Immergas Victrix 26.2.I Boiler: Error 10, Pressure 1.3, Circulation Pump & Safety Valve Issues

I have a problem with circulation pressure. For a long time after the night, when the stove was turned off (night temperature lowered), the pressure in the circuit dropped below 1 bar and it did not start. After refilling, it worked normally until night... There were no leaks in the circuit. The service technician found damage to the expansion vessel, yesterday he replaced it with a new original one, this morning error E10 again and in the circuit 0.
What can be? The new vessel is damaged or the diagnosis is incorrect?
Maybe after replacing it, the system needs to be replenished for some time?

Moderated By ArturAVS:

In the future, please start your own topic and do not link to someone else`s where the discussion has ended long ago. Thank you.

I suggest checking and setting the air pressure in the diaphragm, then bleeding the system well and letting it air for a few days, and if it continues to drop, there is a leak in the installation.
Question - is the outflow from the safety valve controlled or does it flow into the sewer?

In total, it lasts 2 weeks after the replacement. I think there were only 2 days when it didn`t have to be refilled in the morning. The pressure in the diaphragm is . Refilling approx. 0.5 l according to the water meter. The safety valve is in the boiler casing and there is no outlet to the outside, but it is dry underneath, the automatic air vent also has no stains/leaks, like new. The heating system for the domestic hot water tank is cut off because I do not use it: the domestic hot water is heated in a separate electric boiler (PV). and there are no traces on the circulation system, some of the pipes (PVC) run in the walls, of course, but there are no stains or dripping from the pipes to the bottom of the risers. Every day I add about 0.5 liters of water and it should flow somewhere. I`m already wondering about the leakage of the primary exchanger, which would then lead to exhaust gases entering the chimney...

Hello.

zeppelin60 wrote:

The safety valve is located in the boiler casing and there is no outlet to the outside

There is a drain from the safety valve leading outside. Look from the bottom of the boiler. I marked it with a red arrow in the photo below:

zeppelin60 wrote:

The heating system for the domestic hot water tank is cut off because I do not use it: the domestic hot water is heated in a separate electric boiler (PV).

This is a very serious mistake. The valves between the boiler and the tank should not be closed, even if you do not heat hot water with the boiler.

One more question. After topping up the water, once the central heating system has warmed up, what is the pressure? Does it by any chance reach 3 bars or even slightly exceed them?

zeppelin60 wrote:

I`m already wondering about the leakage of the primary exchanger, which would then lead to exhaust gases entering the chimney...

Unfortunately, it is very likely that it does not go into the chimney, but flows out with the condensate.
After heating in the evening, turn off the boiler, wait an hour, check the pressure and top it up if it is too low (you can top it up to 1.5 bar), then remove the condensate drain pipe and put it in some container. The next day, before turning on the boiler, check whether something has flowed into the vessel and how much. Conduct the test in dry weather.

OK, the PSV drain is at the bottom, but the floor under the boiler is not flooded/moist.
The valves to the tank were always open, now the service technician closed them to exclude losses caused by the domestic hot water system.
During operation, the pressure remains approximately 1.2 bar. At night, the boiler turns off when the temperature reaches 20 degrees Celsius (22 degrees C during the day).
I read about this check through the condensate drain, I did an experiment like this before the service arrived, nothing flowed out after turning it off, but I will repeat it more carefully.
I wonder if I should cut off the system during the test and increase the pressure in the boiler itself?

We often look for the causes of leaks in the boiler and it is in the installation. When the central heating system is running, leaks may dry up quickly. We search very carefully, touching every pipe joint. Sometimes leaks appeared in the floor or wall. Eruptions appeared after some time

No need to prolong the thread: after various attempts I couldn't find a spot, but it seems to have stuck on its own (stone?), because now I only top up every few weeks. And it has to stay that way, the heating season has started, when something concrete comes out, it will be known.