Leaking valves...

[Aeryck]

anybody ever fill up their tanks, remove the and replace the fuel hose and have gas hissing out of the filler neck? It hasn't happened before, I am wondering if it may be something that happens now and again from being under 10 degrees outside or if the part needs replacing.

[CNG Utah]

Re: Leaking valves...

I've had it happen to me a couple of times in different vehicles. It's always been on very cold days. I think some moisture gets trapped in the fill nozzle and freezes it open. It usually squirts for a few minutes and then closes again.

[Curtis]

Re: Leaking valves...

Ice does tend to form in the fill nozzle during very cold weather. Try reconnecting the hose & disconnecting again a couple of times until the ball valve seats. If this occurs in warm, dry weather it's usually dirt that's gotten under the ball seat. Try the same thing and make sure to keep a fill nozzle cover in place to protect this from happening.

[Amfuel]

Re: Leaking filler valves.

I need the size number of the vehicle receptacle O-Ring.

I have been scouring the site to no avail.

Thank you

[Amfuel]

Re: Leaking valves...

Bumping to refresh

[Amfuel]

Re: Leaking valves...

Here is the info on the receptacle Oring.

You can get 100 of them off of McMaster Carr (www.mcmaster.com) for $7.00+shipping. Total is like $12.00.
Part number 9452k22

Another bit of info on the receptacles (and nozzles) is to spray them with a silicone lubricant occasionally. If you can find a dry silicone spray that is recommended. (Especially before the cold weather sets in.)

[cowboy]

Re: Leaking valves...

I would worry about water in my fuel if ice is forming as cng wont freeze is the dryer working water is bad for the whole system

[Highmarker]

Re: Leaking valves...

cowboy,

My understanding is here in Utah they don't use dryers. They claim that the natural gas pulled out of the Wyoming and Utah is dry enough to not require dryers. There is a reason why CNG systems have filters prior to high pressure regulators. The filters need to replaced every so often. That doesn't say anything for the check valves. Studies have been done on the water vapor is natural gas and its affect on the tank, but not significant damage has been detected.

[cowboy]

Re: Leaking valves...

well if we got rid of the water vapor than whould my tank be good for say 15 1/2 years as any damage is significant when dealing with this kind of pressure rule # 1 water is bad rule # 2 if you think water is good go back and read rule # 1LOL

[Amfuel]

Re: Leaking valves...

Here is the skinny on water in natural gas.

Normal pipeline gas has 7 lbs of water per mm cu/ft. At low pressure that is fine. When you compress the gas the water content needs to be 2 lbs per mm cu/ft or less. The compression phase will condense excess moisture out. That is why the Phill (and other systems) have the coalescing filter. They not only remove impurities but absorb that 5 lbs per mm cu/ft or so of water from the CNG.

In Utah that may work OK if you have excess moisture. Your vehicle filter will collect some and the rest will pass through to the combustion chamber.

In the northern climate the excess moisture will turn to ice and your vehicle will not start when the temperature drops below 18 degree F. The moisture in the gas freezes during decompression at the regulator and will effectively block the fuel line. (if you run bifuel you can start on gasoline and switch to CNG once the engine warms up) If there is any leaking at the nozzle/receptacle connection the same issues arise. There is decompression at the point of the leak causing icing and can block the check valve in the receptacle from closing properly.

Here in WI I have years of industrial maintenance experience and even with low pressure gas the utility will clean up the gas to prevent issues of moisture and also remove the butane and other ethane components with the higher condensing points. With the gas line buried typically 18" and the frost line reaching as deep as 4' moisture and other components of the gas such as butane will reak havoc on supply reliability.

So the bottom line on fuel stations serving up wet gas that is dry enough for Utah is OK i guess, just don't plan any winter time trips to colder climates unless A. You have a bifuel vehicle Or B. You have your AAA card along.

[wessneed]

Re: Leaking valves...

I am very new but own a cng, so was wondering are these valves serviceble, and if so how do you get the pressure of them? It would seem fill valves would have pressure at all times.

[siai47]

Re: Leaking valves...

The Fill port is somewhat able to be serviced. In most installations there is a second check valve between the tank valve and the fill port. So, the tank valve, the check valve and the fill port provide a means to keep the high pressure fuel from escaping from the tank. However, as noted in this thread, all can fail (usually due to freezing) and allow leakage. Unless you know the way the system works, how to bleed the residual pressure from the lines and how to handle the various "O" rings and face seals used in the pipe fittings, it would be unwise to attempt to work on the high pressure side of the system. If you are getting leakage from the fill port (in warm weather) the amount of fuel that leaks (i.e. seconds before the leak stops) would give an indication if the problem exists beyond the fill port.

[fchanes]

Re: Leaking valves...

I have a 98 contour that free flow through the receptacle. Can someone point me in the right direction to get this fixed. Thanks.