The seal, position 21, is a small but key part of the Elecro G2 heat exchanger. It is placed under the plug of the flow flap (position 20) and forms a sealing layer between the plug and the exchanger body.
Without this seal, the plug would not provide a watertight closure of the service opening and the exchanger would leak water. Replacement is recommended whenever the plug is removed, that is, during every service intervention in the area of the flow flap.
Although it is a small and inexpensive part, its absence or wear can cause a visible water leak from the exchanger and a forced shutdown of the pool heating.
