to time (even if the manual says you don't have to).

Domelski wrote:

What does it change? It does not matter how the sensor signals - whether with a diode or a display.

the display changes what you wrote yourself:

Domelski wrote:

The display helps with low states (i.e. before the alarm) because it shows that the sensor detects something.

an ordinary sensor will only show an alarm, i.e. when the concentration exceeds a predetermined level.
If a value greater than 0 appears on the display in the history of the highest concentrations, it is a signal to increase vigilance, because maybe something is wrong and the problem will appear randomly.
Although this may be a false indication but it gives us more information.
I prefer more data than just information about extreme values or 0 or 1.

everyone. Thank you, we will buy a new sensor.

BUCKS we both know what's up. People just when they see the display and the alarm on it, they will consider it real. And if the alarm is signaled by a diode, then the sensor is definitely broken because you can't feel anything. That's why I wrote it.
They also often catch that if a crappy sensor has a display, it is better because there is only a diode in a decent sensor. Just like the mentioned Gazex, which is also ugly and looks like from the 80s (because probably this housing was designed in the 80s) But still, I would probably prefer a good sensor with a diode, and preferably a good sensor with a display

Purchase a new sensor