disconnection of radiators from the hot water boiler

Hello!
I have to replace the CO furnace and by the way I would like to redo my installation . My installation consists of a central heating boiler and a small boiler that heats the water in the boiler, it has no coil, i.e. the water that flows from the hot tap in the tap also comes from the small stove. The stove is tiny and heats up my water very quickly, I don't want to remove it until it is leaking. Of course, the CO furnace has a coil. My problem is that when I heat the water with a small stove in the summer, sometimes the heaters on the floor get warm. I would like someone to mark me on the diagram where I can install valves to avoid heat loss, and where to install valves to be able to heat only the boiler without radiators with the CO furnace.
1. BOILER WITH 4 CONNECTIONS 2 TO COIL 2 DIRECTLY INTO THE INTERIOR.
2. BOILER CO
3. THE SMALL HOT WATER STOVE
The four outputs in the corners of the diagram are the installation of radiators.

imt 579 wrote:

Of course, the CO furnace has a coil. My problem is that when I heat the water with a small stove in the summer, sometimes the heaters on the floor get warm

In this case, hot water from the boiler heats the water in the coil. This water then enters the radiators by gravity. The solution is to install a check valve on the coil supply. (Flow direction to the coil)

Close the valve on the coil supply. BTW. In such a system, it should be minimally open during normal operation, so that the rest of the heaters work properly on the pump (ruffling).
Nevertheless, the heat can return to the radiators by convection.
This hot water boiler is gas? Because, to be honest, I don't like the Polish tradition of smoking (smelling) in 30-degree heat in order to heat the water for a shower. The electric heater in the second tariff is a very convenient solution.

BANANvanDYK wrote:

Close the valve on the coil supply. BTW. In such a system, it should be minimally open during normal operation, so that the rest of the heaters work properly on the pump (ruffling).
Nevertheless, the heat can return to the radiators by convection.
This hot water boiler is gas? Because, to be honest, I don't like the Polish tradition of smoking (smelling) in 30-degree heat in order to heat the water for a shower. The electric heater in the second tariff is a very convenient solution.

A CO furnace is an ordinary fuel-fired furnace, currently it will have a capacity of 28KW. I do not have a shower at home, we bathe in a tub, here are more remains, as my friend called it Polish tradition.

I understand that I should put the valve in place marked 4 and then when I close it, the radiators will not heat up. This is also what I planned to do, because the installation in this place was always boiling. In my girlfriend's place marked 5, they have a valve installed that they close when they smoke in a hot water stove in the summer. When I install the valve in this way and close it, the central heating will only heat the radiators, do I have to do something else? Or maybe it is better to mount it behind the coil on the supply of radiators? I would like to redo this because when the small stove fails, I will definitely not invest in a new one, but I will want to enlarge the boiler to 300l and heat the water with the CO stove.

imt 579 wrote:

A CO furnace is an ordinary fuel-fired furnace, currently it will have a capacity of 28KW. I do not have a shower at home, we bathe in a tub, here are more remains, as my friend called it Polish tradition.

I understand that I should put the valve in place marked 4 and then when I close it, the radiators will not heat up. This is also what I planned to do, because the installation in this place was always boiling. In my girlfriend's place marked 5, they have a valve installed that they close when they smoke in a hot water stove in the summer. When I install the valve in this way and close it, the central heating will only heat the radiators, do I have to do something else? Or maybe it is better to mount it behind the coil on the supply of radiators? I would like to redo this because when the small stove fails, I will definitely not invest in a new one, but I will want to enlarge the boiler to 300l and heat the water with the CO stove.

I do not see the expansion vessel on the diagram? If it is not in the system, it is dangerous and it should be installed first according to the art, if it is, it should be marked on the diagram so that system modifications will not lead to its cut-off.

28 kW boiler fired to heat how many liters of water in the boiler? A single load is 2-3 kg of wood, and if someone places more, it will be a steam boiler at home? Who will watch over it? Cutting off the radiator circuit increases the danger in summer. Perhaps it is more profitable to install an electric heater for the second tariff, when the small stove is not fired.

