Propane leak or no big deal?

[DestinySoyQuick]

I’ve been a boat owner since June 9, 2023, and have been using the propane system for the stove / oven with no issues until the other night. I left the master switch on for the propane system (red switch pictured above refrigerator switch on electrical panel.) This switch enables the propane system which includes a Trident Marine LP Gas Control & Detection System box in the galley about 3-4 feet aft of the stove. I had this switched to “off”…

Boat was pretty closed up for the night and in the middle of the night I heard the alarm go off on that little LP Gas Control & Detection System box. I did not smell any propane but it could also have picked up on very small amounts. I switched off the system with the red master switch and opened some portholes.

Side note… propane system still seems to work fine.

However, next morning I went aft to the propane cylinder storage area (photo attached) and when I opened it, could smell propane coming from that compartment.

I don’t know much about LP systems and am seeking advice. Is system operating normally? I remember as a kid there was a big propane tank outside of my family’s home and sometimes I could smell the propane coming from it. I think it maybe had some kind of mechanism to let some out at times due to pressure? Or… another possibility is that everywhere I go, potentially dangerous propane leaks are sure to follow?

In all seriousness, any tips or knowledge about this system and equipment that you can see? How do I diagnose a leak? Soapy water? Thanks ahead of time and I really appreciate any advice. Seattle area, 1982 Cascade 36. Hep me fix in person and let’s go sailing? Or post comments please ⛵️⛵️⛵️ God Bless

- Sanna

[boatpoker]

You have pressure gauges in the propane locker. Did the pressure drop and if so how much and over what time period ?

[GreenWave]

First thing is to checks all fittings for leaks. Start with all switches off, then enabled in various combos.

[Yojimbo]

Not sure how much trouble shooting you've done so far but the first step i'd take is to open/flood the system with propane then shut off the cylinders and watch the gauges. If one of them reads cylinder pressure and the other line pressure [usually the case] watch to see which drops pressure. If the cylinder holds and the line drops you have a starting point for tracking the leak. I've not followed this procedure with propane but several other gases- nitrogen/argon/acetylene/02. After determining the leak is in the line somewhere follow it down and soap test every fitting and connection. Rule them out and proceed to components, ie. valves/actuators/solenoids. These would be a good first set of steps but are sure to be a lot more of a PITA than described here.

Maybe before all that- if the smell is in the propane locker- could be the place to look/start. Try closing the cylinder, detaching the line and reattaching. I've noticed on the propane weed burner those cylinder valves get cranky with age and sometimes just taking something apart and reassembling does the trick. Good luck.

[Jammer]

There shouldn't be odor near the tanks.


Your best bet is to shut off both valves and the switch, then slowly open each of the tank valves all the way and shut it. Note the pressure on the gauges (should be the same or nearly so). Come back an hour later, if the gauges have moved, you have a leak in the connection to one of the tanks, or the regulator, or the solenoid.


Then rerun the test with the switch turned on, to see if you have a leak between the solenoid and the range.

[HopCar]

Pick up a hand held propane leak detector. They aren’t expensive.

[wholybee]

You should pressure test the system regularly. Turn the system on. Open the valves on the tank, then close them. Leak the system on. Watch the gauges for 10-30 minutes. They should not move. If they do, there is a leak somewhere.

Regulators do fail, and when they do will leak through a small vent hole. I have had bad luck with trident regulators. But the leak could be anywhere.

Don't be shy about calling a pro if you need to. Propane leaks are dangerous.

[HeywoodJ]

The regulator in the locker (in your photos the silver block with the black knob that is in between the two gauges) has a vent hole to release over-pressure. This can very rarely vent under normal conditions, generally when temperature increases, line is closed, and the temperature swing increase the pressure. Not normally a morning/night thing, usually an afternoon/evening occurrence. This can happen, but should be pretty rare. If you smelled propane in the locker once on a warm afternoon I might be less concerned. More than once, or not after a big temperature increase could indicate the vent is starting to leak. This is a pretty common/typical thing and the easiest solution is to replace the regulator.

My only question would be why a possible leak in the propane locker would set of a detector in the hull. The whole point of a separate, drained-overboard propane locker is to keep the leaked propane out of the boat. The detector going off is either an indication of a leak in the plumbing, or, since you smelled propane in the locker, and indication that the locker is not completely isolated from the cabin.

[Chotu]

You should do the leak down test with the gauges.

You should also remember that hydrogen from charging batteries will set off a propane detector.