Ever wonder why you should get your tank valve serviced annually? Well here’s your answer – I took this high pressure (HP) seat out of a tank valve that appeared to be working fine, it turned freely, sealed well, put a reg or test gauge on the cylinder and it’d show full pressure. The problem occurred when you tried to breathe from the cylinder under workload, gas flow was intermittent and would only allow limited volume through the valve – deadly at depth!
The HP seat shown in the image above is a critical part of a valve – it’s what make “lefty loosey, righty tighty” work. If worn out from usage, or as in this case completely blown apart, your valve will fail. A valve service is relatively cheap exercise and can be done anytime; it’ll also keep your tank in working condition and could just well save your life on day!
Incidentally, whilst I’m on about tank valves it’s propbably worth mentioning that regular maintenance is you friend. Turning the handwheel in fresh water after a dive is all that is need. I’d also recommend you avoid picking the cylinder up via the handwheel directly as this tends to bend the shaft spindle and causes all sorts of spinning problems.