The function of the puncture pin is to pierce the charger seal. During this operation, the neck rubber surrounds and seals the charger neck, allowing gas to flow only towards the inside of the siphon. Both components are subject to high thermal shock, as they freeze immediately when the charger is pierced. The needle is made of hardened steel.
After several uses, the needle may become dull, bent or its end can break off. In this case, the cartridge will not be able to be pierced or will not be pierced in the correct way, so in extreme cases gas will escape from the inside of the charger as it is removed. It is always a good idea to replace this part during maintenance.
There are two types of puncture pins and neck rubbers available to buy. It is important that you pair them correctly. The longer blue rubber should be used for the longer pin. For short pins, use the shorter, black rubber.
The difference is because the fact that the redeemable chargers had a more inwardly positioned seal than the disposable chargers that have been on the market since 2018. The use of redeemable cartridges was made possible by the use of a long needle and all siphons were originally equipped with one. When changing to disposable chargers, the change in the sealing element would have caused the long needle to puncture the charger before it was sealed, so it was necessary to introduce a longer neck rubber to seal the charger’s neck sooner.