David,
I had restarted a thread a few months ago asking for advice on the same issue ( https://groups.google.com/d/msg/INA-Nonsuch-Discussion-Group/4lRftLcjmsg/9ii80uXRAQAJ ). My 30U #516 has (had) a Wolter unit with a water leak and it was clear that the unit had been repaired numerous times before. Many members offered very helpful advice including Joe who suggested the engine system. I spent a week weighing the pros and cons of each option and ended up deciding to replace the unit with a new Excel system. For me the on-demand propane system is a better fit for how we use our boat. At the time Excel was out of stock of their “Tankless On-Demand Gas Water Heater VENTFREE – Propane (LPG) – Low Water Pressure Startup” unit for $220 but they sent me an email when it was available and I received it a few days after ordering. Their customer service is excellent.
I installed it last week and it was an easy job taking me only a few hours after I had the correct water line fittings purchase at a local hardware. The mounting hole pattern on the Wolter did not line up with the Excel like I’ve read about the Paloma’s but the old holes will be easy enough to plug and refinish. The new unit physically fit perfectly and although “vent-free” I was able to use the old exhaust hood to connect the output of the Excel to the charlie noble. I would be happy to discuss over the phone if you want a more detail.
Now my two cents worth on safety which is the primary concern for running a “vent-free” system in the boat.
I would never use this system without a working marine grade propane detection system. A friend of mine lost his life recently in a propane accident on his boat while using the stove/oven and since that time everyone in our club has installed a system in their boat.
I would never use this system without a working marine grade carbon monoxide detection system. Even though the unit is “vent-free” it isn’t a risk I am willing to take. I also want to fall asleep without worrying about waking up in the morning.
I would suggest connecting the exhaust on the Excel to the old vent in the cabin top. Any exhaust byproducts you can get out of the inside of the boat only makes it safer even though the manufacturer states that is is fine without that.
My boat is equipped with 2 separate propane hoses running from the cockpit propane locker to each appliance (stove & heater). This is the current ABYC standard and if your boat has a tee fitting outside of the locker (inside the boat) I feel strongly that you should change that. This was the cause of my friends accident when a leak developed between the tank and the stove.
The solenoid and tank valve should be closed after each use of either appliance and only reopened when ready to cook or heat water.
The system should be leak tested regularly to make sure no leak has developed in the line(s) running through the inside of the cabin. This is as simple as closing the solenoid, shutting the tank valve, and noting the pressure on the gauge which is downstream from these. Leave it for an hour or so and check the gauge again to see if it has gone down at all. A leak free system will still have very close to the same pressure as when it was closed off. My system loses a few pounds of pressure after several hours. In a hose with such small capacity this indicates a very small loss of gas. A leak where the system pressure goes down quickly tells you that propane can enter the cabin whenever you are using one of the appliances.
It’s my feeling that with the proper detection systems installed, up-to-date gas lines, and regularly checking the entire system for leaks that you have a very remote chance of having an accident. This, plus the way we use the boat, and cost were the reasons I ended up replacing the old on-demand system with a new Excel.
Greg Doyal
NS30U #516 Challenge
Grosse Pointe, MI