At your own risk, in point 4, the installed non-return valve circulating towards the boiler and the cut-off circulation of the radiators in point 5 as shown in the diagram will reduce the losses, taking into account the above-mentioned conditions.

How is the small furnace (3) and the DHW circuit protected against excess pressure?

In my opinion, it is mandatory to have two valves on the coil, so that when replacing the boiler, you do not drain the refrigerant from the heating system. Unless it is at such a height that you do not need to discharge a large amount of heating medium.
With this valve no. 5 I would also be careful to install valves on the installation riser, so as not to cut off the expansion / safety pipe by accident and create a closed boiler-boiler system.
Unfortunately, but always somehow, when heating only the boiler by the boiler, the heat will be transferred by convection and gravity to the radiators. Unless the radiator system is completely cut off with valves, which will be burdensome in operation, in addition, the radiator system should, in my opinion, have additional venting with an expansion vessel (pressure in tightly closed radiators). Besides, you don't see one more threat. The boiler's power is 28 kW, and the coil's power is several kW. You sprinkle too much coal or ignite it too quickly and cook the system. Opening the radiators always helps to cool the boiler down.

imt 579 wrote:

I do not have a shower at home, we bathe in a tub, here are more remains, as my friend called it Polish tradition.

And also the old Polish tradition of disrespect for energy. Think about fitting a shower. I use about 7 liters of water in the shower, and it is technically possible to slide down to 5 liters. The 80-liter boiler is enough for two people, and there will be no trouble with servicing the third one.

The expansion tank is mounted as shown in the picture, there is only one automatic vent in the entire installation, the rest of the vents are half-inch pipes going to the attic, here also my next question arises, can I cut each of them above the radiator and install an automatic vent there?
I have a 140 liter water boiler, we currently live in 4 people, until recently we lived in 9 people. Our house was built in the times of the Polish People's Republic, the installation is over 35 years old with slight modifications, such as the CO pump and the plastic installation in the bathroom, plus one air vent, which I mentioned earlier. The boiler has a safety valve installed on the cold water supply, unless it protects against too high pressure.
The house has about 200m2, accessed by a garage with an area of about 70m with a stove and one large radiator, I do not know what it is professionally called, I have a PVC made of a 2-inch pipe braided with a corrugated window sheet, but there is no insulation for the building.
If he installs a check valve on the coil supply, the central heating pump will have the force to open it, is there no risk that the valve will jam or that more heat will go to the radiators? I would trust the manual valve more because even if I forgot to open it, all the heat would go to the radiators. I have a valve at home as in the attachment, but I think my friend is a valve under construction similar to the one I have at the central heating pump.
Isn't it better to install the valve in the place marked 6 instead? The pump would push all the heat from the boiler only through the coil and the excess pressure would go back to the radiators, wouldn't it work like that?

imt 579 wrote:

The expansion tank is mounted as shown in the picture, there is only one automatic vent in the entire installation, the rest of the vents are half-inch pipes going to the attic, here also my next question arises, can I cut each of them above the radiator and install an automatic vent there?
I have a 140 liter water boiler, we currently live in 4 people, until recently we lived in 9 people. Our house was built in the times of the Polish People's Republic, the installation is over 35 years old with slight modifications, such as the CO pump and the plastic installation in the bathroom, plus one air vent, which I mentioned earlier. The boiler has a safety valve installed on the cold water supply, unless it protects against too high pressure.
The house has about 200m2, accessed by a garage with an area of about 70m with a stove and one large radiator, I do not know what it is professionally called, I have a PVC made of a 2-inch pipe braided with a corrugated window sheet, but there is no insulation for the building.
If he installs a check valve on the coil supply, the central heating pump will have the force to open it, is there no risk that the valve will jam or that more heat will go to the radiators? I would trust the manual valve more because even if I forgot to open it, all the heat would go to the radiators. I have a valve at home as in the attachment, but I think my friend is a valve under construction similar to the one I have at the central heating pump.
Isn't it better to install the valve in the place marked 6 instead? The pump would push all the heat from the boiler only through the coil and the excess pressure would go back to the radiators, wouldn't it work like that?

