We remove the water intake unit from the column body.

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The efficiency of the water heater has noticeably decreased: when the burner is operating normally, the water heats up much less.
Weak pressure at the outlet of the column with normal pressure at the inlet. Water cannot break through the channels blocked by scale.
Cleaning the water intake unit
The water intake unit is installed at the entrance to the water supply system of the column, has a mesh filter to prevent clogging of the heat exchanger tubes with large particles of rust and sediment, as well as a membrane for automatic gas supply when the water tap is turned on.

After unscrewing the connecting screws, we open the case.
We clean the filter and rinse it with a strong stream of water.
We check the membrane. The membrane should be flat, if the rich people data has a pronounced concavity, it means that it has exhausted its resource and is subject to replacement. You can replace the "native" membrane of the old column with a modern silicone one, which has a much longer service life.
We close the cover of the water intake unit, "bait" the screws and tighten diametrically opposite pairs of screws in turn. This ensures uniform tension of the membrane.
Cleaning the heat exchanger
Disconnect the water inlet and outlet pipes of the heat exchanger. If the heat exchanger is not cleaned regularly, the fastening nuts may be clogged with scale, preventing their disconnection. In this case, we recommend using a special liquid WD-40, which can be purchased at any auto store. It is necessary to drip the liquid into the nut joints using an oiler. You can also use "Silit" for scale. After 15-30 minutes, the nuts can be unscrewed. If this does not work, try "tapping" the nut from all sides.
Having disconnected the heat exchanger, pour a descaling agent into it using a funnel. A solution of 100 g of citric acid per 0.5 l of hot water is perfect for this purpose. You can also clean the heat exchanger with nine percent table vinegar diluted with water in a ratio of one to three. But it is not recommended to use hydrochloric acid, as it can react with the metal from which the heat exchanger is made, which will only make the situation worse. Leave the solution inside the heat exchanger overnight.
Drain the solution thoroughly. If you do not remove the scale that has come off the walls, it can clog the heat exchanger tubes, so wash the heat exchanger with a strong stream of tap water. You can use tubes of the appropriate diameter for this.
We put the washed heat exchanger back in place, tighten the mounting nuts, having first changed the sealing gaskets.
Removing soot and carbon deposits