I decided after 37 years to replace the propane supply hoses, pressure gauge, regulator, solenoid, and propane sniffer on my NS 30C. My question is about checking for leaks. The system passed the soapy water test. Notes in Boat US information about this task state that the system must hold pressure for a minimum of 3 minutes. The original Seaward stove info states that the system must hold pressure for 15 minutes. I suppose that if the pressure begins to drop ever so slightly after 3 min or 15 min, whichever I choose, there is no need for concern. This puzzles me because the pressure does, in fact, slowly drop to zero after several hours. This tells me that propane is escaping into the bilge. Doesn’t sound safe to me!! I will appreciate some advice. Also I have noticed that the solenoid does heat up a bit (feels hot to the touch) when turned on to allow propane to pass through. Is this normal?
Thank you!
Bob McPeek
Pau Hana, NS30C
The solenoid switch consumes the most power on our boat, fortunately never open for very long. As for the leak down. We open the tank valve then the solenoid, use the appliance, shut the tank, and let for example the stove burn out… the turn the solenoid off.
Several hours, being less than 3 may be a concern. I have a propane expert coming by tomorrow, I will ask him…
T
We follow the same practice as Thor. We also have a length of red wool tied around the propane line in the propane locker. When we open the valve on the tank the wool is draped over the edge of the locker. When the valve is turned off we tuck the wool back in the locker. This give us a visual reminder to shut the tank off. The valve on the tank is only open while we are using an appliance and we burn off the propane in the line when we are done.
Leak down tests show it takes several hours for the pressure to fully drop in the lines. My guess is that the most likely point for lose of pressure is the galley stove. Propane is explosive when the propane to air mixture is between 2% and 10%. https://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html
Mark Powers
La Reina 26C
Vancouver, B.C.
The installer came today and here is the info.
The soap test, the 3 minute rule, because it can take time for bubbles to form.
The system should hold pressure and he would not accept the kind of loss you are experiencing.
He thinks there may be a leak at the on off controls of an appliance . His suggestion is to cap the lines, then check. This eliminates any defects in the line and attached terminal fittings. Then connect one appliance at a time and wait for the culprit to appear
Thor
For 20+ years I followed the same procedure as you. The Paloma heater died and I purchased an Excel which does not have a pilot. I decided it was a good time to replace all the hoses, wiring, regulator, solenoid, sniffer, pressure gauge, etc. I hired a propane guy who was recommended to me, but he was a real disaster. I haven’t been able to find anyone who understands the propane system on a boat. Of course, propane collecting in the bilge is the problem.
I have two propane hoses from the locker, one for the water heater and one for the stove. Each has a shutoff valve in the propane locker. I connected the propane tank to this plumbing with both valves shut off in the locker and the solenoid on. I used the commercial leak test solution that I purchased. No leaks.
Pressure gauge read 140 lbs. It held 140 lbs for 10 minutes.
After 10 more minutes it read 135lbs. and held at 135 for a total of 40 min
After 40 minutes it slowly began to drop tp 130 lbs.
After 55 min it dropped to 120 lbs.
Atfter 60 minutes it had dropped to 125 lbs.
So, it lost 15 lbs of pressure in 60 minutes
According to Thor’s installer, at the same ambient temperature there must be no pressure loss for hours, days, weeks…
Connecting the two hoses is my next step. It seems to me that with a water heater that does not have a pilot this hose must experience no loss in pressure over time. I will always shut off the propane tank when the water heater and/or stove are not in use. When I return to the boat after leaving it for an extended time, the water heater should just fire up right after I turn on the propane tank and the hot water faucet.
I think I understand. Is my explanation and conclusion above correct?
Thanks,
Bob McPeek,NS30C, Pau Hana
San Francisco.
Makes sense. Plug the lines at the terminal end in the boat with a cap. If it leaks plug it at the point where the lines connect to the devices in the locker.
My installer mentioned that regulators can sometimes leak, so pour some dish soap around and over the regulator may be a good first step before starting on the lines. IMHO it should not be dropping in this manner.
T
I’m not a gas fitter. This is just my observation.
The pressure gauge at 110 psi is between the tank and the regulator. After the regulator the propane pressure should be very low. A very tiny leak is difficult to find at this pressure.