Read about the rules for connecting the expansion vessel https://www.elektroda.pl/rtvforum/topic1900517.html, because you have it connected quite originally. Assuming a slight interference in the existing system, it is unacceptable to insert the valve in point 5 as shown in the diagram, because the vessel may cut off. When boiling water in the boiler, the excess pressure would be removed through the venting pipes in the attic, therefore their removal and replacement with air vents is possible only after changing the connection of the expansion vessel. In point 6, for safety reasons, I would not install any valve. As for the check valve, the pump should deal with the resistance, while the gravity circulation might not be enough, so it is advisable to use a check valve in such situations. At the boiler itself, on the branch from the riser pipe exiting the stove, you can install shut-off valves, but so that it is not possible to close the flow through the riser pipe. Closing the flow through manual valves is cumbersome, and may be applicable when it is done occasionally, e.g. at the beginning and end of the summer season, which may apply when a small stove is used in summer.

Yes, I meant a check valve, for example as shown in the picture.

So I will install the manual valve in the place marked as 4, I will open it when I use the CO stove. My problem with the expansion tank is connecting it to the return? From what I remember, it was connected backwards and the guest, when he transformed the bathroom installations into plastic, said that he converted it to me because they used to do the other way around, but now it's ok.
What and how to convert to create a small water heating circuit?

I do not know to what extent this installation diagram corresponds to the reality, but there are some errors here.
Generally, the installation was designed as gravity with an upper separation, adding a pump in such a system makes it necessary to get it working properly in the pumping system.
The main riser also serves as a safety / expansion pipe. In accordance with PN, it is unacceptable to install the so-called pump bypass.
The expansion vessel should be installed as close to the riser as possible. It does not have to be directly above it, because in principle it is necessary to close the safety pipe which is connected to the top of the expansion vessel. The expansion pipe is even better when it connects back to the radiators, only according to PN it must be 1 inch in diameter.
The installation does not need automatic vents, because the upper section is an installation that bleeds spontaneously in the gravity system.
The expansion vessel is not connected correctly in your installation. It cannot be far from the vertical, because the supply pipe goes with a slope, and the safety pipe (also used to vent the installation) should go up - on the vertical you are constantly getting an air plug that only a pump can push. Moreover, the safety pipe is not a vent! Must be connected to the top of the expansion vessel. Composite materials such as plastic and PEX must not be made of safety pipes.
A pump on a riser can increase the pressure on the riser so much that the water will overflow through the safety pipe into the expansion vessel, i.e. it will start to circulate like in a radiator. It would be different if there was a separate safety / expansion pipe and the radiators operated in a separate closed pump circuit vented manually or automatically.
The last issue is correct orifice on the radiators and boiler, because gravity always left full flow, and in the pumping system the pressure must be distributed over all radiators. Under gravity with a pump, the greatest flow goes through the closest heaters and the boiler, except that in order for the pump to start helping gravity, it must work at the highest speed. Therefore, these receivers must be muffled to increase the flow on the farthest receivers (by the way, the pump's revolutions will be lower).

They come back to the topic. Valves are necessary on the coil, on its supply a valve with an ordinary "tap" and a built-in vent that can be hidden on the pump (just unscrew it for e.g. one turn), and on the return a cut-off ball valve, which will be useful when disconnecting a leaky boiler. In terms of cooling down, a flap valve or even a simple mushroom head valve without a spring is a bit of a moot point, maybe read my topic where the idea of changing the coil supply connection point is. This, in combination with manual closing of the supply valve, should effectively prevent heat from escaping from the boiler, because by gravity there will be no way to escape down.

This is what it looks like in reality, I have not yet drawn the entire installation, but I think that what is most important I have shown, the pipes of course fall towards the boiler. I just don't remember how many pipes are led to the attic from the radiator in the right corner of the diagram, possibly only one, but possibly two. In one of the rooms that I have not marked, there are two led out, and in one only one.