Propane leak

[Syversens]

Hey all,

so last weekend our on and off propane leak turned into a full on tank drain with very reduced cooking before tank was empty and air not safe/breathable. I didn't do too much fault checking but did a few things:

use a sponge wet with soapy water (no spray bottle on hand) on fittings around regulator, hose to tank and fittings between solenoid and regulator, no obvious leaks. I did notice that the solenoid gave off steam when hit with soapy water. I thought this was strange but did some search this afternoon finding its normal that it gets hot.

So I'm thinking of replacing my entire gas fittings back there, boat is a 99 and except for the hose to tank that I replaced earlier its all original. But before I do that, anyone have any advice on what else to check? gas leak certainly put a damper so I'm leaning towards full replacement to bring back confidence.

Cheers!

 

[centerline]

have you figured out if it is leaking before the solenoid or after?

the solenoid should be within a foot or two of the tank valve, so it shouldnt take much effort to find the leak...

dont overlook a leaking regulator. ive seen a few times where the diaphragm was ruptured and let gas out into the surrounding atmosphere...

 

[Ron20324]

Get an adaptor to connect the small propane bottles to your gas line. Not for full-time use, but could save the steaks from being served raw.

 

[Gunni]

You need to find the leak before using the propane system again. Once propane gets loose inside the boat you have a very dangerous situation. A soapy sponge is not a suitable leak detection device. If the leak is not inside the propane locker, get some pro help.

 

[Syversens]

the leak is definitely inside the propane locker and I'll try to use a different way to apply soapy water, or is there a better way to detect leak?

We shut off the tanks and that stops it (not surprised) so the leak is not the tank. It might be from there on though. I was thinking maybe turn on propane, pressurize and turn off at tank, leaving solenoid on and one time doing the same with it off. that should narrow it down to before/after solenoid. the curious thing is that it almost seems temperature dependent, so in the morning when cold it leaks and when it warms up it stops.

We've stopped using it and at this point considering either whole gas regulator/solenoid replacement or pieces. Given it only leaks certain times I'm leaning towards full.

 

[Gunni]

Yeah soapy water in a sprayer works. Open the tank valve and the gauge should show about 100psi., shut it off and and it should stay at 100 psi if the system is leak-tight. Then you are just checking all fittings for leaks.

 

[centerline]

the leak is definitely inside the propane locker and I'll try to use a different way to apply soapy water, or is there a better way to detect leak?


We've stopped using it and at this point considering either whole gas regulator/solenoid replacement or pieces. Given it only leaks certain times I'm leaning towards full.

there is a soap solution designed for use in testing for gas leaks, or you can add glycerin to common dish soap to make it have a tougher and longer lasting "skin" so the bubbles will be more robust and prominent.
a lot of times the dishsoap/water will not allow the bubbles to form and you can actually miss a leak... it may work in a pinch (not always), but if you have a severe leak, the gas can leak so fast that it wont allow a bubble to form, or the leak can be so small that the bubble can dry out and pop before it shows the leak..
kids bubble blowing solution works great and is almost identical to the commercial leak detecting soap.

but a leaking regulator diaphragm is hard to detect with any soap solution because the escape/equalization holes in the regulator are too big to allow the soap solution to bridge them, or there are a couple holes and the solution wont bridge then at the same time...

the solenoid valve can leak at either the inlet or the outlet, but it leaking anywhere else is not impossible, but is next to impossible unless there is corrosion in it... its a lifetime sealed and non serviceable valve that is controlled externally by a magnetic field...

I would suggest you scrutinize the regulator as the diaphragm can leak at times and not at other times, depending on where its at in its travel limits of being balanced between the gas and spring pressures, and how stiff the rubber may be when its cold vs when its warm.

 

[Syversens]

Problem solved, removed whole assembly and took it to a RV place. They tested and found leak. Put new regulator on ($7) and tested again, no leak. Finally got to remove the propane bin from port side on our 361, always thought it was complicated and though not easiest thing, certainly not bad. The solenoid is getting hot and the RV people said that was totally AOK and said the one I had was not just good functioning now but a very good solenoid. yay

 

[Tally Ho]

?..and air not safe/breathable...Cheers!

if the leak was in the propane locker, where were you smelling the propane? I assume you meant in the cabin...so I would be worried that your locker is not vented outside properly.

Glad to hear you got it solved though!

Greg

 

[Syversens]

Actually it was all in the locker, not sure what the drain capacity is but I suspect not enough to deal with a proper leak. No gas made it into cabin so it's sealed well, something I learned taking it apart to take off regulator.

I checked it again today and after 24 hours, solenoid and gas both off, the pressure was down 7psi from about 150 to 143... I'm thinking that could either be temperature or something, how long should one expect to keep pressure with everything off? I read somewhere that if pressure stays after 20 minutes its ok so I'm thinking 24 hours is good.

 

[Davidasailor26]

The pressure of the tank itself is dependent on temperature only, provided you have any liquid propane left in it. The liquid will evaporate and expand into a gas to maintain equilibrium with its vapor pressure.

 

[Gunni]

Isn't the vapor pressure for propane somewhere around 110 psi?

 

[Gunni]

So I checked - LPG bottles can keep a vapor pressure between and 100 and 200 psi, temperature dependent. It being warm 150psi seems acceptable. And yes, your pressure gauge is your crude leak detector. Solenoid off, bottle valve off the pressure should hold static for the duration of a temperature-steady leak test.

 

[Syversens]

Sounds good, I think I'm sorted then, now on to my head backflow issue... think I prefer working with the gas over head system any day.

 

[James Simmonds]

Head back flow is easy -you need a new Joker valve. A cheap and easy fix.

 

[Newport Bob]

Right, but replacing the joker every 6 months is getting sh***y for me. Never had this problem on the last boat where the designer was smart enough to flush down hill to the holding tank instead of UP three feet plus.
2004 bene 373 two berth

 

[Syversens]

Its a bit more than that unfortunately. We have a electro scan (LOVE IT) and last trip our joker valve failed but also pointed out a weakness with my rookie installation of not having a vented loop between toilet and tank. Tank is above waterline but toilet is not, so when joker valve failed it all came back. Putting in a vented loop this time, and recognizing I'm an idiot for not doing it the first time.

The joker valve actually lasted 5 years on our current toilet, the 2 years before that we had a Groco toilet and did it once or twice. We have Raritan Elegance now and the combination has worked out great.

Have to learn some way and this was a good lesson for me.