I doubt whether it is worth installing an expansion tank for an indirect heating boiler

An expansion tank for the heating system is a necessary thing that can protect the weak link from rupture systems, if the pressure rises to a critical value, the safety systems will not work, or if they absence.

But in the hot water supply system, expansion tanks are often also installed, but there are a lot of different opinions about them. Basically, of course, those who do not have them, or they are of poor quality, speak out - they scold that they have wasted money. Or they argue that everything works fine anyway.

Water, which becomes unnecessary when heated and expanded in the water supply system, comes out through a special valve. So that it does not drip on the floor, it is discharged into a tube and then into the sewer. I don't even want to imagine that I have something dripping on the floor in the boiler room - although it is in my basement.

For me, of course, it is much better and safer to install an expansion tank. Excess water will go into it when heated. After all, the water supply system is constantly replenished with new water from the gas pipeline.

The difference between the tank for the hot water system can be seen externally - it is not red, but blue, or metallic. I have it, just metal outside. And the internal difference lies in the fact that the membrane in it is made not of technical rubber, as in a heating tank, but of food grade, because water is also used for food.

But it should be understood that the expansion tank requires periodic maintenance, because this is a rather serious and complex equipment. In addition, it must have a volume of at least 10% of the boiler volume. That is, if the boiler is 100 liters, then next to it is another capacity of 10 liters.

I have an expansion tank installed at the outlet of the water heater. On a hot water pipe. It's easier, you don't need a tee with a tap to drain the water. Before use, you need to pump air into the tank through a special nipple.

I must say right away that my heating and hot water supply system was serviced by the company that installed them for me for two years. This is their service, it is free, twice a year. But even now I am not going to refuse their services, although they are paid. There is no desire to climb into this system, especially since wear and tear appears every year and something needs to be changed, something to clean. Therefore, I prefer to entrust specially trained people.

The main thing is that I understand what and how it works and have never doubted the need for all the solutions that they offered me at the system design stage. Including the need for an expansion tank for the hot water supply system.