i ordered a new valve for my 75 cu.ft. tank. what can i expect for difficulties when i try to remove the original valve?
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valve change out on Omega tank
- Thread starter tsmith
- Start date
That’s a good question. The valve is of the straight thread type with a flange and O ring for sealing. The valve should not be torqued very hard, but... you never know who installed yours. Some valves have an area on it for a wrench to fit (wrench flats) and if necessary attach a wrench and sit on the tank and un do it or have someone hold it for you. It SHOULD come off though.
Once removed be sure to look inside your tank to see if there’s any debris or water or moisture. Perhaps lower a small flashlight on a string or straightened out coat hanger to see better. Clean as necessary. Drying the tank if wet is another matter, PM me if that’s necessary.
Once ready to install valve make sure threads are clean with a new or old tooth brush. In the scuba business our valves were chrome plated brass and we put a dab of silicone grease on the threads to prevent galvanic corrosion. The valves we always saw on fire service SCBA’s were anodized aluminum, it really isn’t necessary to grease them but it won’t hurt anything. If it was my tank, I wouldn’t bother with grease, it just isn’t necessary on like materials.
You should put some silicone grease on the O ring. All that’s needed is to make the O ring shiny, no globs of grease. Put a tiny bit on your fing tips and then rub it on O ring. Excess lube won’t hurt but isn’t necessary.
Thread valve into tank and turn it till it’s shoulder meets the tank and then with your hand only, confirm the valve is in all the way and that’s it.
If there valve doesn’t shoulder on the tank and there is a small gap, the O ring could extrude under pressure and all the contents will leak out. Other than a pop as the O ring is extruded your only danger is that an invisible high velocity, high pressure stream of air that can pierce skin, which can be serious.
Hopefully you got a valve with the proper thread as there are SAE and metric threaded valves.
Best of luck.
Randy
Once removed be sure to look inside your tank to see if there’s any debris or water or moisture. Perhaps lower a small flashlight on a string or straightened out coat hanger to see better. Clean as necessary. Drying the tank if wet is another matter, PM me if that’s necessary.
Once ready to install valve make sure threads are clean with a new or old tooth brush. In the scuba business our valves were chrome plated brass and we put a dab of silicone grease on the threads to prevent galvanic corrosion. The valves we always saw on fire service SCBA’s were anodized aluminum, it really isn’t necessary to grease them but it won’t hurt anything. If it was my tank, I wouldn’t bother with grease, it just isn’t necessary on like materials.
You should put some silicone grease on the O ring. All that’s needed is to make the O ring shiny, no globs of grease. Put a tiny bit on your fing tips and then rub it on O ring. Excess lube won’t hurt but isn’t necessary.
Thread valve into tank and turn it till it’s shoulder meets the tank and then with your hand only, confirm the valve is in all the way and that’s it.
If there valve doesn’t shoulder on the tank and there is a small gap, the O ring could extrude under pressure and all the contents will leak out. Other than a pop as the O ring is extruded your only danger is that an invisible high velocity, high pressure stream of air that can pierce skin, which can be serious.
Hopefully you got a valve with the proper thread as there are SAE and metric threaded valves.
Best of luck.
Randy
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I am assuming you have a U.S. made tank with a fireman's valve that you want to replace. The valve will not move unless the tank has no air pressure inside. Most fireman's valves are rather difficult to remove with just a twist. You can remove the valve with an adjustable wrench strap which has a handle in order to keep the tank from slipping. Use this in conjunction with a rubber headed mallet. You could also use a large crescent wrench tightened over the narrowest portion of the valve. Hitting the base of the wrench with the mallet will provide leverage to knock the valve loose. The wrench could mar the valve you're removing so you may wish to place a rag over the valve before applying the wrench. I've always been able to just rap the valve itself with a rubber mallet to break the valve loose.
If your tank came from China it's an M18*1.5 threaded valve. If it's from the U.S. or Korea it's a 7/8-14 thread. Make sure your valve thread is compatible with your tank thread. A 116 buna o-ring will seal a 7/8-14 threaded valve to the tank with a just firm hand tight fit. I use silicone grease on the o-ring and the threads. Just be sure there is no visible gap between the valve and the tank or a full pressure tank fill will force the o-ring to fail.
If your tank came from China it's an M18*1.5 threaded valve. If it's from the U.S. or Korea it's a 7/8-14 thread. Make sure your valve thread is compatible with your tank thread. A 116 buna o-ring will seal a 7/8-14 threaded valve to the tank with a just firm hand tight fit. I use silicone grease on the o-ring and the threads. Just be sure there is no visible gap between the valve and the tank or a full pressure tank fill will force the o-ring to fail.
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I wrap my scba in a rubber floormat and secure it to my workmate portable workbench with two ratchet straps. I then am able to get a big crescent wrench on a flat spot to break the valve free. Looking at a picture of an Omega, it looks like the valve is knurled and round with no flat spot and has the gauge and pressure relief valve in the side of it. You might have to remove one or both of those to have enough room to get a tool on it, maybe something like a water pump plier with a little rubber or leather around the knurling so not to mark it.
The workmate table opens up in the center so I open it enough to allow the cylinder to nestle in the opening, then secure with the straps. The rubher floormat protects the finish on the tank and provide friction so the tank will not turn.
The workmate table opens up in the center so I open it enough to allow the cylinder to nestle in the opening, then secure with the straps. The rubher floormat protects the finish on the tank and provide friction so the tank will not turn.
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As Humdinger above said, a rubber mallet is your friend with this. A good rap on the wrench with break the seal loose a lot easier than just pulling on the wrench. A little silicone on the new o-ring will ensure it doesn’t bind and tear on reassembly.
Upvote 0