CNG regulator leak

[Marrigoround]

I’m on my fifth tank of CNG and after I switched out and opened the valve there was a huge flush of CNG leaking out of the regulator. Because I’ve never had so much as a small leak before I wonder if this tank could be over pressurized to a point that the regulator can not handle it. The pressure gauge on the regulator goes to 3,000psi but new tanks tend to start out at around 1,800. I’m unable to gauge the pressure on this new tank because of the massive amount of leaking.

I disassembled each fitting on the regulator that I could and retaped with yellow gas tape and the problem persists.

I sourced the last four tanks from the same vendor where one of them had a rotten valve handle so my confidence in the vendor is low.

Anybody have any experience with anything like this?

 

[smokey73]

Marrigoround, where are you sourcing your filled CNG tanks? My source is no longer doing it and I can't find a CNG station where I can fill my existing tanks from anywhere near us in Beaufort SC. I think I have a spare CNG regulator that I got when I purchased a spare tank from someone who was converting to propane. Send me a pm and maybe you'd like it.

 

[nfg2u]

How old is your regulator? You should have 2 regulators, a high pressure and low pressure. I had to replace mine (both) due to age and corrosion. They no longer made the one I had. I sourced info on Parker’s website and found the high pressure valve that I needed. Your high pressure valve should be rated much higher then the tank should be able to supply. I also fill my own tanks at a service station that has a auto vending system. I can fill two tanks for under 5 dollars.

The high pressure regulator is not cheap. I purchased a new one on eBay for around 150 dollars.

Pull both regulators and give them a good inspection, once the internal parts have worn out there is really not much you can do besides get new ones. A local gas shop might be able to test the high pressure regulator for you. The low pressure regulator is around 10-15 dollars.

Let me know if you need any more info.
Steve

 

[Marrigoround]

Thanks guys.
Smokey - I am in San Diego and source my tanks from Dana Point (1 1/2 hour drive), so I get two at a time. Cost ~$30 per tank with a one-time ~$150 per tank deposit. It took me a long time to find this place. They market for all of Southern California and I'm not sure they get much business. I'm worried they too will close up shop.

I'm really not sure if it is a problem with the regulator as the issue started with the new tank. It worked fine when I ran out the gas of the old one then 10 minutes of install later and it's all of a sudden too old? Seems weird. Do you know if your spare regulator is a low or high pressure regulator?

nfg2u - I would imagine that my regulator is original from 1987 and have no idea if it is a low or high pressure. There are two stages to the system meaning it has two regulator looking pieces attached together with a gauge on top of the first one. I did disassemble as much of it as I could and felt comfortable with and everything looked pretty decent and intact as far as I could tell.

I was originally thinking of going the route of self filling, but I'm not too comfortable with my knowledge on the subject to be fussing around with a high pressure flammable. Safety first. I figure that the system I have now is temporary as I will be begrudgingly switching over to LPG. If I can't solve this immediate problem, that might be happening sooner than later.

 

[smokey73]

Dana Point is a little far away for me (about 2000 miles) so I'm out of luck there.

 

[nfg2u]

I think you could replace both for less than $200 with some shopping. Its a simple system and should only have a supply hose and discharge hose. I believe its safer than LPG. Finding CNG, well thats another problem altogether. I decided to buy an auto adapter and fill my own CNG tanks.

 

[Marrigoround]

I'm not too confident on anything that I have found online because nothing looks like the regulator that I am using. I called a local gas company and they told me that these tanks should be filled up to 2200 psi, which is a federally regulated (DOT) pressure for this gas and that a regulator should be easy to find. Still not sure where though.

 

[smokey73]

I'm not too confident on anything that I have found online because nothing looks like the regulator that I am using. I called a local gas company and they told me that these tanks should be filled up to 2200 psi, which is a federally regulated (DOT) pressure for this gas and that a regulator should be easy to find. Still not sure where though.

I'll send you a picture of what I have on my boat and what I have as the spare and you can decide. It will be this evening though as I have to go to a meeting

 

[nfg2u]

High Pressure Valve that I purchased. Works great! Check the specs (Part # Parker Veriflo IR4001S1k4PXX4B, IR4000 Series)

MAXIMUM INLET PRESSURE (PSI)
4000 psi PCTFE seats only, 1250 psi PEEK, Vespel Seats

BURST PRESSURE
12,000 psig (828 barg)

Parker Valve ir4000
http://ph.parker.com/us/17554/en/single-stage-general-purpose-pressure-regulator-ir4000-series1
This PDF explains the part # and has all the specs as well.
https://www.parker.com/literature/Veriflo/Veriflo - pdf files/25000226_IR4000.pdf


I bought mine on Ebay, but I had to be patient as I didn't see them very often. I paid 95.00 US and the valve was brand new in sealed package.

The low pressure valve can be purchased at any BBQ supply company. Its a low pressure regulator, very common. You could replace the lines while your at it. There should be a supply line to the stove and one to the overboard discharge if it was installed correctly.

Hope that helps.

 

[Marrigoround]

A picture is worth a thousand words. I think that it is the brass piece that is leaking. All the yellow is new gas tape that I installed last night. Can you see any other obvious reasons for failure?

 

[nfg2u]

Yes I had leaks also, mix some dish soap and water and spray it with a spray bottle all over the regulator and the fittings. The leaks will bubble and you will be able to see what is leaking. That is one way to know where they are coming from. I doubt its the fitting to the tank.

Steve

 

[Marrigoround]

Wow, thanks for all the info. It's interesting to see how the shape has evolved. Is that the piece meant to replace just the brass section that I have or the whole thing? I also read something about an overboard discharge and do not think that I have one installed. I don't want to turn this into a major project as I plan on switching to LPG this year or next.

 

[nfg2u]

I will get you some photos, but it will be next week before I can get to the boat. I did a lot of research and learned a bit about valves before I got mine done. It wasn't as bad as I though it would be and turned out cheaper and I feel like a safer solution than LPG. If your cruising and not in the states then LPG is the way to go. I will send some pics Monday or Tuesday. The two regulators are what you would change. The connection fitting to the tank should be ok.

From the picture it looks like your discharge line is connected to the low pressure supply line past the low pressure regulator. Its a safety overpressure relief. Mine goes out through a through hull above the waterline.

 

[Marrigoround]

Here's one for $85. Do I need to buy two of these?

https://www.ebay.com/i/192642341452?chn=ps