It's down to the quality of packing in the coil. The only thing that stops the egress of liquid is the cotton. If this is not substantial enough to stop leaks once saturated, it's a dud. It's an unfortunate side effect of the necessary design to accommodate a tanked system. The newer types of coil are a different design, the coil is wrapped in a vertical spiral rather than a horizontal spiral as per my previous subtank. Mine leak intermittently, if it gets unbearable I change the coil. Sometimes it's a good one and holds the liquid better, sometimes it's a dud.
It's down to the quality of packing in the coil. The only thing that stops the egress of liquid is the cotton. If this is not substantial enough to stop leaks once saturated, it's a dud. It's an unfortunate side effect of the necessary design to accommodate a tanked system. The newer types of coil are a different design, the coil is wrapped in a vertical spiral rather than a horizontal spiral as per my previous subtank. Mine leak intermittently, if it gets unbearable I change the coil. Sometimes it's a good one and holds the liquid better, sometimes it's a dud.