If you own you own cylinder, you will know that regular maintenance is as simple as properly cleaning and rinsing, and storing it safely with some pressure in. It is still worth running through a few checks when your cylinder has been stored for a while.
If you rent cylinders, chances are they are in good working order. However, a quick check over is never a bad idea!
It can be a little annoying to turn up to a fill station, ask for a Nitrox fill, and be denied because your tank is past it’s test date! There’s an element of a walk of shame back to your car, and the embarrassment of telling your buddy!
The solution is easy though – check your stickers! Are they in test (Hydro/visual/O2)? Better still to set a reminder on a device a few of weeks ahead. Isn’t technology great?!
While your are looking over the stickers, check the tank for general wear and tear, looking for rust or bubbling paintwork. Signs of these indicate that a proper test and inspection is needed. If it has a boot you can remove, it is worth checking under there, and maybe loosening and moving any jubilee clips too, in order to get a proper look.
Look at the valve outlet and check for corrosion/debris. If there’s a light dusting, a toothbrush may be all that is needed to shift it.
Open the valve a little and check there is still pressure in the cylinder. This also pushes any loose debris out of the valve opening and clears it. If there is no pressure, then the cylinder needs servicing. Divers already know that you should never completely empty a cylinder, so if it was pressurised when it was stored, then you have a leak. You should assume an empty tank is contaminated, and it’s time for a service!
DIN valves: check the thread is ok, and after opening the valve quickly to blast out any debris, see if your regs screw in without needing effort. If it starts to jam, look at the valve opening again and also check the regulator’s DIN screw for damage or corrosion. If there is some light debris in the thread, a toothbrush or toothpick can clear it. DIN screws should never be difficult to attach!
A-Clamp: Check the o-ring and the contact area for damage. If it has a removable A-Clamp converter, get out your trusty 8mm allen key and remove it to check both o-rings, and the general state of the converter and valve outlet, as above.
Attach your reg set, and open the valve. Check that the gauge goes up nice and steadily, and remains solid when you breathe from the regulators. If the gauge fluctuates, you may not have the valve fully open, or there may be a restriction, or a problem with your reg first stage. Either way, don’t dive them! Identify where the issue is (i.e. cylinder or regulator) and get the problem part seen to by a technician. You can always consider hiring a temporary replacement to see you through your next planned dives.
Of course, it goes without saying (so we’ll say it here) that if you do find any issues, call your local dive centre to discuss with them. If necessary arrange to drop off your equipment for a technician to work on.
These checks are not exhaustive and in no way . They can be used as a part of your kit check routine. You should get your equipment serviced by a qualified technician!
Rich Frew, May 2020