What exactly is a "valve service"

[crawford]

Just bought my first used tanks, and the seller suggested I get the valves serviced. When I asked the place that will hydro and vis my tanks if they serviced valves, they acted like I was strange (I think the person on the phone said something like "What, see if it will open and close?"). This place does hydro, visual inspections, and air fills, but is not a Dive shop.

They then suggested I call the LDS, and I soon realized this may be outside their experience.

My question is, what exactly is a valve service? I don't want to get talked into buying a new valve, if the one's I have are fine and only need to be checked, oiled, burst disc replaced, or whatever should be done.

Thanks in advance.

 

[neil]

A valve service is a cleaning and rebuild of the valve. The parts replaced are the seat (if needed), stem packing rings, bonnet seal/o-ring, neck o-ring, face o-ring and burst disc if needed.
The valve should work smoothly. It should not leak from anywhere in the open or closed position. If it leaks from the stem when open it's the valve packing. If you have to crank on it to close it, it's the seat. I usually replace the burst disc with the hydro.
Basically, if it ain't broke, don't fix it, IMO

Neil

 

[Rick Murchison]

On deco bottles, whenever I deem an O2 cleaning due I'll include a valve rebuild. Otherwise, if the valve works smoothly and doesn't leak I don't mess with it.
Rick

 

[FredT]

A valve and tank visual inspection is a good thing. Since a burst disk should not be re-installed if the plug is removed that part needs a change any time it comes out. The rest of the valve simply needs a visual and cleaning if necessary. All parts for a FULL valve rebuild are under $10, there is only one "special" tool necessary (a slotted 3/8" face screwdriver) necessary to remove the handle, and about 5 minutes labor not counting the time spent cleaning.

This gives the valve and tank a baseline for you to gauge future maintenance needs since you don't know what treatment the thing had before you got your hands on it.

FT

 

[crispos]

Our LDS also tapes the old valve parts in a baggie to the tank, so the customer can see what was changed. You might ask them to do that, and you tell them straight, so you can understand and see what parts were changed.

 

[redacted]

The seat in that valve is similar in material and function to the seat in a 1st stage. Except the valve seat cycles once during a dive, while the 1st st seat cycles hundreds of time in that same dive. If it ain't broke, don't fix it

 

[crawford]

Thanks, guys. I got the tank hydro'd, vis'd, and filled, but left the valve well enough alone (tested the valve opened and closed smoothly before taking it in.).

Took it diving to a very shallow quarry recently and it works fine. Thanks for the peace of mind you guys gave me.