With the appliance off, solenoid off(after the gauge) and tank valve off the 100 to 120 psi at the tank in summer will drop 20 to 30psi by breakfast. How fast seems to depend on change in ambient temperatures so maybe this drop is because the tank is colder in the morning. I have never seen 140psi but maybe it’s hotter in San Francisco as that is propane vapor pressure at 85 deg F. At our more usual 70 deg F propane vapor pressure is 110psi.
However, after a week the gauge always reads 0.
I’ve been told that the rubber hoses leak propane very slowly. I could not find a leak with soapy water. I find this leaking hard to believe but that appears to be what’s happening. It’s disturbing because if it is leaking where does it go? Propane is 50% heavier than air. If the gauge reads 0 the solenoid valve must also be leaking. At 0.5psi there isn’t much gas in the 12 feet of hose so I’m not worried.
After a week, the hose seems to be empty of gas or has gas in it that is below the required concentration to ignite at the stove so the line has to be bled for 10 to 15 seconds. If the stove is used once a day or even after two days, no bleeding required.
Where this was a pain was the Paloma. I had to hold the pilot button down for ages before it would purge the hose and light after leaving the boat for a week. My insurance company made me remove the Paloma. Solved that problem.
Other boats with propane stoves have the same issue so I thought this was normal.
I also try to remember to close the tank valve whenever I’m not using the stove.
Leaving the solenoid on, draws 1 amp, and it can get nice and warm.
I definitely need a new sniffer after 39 years.
Tom
26C #28
Penetanguishene
I get 100 psi on a full tank like Tom. After the tank pressure s really does not drop until nearly empty. But when it drops iit is a sigh we are close to empty. Ambient temps in the mid 70’s F We never leave the tank open for very long so I have no idea what the leak down may be.
Thor, Mark and Tom,
I thank all of you for your thoughts and suggestions. Have any of you installed an automatic tankless water heater such as the Excel? If yes, does the gas line need to be bled or purged whenever the water heater has not been used for a few days due to the “automatic” loss of pressure in the gas line, or do you just turn on the hot water faucet and let the battery powered lighter click away for a minute or two? ?
Bob
Bob,
La Reina came to me with a Wolter on demand propane fired water heater. I replaced it with an Excel heater. I do not have to bleed the line to use the heater. I turn on the water and can hear the igniter click briefly and then hear the propane ignite. It fires up much quicker than the stove top. Typically it fires up within 5 to 10 seconds. Usually in the 5 second range even after the propane and heater have not been used for a few weeks.
Mark
I plan to install a Excel in the spring… took out the old one P a few years ago.
Hi Mark,
This is very helpful. Do you turn off the propane when you leave the boat?
Bob
Even though Katmando has a propane detector I make it a point to turn off the propane at source when I am not using it.
Brian McCuaig. NS30u
Whitby, Ontario
“Having a yacht is reason for being more cheerful than most."
Just a comment about the Excel propane heater: early last season, Leda’s would not light. Perusing the instruction manual (or maybe this forum, I can’t remember which), I read that low water pressure may be a cause for lack of ignition. One replacement pump impeller later, I was back in business.
Julian Smith
Leda
N26C
Shelburne, VT
Just a comment about the Excel propane heater: early last season, Leda’s would not light. Perusing the instruction manual (or maybe this forum, I can’t remember which), I read that low water pressure may be a cause for lack of ignition. One replacement pump impeller later, I was back in business.
Julian Smith
Leda
N26C
Shelburne, VT
Thank you, Julian. This is very helpful information, and possibly will save me a lot of time someday.
Bob McPeek
Pau Hana
NS30C
San Francisco
Hi Brian,
Thanks. I do the same. Does your on demand water heater, perhaps an Excel, light right up without having to bleed the line?
Bob McPeek
Pau Hana
NS30C
San Francisco
I don’t know how old Julian’s Excel water heater is, but a few years ago Excel came out with a new model that is lights even with very low water pressure. I had been having some issues so I upgraded to the new model and have had zero problems since then.
Jim Cosgrove
FATE 30U #343
Galesville, MD
Yes except if the boat hasn’t been used for a few weeks. Then I just light the stove for a few minutes.
Cheers
Brian McCuaig. NS30u
Whitby, Ontario
“Having a yacht is reason for being more cheerful than most."
We turn the propane off at the tank after I finish with the appliance, stove or water heater. There is a plastic note by the stove to remind me. If we are leaving the boat or going for a sail we burn off the propane in the line.
MArk