[Solved] Smell of gas sensed under the Junkers ZW14-2DV KE combi boiler

I have a stove as in the subject. For several days the house in which it is installed has not been inhabited. So I turn on the stove almost every day for about 2 hours.

I noticed that as I enter the next day into the room where the pioec is mounted gently and only under the stove you can feel the gas!
This only happens when I leave it turned off with a round transparent on / off button on its housing or with the plug removed from the socket, but the gas valve open.

I suspect:
- a leaking gas valve head, but only in the "open flow" position ... only that then between the gas consumption / heating cycles it should also escape
- traces coming from the furnace itself, for the conditions described above

After starting the furnace I am in close proximity to it and I don't feel gas at all. Similarly, during ordinary daily work, when the house is inhabited.

Do you have any idea?

Inspections carried out regularly by an authorized Junkers service every about 1-1.5 years. Checked and reliable technician.

cynamonik wrote:

Checked and reliable technician.

I think I would call him. But first I would turn off the gas and turn off the stove and not wonder when something was eating .....

Write down the meter reading and compare over time. No jokes with gas. I have already seen many boilers burned due to gas leaks at the connection.

Thank you! I will turn to Majster - there is nothing to worry about. I turned off the stove and turned off the gas on the valve "in front of the building"!

As nobody lives, often the smell of "gas" can come from dried siphons (shower tray, bathtub, drains ... etc.). Of course, it does not negate the leaks of the gas installation.

I am making up ... the called gas filler checked with a gas sensor that the leak is under the screw connection of the assembly marked on the drawings:


After replacing the seal, it is approx.

In addition, the "union" removed, which was installed BEFORE the shut-off valve ... can be seen clearly in the pictures. We have such professionals !!!

Which is VERY IMPORTANT ... with the gas sensor in my hands, I checked the installation. It turned out that there are still 3 leaks in two buildings !!! Surprisingly, there was no smell of gas at all, which, after all, is very strongly odorized - even putting your nose under unlucky places.

Check the installations as you get the opportunity !!

There should be absolutely no screw connections or long threads upstream of the shut-off valve, as these are potentially leaking places (especially so-called long threads). This screw connection marked with an arrow (behind the valve, so in the right place) had to be damaged (crack on the cone, etc.), unscrewed or the pipe positioned incorrectly. By the way, there are also fittings with O-rings that ensure 100% tightness (until the O-rings grow old).

-west wrote:

As nobody lives, often the smell of "gas" can come from dried siphons (shower tray, bathtub, drains ... etc.). Of course, it does not negate the leaks of the gas installation.

Buddy from siphons smell is completely different. There is a THT odorant in the gas, and in the siphons trash from putrefaction (by the way, so-called biogas, but this is already at a larger scale).
They once stopped all production at a large factory because they felt "gas". It turned out that there was no siphon in the sewage grate in the boiler room and the boiler "extracted" air (stench) from the sewer as conditions were favorable.
Gentlemen, you should check the smell of gas at the stove, and how in the siphon, e.g. sinks or sinks (smells more like garbage).
I remind you that the gas itself, or rather its methane component, has no smell. That is why it is odorized.

We close the topic - the solution given slightly above - in post # 6. thank you for help and suggestions!