Maintenance and repair of expansion tank

Maintenance of the expansion tank

• Check for external damage, corrosion, dents, and leaks every six months. If any external damage is found, identify and eliminate the cause.
• Check the initial pressure of the gas chamber Pг for compliance with the calculated value every six months. The initial pressure of the gas chamber can be calculated in the [Calculations] section of the website.
• Check the integrity of the membrane every six months and replace it if necessary.
• If the expansion tank is not in use for an extended period, store it in a dry room after draining all the water from it.

Checking the initial pressure of the gas chamber in the expansion tank. To check the initial pressure of the gas chamber, disconnect the tank from the heating system, drain the water, and connect a pressure gauge to the gas chamber nipple. If the pressure is below the set value, the tank should be inflated with a compressor (such as an automobile compressor) through the same nipple.

Checking the integrity of the membrane. If air is released through the drain valve during the pressure check of the gas chamber after draining the water and the pressure drops to atmospheric, the membrane is punctured.

Possible malfunctions of the expansion tank

Expansion tank repair. If damage to the membrane is detected during diagnostics, it must be replaced. Gluing the membrane is not recommended, as cyclic stretching-compression is destructive for glued connections.

Replacing the membrane

• Disconnect the expansion tank from the heating system and drain it.
• Reduce the pressure of the gas chamber through the nipple in the upper part of the tank.
• Remove the flange of the membrane located in the area of the flange for connecting the pipeline. Unscrew the nut in the upper part of the housing (if it exists) to release the membrane holder.
• Remove the membrane from the hole in the lower part of the housing.
• Check the inner surface of the housing for dirt and corrosion. If present, remove them and rinse the surface with water. Then dry the expansion tank housing.
• Remember, the membrane is not oil-resistant, so oil-containing substances should not be used for the anti-corrosion protection of the inner surface of the housing.
• Insert the membrane holder into the hole in the upper part of the installed membrane (if the fastening is provided by the tank design). Screw the bolt into the membrane holder, insert the membrane into the housing, and insert the holder into the hole in the bottom of the housing. Secure the membrane holder with a nut.
• Mount the membrane flange on the housing.
• Set the pre-pressure of air in the expansion tank. Check for leaks and connect the tank to the heating system.

Attention!

It is best to fill the air chamber with an inert gas, such as nitrogen.

Before removing the gas from the air chamber, drain the water from the tank.

The service life of the expansion tank is reduced at maximum values and overloads, as well as outside the specified temperature range.

Replacement of parts is allowed only with original spare parts from the tank manufacturer.

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