Ariston T2 Boiler Pressure Increases with Heat Level - Radiator Replacement Query

Hi

Ariston T2 dual-function oven. When idle, the stove shows a pressure of 1 BAR in the heating system. After turning on the heating and setting the heating level (3), the pressure increases to 2.2 BAR. When increasing the level (approx. 6), the pressure indicator shows a warning condition (red field). In the last heating season, max. even with the heating value (7) it is 1.8 BAR.

1. I wonder what could be the reason for this...??? Why does blood pressure jump so dramatically? The water pressure in the system at rest does not exceed 1 bar (installer`s recommendation) and suddenly increases when the heating is turned on.

2. Do you recommend replacing old cast iron radiators with new metal ones?
Will you be able to save $$$ in the process? Is it just cosmetic...

3. What pressure should be in the heating system? so that the stove operates as "economically" as possible.



Regards.

Hello.
1. Lack of air in the central heating expansion vessel
2. If the installation and radiators are clean (not clogged), such replacement does not result in radical heating savings.
3. Pressure has no effect on savings. However, it is very important for the proper and reliable operation of the boiler and installation. With a cold installation it should not be lower than 1 bar, and recommended is about 1.2-1.3 bar. After the installation warms up, the pressure will increase slightly. Too high a pressure increase indicates a lack of air in the expansion vessel, damage to the vessel, or too small a vessel in relation to the water volume of the installation.
Regards.

Rysio4001 wrote:

Hello.
1. Lack of air in the central heating expansion vessel
2. If the installation and radiators are clean (not clogged), such replacement does not result in radical heating savings.
3. Pressure has no effect on savings. However, it is very important for the proper and reliable operation of the boiler and installation. In a cold installation it should not be lower than 1 bar, and recommended is about 1.2-1.3 bar. After the installation warms up, the pressure will increase slightly. Too high a pressure increase indicates a lack of air in the expansion vessel, damage to the vessel, or too small a vessel in relation to the water volume of the installation.
Regards.

Ad.1 Is a layman able to do something about it? (so far I have replaced the cracked combustion chamber cover and cleaned the electrodes). What could be the cause of "lack of air in the expansion vessel"? Maybe a little How To Thank you for your professional answer.

The lack of gas in the vessel is basically caused by two things:
- valve failure
- damaged (ruptured) diaphragm
In the first case, it is enough to replace the valve and pump air to the appropriate static pressure. In the second case, unfortunately, it is necessary to replace the vessel. The method of checking and possibly replenishing the air has been described many times on the forum. Look for.

Hello.
Ad 1. As fellow service technician73 wrote, the reason for the lack of proper gas pressure in the expansion vessel may be a fault in the vessel itself or the valve. There is an ordinary short car vent.
However, it does not have to be a vessel or valve failure. If the gas pressure in the vessel is not controlled and replenished, a natural phenomenon is the loss of gas over time, and after a few years, sometimes even its complete absence.
First, inflate the vessel, check the valve for tightness (if not tight, replace it), and observe what happens next.
Regards.

Hello, I would like to join the topic. Namely, my furnace is a single-function Ariston Micro system B11bs with a 125l domestic hot water tank and I still have the problem despite replacing the vessel with a new reflex type [but it has been in the garage for about 4 years], not used, and even though I pumped air into the vessel at 1.5 bar and after connecting everything, the pressure continues to increase, I thought that at the beginning when starting the new vessel it would be better, but there is no change, the vessel is more or less the same capacity as the old original one, I don`t know what else I can come up with, please advise.

ricki72 wrote:

that I pumped air into the vessel at 1.5 bar

Why so much ? What is the installation height?
Typically there is no need for more than 0.8 - 1.0.
The fact that it is growing is not a bad thing because the pot should work!
Pressure increase to approximately 0.5 bar below the activation of the safety valve at maximum heated water in the central heating.

What is the installation height?

The furnace is in the basement at 0 and + 1, there are distributors and the highest radiator is in the attic

Unfortunately, the pressure gauge shows 1.2 bar when cold, and when it starts to heat up, it increases to 3 bar and then releases the safety valve. Is it possible that something else could cause such an increase in pressure?

Too much pressure in the vessel. The correct pressure is 1.0 bar.
Of course, we check and correct the pressure without pressure in the central heating system, i.e. with drained central heating water!
If the vessel is in the boiler and it is possible to shut off the boiler, we shut off the boiler and drain the water, and only then do we take care of the vessel.
Then you add water to about 1.3 bar in cold water.
If the vessel is good, the pressure may increase slightly when heated, but certainly not enough to trigger the safety valve.

dareksin wrote:

Too much pressure in the vessel. The correct pressure is 1.0 bar.

