Propane instant water heater

remetau · Posted: Fri Feb 19, 2010 7:40 am Post subject: Propane instant water heater

We have decided to go with a ventless propane instant water heater and get rid of our 6 gallon electric water heater.

Has anybody else on here gone this route?

mimoza · Posted: Sun Feb 21, 2010 12:32 pm Post subject:

I'm sure you've thought about it for a reasonable length of time, but even with the addition of the instant propane heater, I would hesitate to take out the electric heater for two reasons:
1) You get free hot water heated from the engine. Even when it isn't heated to a good enough temperature, it will make it easier for your propane heater to do its job.
2) When available, getting electricity from the power hookup is easier than going out to buy propane.
These two things will save you money, hassle, and propane, which may mean that you are still able to cook when you might otherwise have exhausted your propane supply.

I like to have alternative systems on my boat, even if they aren't perfect.

Great_Aardvark · Crew Joined: 08 May 2009 Posts: 148

I am assuming the reason for getting rid of your hot water tank is save space. The tankless water will most likely be the same size as your current water tank. If it is to have hot water without either keeping the power on in the heater or waiting while the water heats then a tankless is a good answer although propane is perhaps not the best choice. This is due to the limited supply of propane the boats are designed to carry. Another alternative is diesel. The amount of fuel is much greater and also easier to get (just drive up to the pump).

If waiting is not an issue then there is another choice. I am installing a Wabasco heater that not only will heat the cabin but I have it setup to also heat the water. Another option I have is I have a heat exchanger that uses the engine coolant to also run through the cabin heater (which will also heat the water) so I only use diesel fuel for the engine that moves the boat but heats the boat and the water.

So when at the dock I heat water with electricity, at anchor heat the water using the Wabasco (it has a summer by pass so I don't heat the cabin if not needed), or when motoring the engine heats the water (and if needed the cabin).

I also have installed a 12 gallon water heater which means I once heated I have plenty of water.

Tony

mimoza · Posted: Wed Feb 24, 2010 4:28 am Post subject:

Webasto heaters are a good option, especially in cooler climes, but propane = unlimited hotwater (OK, limited by your water and propane supplies.)

The Webasto is more versatile and uses a resource which you will usually have more of - Just make sure the fuel pickup doesn't go all the way to the bottom of the tank. You want that built-in reserve for the engine only.

Great_Aardvark · Crew Joined: 08 May 2009 Posts: 148

Don and Diane,
If you should decide to go with the Wabasco I should have mine installed soon (as soon as the weather goes from below freezing to summer weather at the rate I am going) and can send you pictures and suggestions on how to install. I have the Wabasco 90 S which delivers 31,000 BTU but since you are in the warmer climate you might get by with the TSL 17 17,200 BTU which is much smaller and easier to find a spot for, I had one reply from someone who mounted their 17 in the lazzeret, mine is going in the cockpit locker. Capt Bri is right about the fuel pickup. On my last boat I went down only about 3/4 of the way leaving 1/4 of fuel available. This boat I will leave more. Since I am also replacing the water tank I can send info on that such as the model and make I bought and installation. I wanted a tank that held at least 12 gallons and was well insulated so it would keep the water hot for a couple of days.
Tony

riggsy · Landlubber Joined: 21 Jan 2010 Posts: 13

We are also considering a Webasto and would love to see pictures of your installation,

Ziggy

HC 33 Hull #92
svDionis

Great_Aardvark · Crew Joined: 08 May 2009 Posts: 148

You bet. I am just finishing the new hot water heater installation and will send some pictures of the heat exchanger that allow you to heat the cabin using the engine heat instead of running the engine and the Wabasco. It uses the Wabasco's pump but not the boiler. Also the throttle that you need on the water heater. I will send these by Monday. Next I will send the radiator installations and how I ran the hoses. I hope to have the heater installed by the end of next week.

Tony

remetau · Posted: Mon Mar 01, 2010 11:37 am Post subject:

Capt Bri and Tony,

Thanks for the info. I think we'll stick with the idea of using an instant water heater. I don't want to use space to store hot water. We decide to remove our existing water heater for space in our equipment locker. We'll be putting four new Trojan batteries in its place. We went back and forth on this decision since we do get water heating from the engine and from 120v on the dock, but we don't spend much time at a dock and our need for heated water diminishes greatly in the summer time.

Our tiny propane locker only allows the use of 2 small 5 lb tanks so we also decide to install a new propane tank and system in the deck box. This tank will be used for the water heater and the existing propane cabin heater.

Great_Aardvark · Crew Joined: 08 May 2009 Posts: 148

What size batteries and how many are you going to use? Will these be under the quarter berth?

Tony

clonjers · Posted: Tue Mar 02, 2010 9:25 am Post subject:

I'm sure I am dated, but many years ago I looked into propane heaters they were not recommended, because as the boat rock/rolls the flame will have issues becuase it still burns up, and the elemnt is not in line, amybe old news..