Are you sure ?
There are no certainties here, only calculations.

Of course, only calculations. But ...
But regardless of the calculations, what can be the pressure in a vessel where the height of the installation does not exceed 10 meters?
I`m constantly learning, I`ll be happy to find out if I have any gaps in my knowledge.

You can use Google or other sources.

Thank you. With this approach, this forum can also be disabled...

dareksin wrote:

Thank you. With this approach, this forum can also be disabled...

Exactly, apart from that the electrode pops up every time, I see that on all MOD.-ele forums they are so nice and understanding :|

And when it comes to my spelling, I try my best,

Mr. Moderator;
ps
I`m struggling with the idea you gave me and I`ll describe everything in a moment;

dareksin wrote:

Thank you. With this approach, this forum can also be disabled...

In your signature you wrote about yourself: "Gas Heating Devices Service", so you should know it just like the multiplication table, and share your knowledge with people who don`t know anything about it, right here on the forum.

mirrzo wrote:

and share your knowledge with people who don`t know anything about it, right here on the forum

I am not the author of this thread.
I have the knowledge I have and I want to share it with others (anyone who wants to talk).
If I gave wrong advice, I`m waiting for a correction, not a referral to Google.
Otherwise this forum loses its meaning.

Exactly as my friend wrote, where there are two Poles there are three opinions, :D

But to the point; I drained the water from the expansion vessel, reduced the pressure in the vessel to 1.0 bar, then allowed water into the system to 1.2 bar [cold], turned on the stove and the pressure increased while heating the water to 2.2 bar in about 45 minutes, and at 65°C it leaked from the safety valve, when the water heated up and the stove turned off, the pressure dropped from 2.2 to 1.7. After turning on the second central heating function, the pressure increased to 2.0 bar again and within 45 minutes it reached 3.5 bar and then I turned off the stove, so I have no idea what happened, I will also mention that after removing the vessel, I rinsed it several times with water under pressure, and before turning on the stove I bled all the radiators

Does anyone have an idea what could have happened? Just please do not refer me to other sources of information.
Thank you in advance

And I see that this vessel needs to be replaced. Your diaphragm is gone. The only solution is replacement. After the procedures and symptoms you described, this is the only possibility.

Out of moderator duty:
Please follow the forum rules and regulations. Begin sentences with a capital letter.

Hello.
Friend ricki72, I read in your posts that you changed the diaphragm vessel and the problem did not disappear. Moreover, from your statements it is not clear which expansion vessel you replaced and pumped - central heating or domestic hot water.

Assuming that you have replaced the central heating vessel and it is properly inflated, it can be assumed that the vessel is functional, but this is not a certainty.
Write down the capacity of the vessel and installation. Maybe the dish is too small.
Check the patency of the connection between the vessel and the system - obstruction may cause such a problem.
I once had a case where an unused vessel that had been left uninstalled for several years did not compensate for the pressure, despite the tightness of the membrane and the correct pressure. It turned out that the membrane, pressed with air to the tank, stuck to it and did not work.

Do another test:
Set the pressure in the vessel again to 1 bar, while there is no water in it, and then set the pressure in the central heating system to 1.2 bar. When inflating the vessel, note that the vessel has retained the gas pressure at the last time you inflated it. If so, this indicates that the vessel is tight.
Then start the boiler and when the pressure in the central heating installation increases significantly, measure the gas pressure in the vessel. It should be the same as in the central heating installation. If it is the same as you inflated, i.e. 1 bar, or is much lower than the pressure in the installation, the connection between the vessel and the central heating system is blocked. If the pressure in the vessel is equal to the pressure in the installation, then the vessel is too small or water is being allowed into the installation in some way - this could be evidenced by the following: after the boiler and installation have cooled down, the pressure in the installation does not return to its initial state, but only is higher (I found such information in your statements).
Regards.

ricki72 wrote:

Does anyone have an idea what could have happened?

What is the capacity of the heating system and what type of vessel have you installed?
If you can pump air up to 1 bar, the membrane is intact. It seems to me that your central heating system vessel is too small.

dareksin wrote:

I have the knowledge I have and I want to share it with others (anyone who wants to talk).
If I gave wrong advice, I`m waiting for a correction, not a referral to Google.
Otherwise this forum loses its meaning.

I typed in Google: selection of expansion vessel, pattern, and a lot of this came up https://www.google.pl/search?q=dob%C3%B3r+nac...+przeponowego+wz%C3%B3r&ie=utf-8&oe=utf-8&aq= t&rls=org.mozilla:pl:official&client=firefox-a
To want is to be able.