Cabin Heater Tank

[Roger Long]

I discovered that my main fuel tank is just a few inches too low for gravity feed to the Newport diesel cabin heater I'm installing. I don't want to be dependent on a pump or have to listen to it clicking so I'm having a small gravity tank made.

I have a fuel polishing system on my boat that is circulating fuel whenever the engine is running.

http://www.rogerlongboats.com/FOpolishing.htm

So, how cool is this?

http://www.rogerlongboats.com/images/HtankPiping.gif

The 1.5 gallon tank is simply inserted in the line that runs from the polishing system back to the main fuel tank. It thus fills automatically with just filtered fuel when ever the engine is running and this fuel is constantly renewed. If I run the stove for a long time and need to refill the tank, I just turn on the polishing pump for a few minutes. No lugging Jerry jugs around, no worry about over pumping and spouting fuel out the vent.

Although the tank is unlikely to overfill, the vent does need to have a check valve on it just in case. The Forespar replacement cap and duckbill valve for their anti-siphon loops can be screwed onto a 1/4" NPT x 1/4" tube compression fitting like the parts were made for each other, which, maybe they were.

http://www.rogerlongboats.com/images/Vacbreak.jpg

The length of copper tube will stick up without support to the highest point I can reach with it up in the cockpit coaming. The air bubble in the tube and the top of the tank should prevent oil from ever reaching the little joker valve.

[Pacific Woody]

Nice. I just hauled an old kerosene heater out of mine and swapped in a diesel (the kerosene was loud and so old that the flame was open to the main cabin.....greater fire AND carbon monoxide risks).

I like your system and might put a similar one in if the gravity fed system in ours isn't working as well as it might.

thanks

[Lew Barrett]

Well I think it's a great idea Roger, but (in a manner of speaking ) you are still left relying on a pump, even if it doesn't run when the heater does. However should the pump fail, your toes will go cold eventually! Not that it will....and of course you have dodged the annoyance of hearing the pump click at anchor. But if I read you correctly, you still need a pump:D

[Roger Long]

However should the pump fail, your toes will go cold eventually!

I already have the pump in the system. It's just a matter of cutting the discharge line and hooking it up to the tank.

Yes, my toes will get a bit cold if the pump dies but it will be from going out in the cockpit, taking the hose off the tank manifold in the cockpit seat locker, sticking a funnel in it, and refilling the heater tank. After that, I'll go back and stick my cold toes in front of the heater. Not much worse than the usual gravity set up where you have to fill the tank by hand each time.

I also have a little portable electric fuel pump that I use for transferring fuel from Jerry cans to the main tank. I can stick the hose from that into my main tank or even just plug that pump into the hoses for the polishing system.

The polishing pump BTW, is the same one most vessels are reliant on to keep their engines running. They are pretty reliable.

I'm covered:)

[SV Papillon]

It's actually the ideal daytank setup, in your case you are using it for your heater. Normally the engine etc daytank is always full of clean fuel that is constantly turned over in some capacity. Any issues with you main storage and you have a clean reserve. One important item is your vent, ideally it should vent into a receptical with a float that will break a holding circut on the pump. Or you could install your overflow to the main tank at 3/4 of the way up then put a tee in the heater port and the vent port with a murphy float switch plumbed just over your overflow port. It sounds much more complicated than it is. Anytime you are ciculating fuel that is vented above deck there is the potential for a spill this will greatly reduce it.

Jake

[Roger Long]

Anytime you are ciculating fuel that is vented above deck there is the potential for a spill this will greatly reduce it.

The exit from this tank is actually a vent since it tee's into the fuel fill manifold which always has one valve open. If the main tank is 105% full, the heater tank won't vent which is what the 1/4" line with the anti siphon valve at the end is for. The vent is inside the boat up under the hollow cockpit coaming.

The two main fuel oil tanks on my boat also have their vents connected. Normally, combining vents is a no-no but I've had no problems and it insures that a distraction during fuel transfer will just circulate the fuel around and around instead of spouting it out the fuel fill or pressurizing the fill lines.

Here's my fuel system:

http://www.rogerlongboats.com/images/StriderFOschematic.gif

The heater day tank goes where the 3/8" is in the green line. One function of my fuel system is that, in the event of the main Racor filter loading up, I can turn one valve under the companionway (the purple one) and flow from the polishing system goes immediately to the engine. If the polishing system filter should then load up, a gallon of fuel will drain back by gravity from the heater tank with no further action on my part.

This system was a retro fit and the main tank very inaccessible so I had to do some other things that are no-no's such as teeing the polishing system into the main fuel supply line. It has worked perfectly for two seasons though.

More here:

http://www.rogerlongboats.com/StriderFuelSystem.htm

[willmarsh3]

I would build a simple gravity feed tank with a feed from the line that draws fuel from the tank for the engine. In this line I would put a valve to isolate it, then a pump to be run to fill the tank. Then use what ever filter the stove requires. Put a guage on the gravity tank to monitor how full it is.

Use a check valve in the top to expel air as you fill the tank so it doesn't force its way into the stove but don't rely on it to prevent a fuel spill.

During operation run the pump for a few minutes per day as needed to fill it. Otherwise enjoy the golden silence.

This way would minimize adding additional complexity to your system.

[Roger Long]

This way would minimize adding additional complexity to your system.

That's simpler? I'm not arguing with you but I like these design philosophy exchanges. Maybe that's why I'm a naval architect.

Let's break it down:


I would build a simple gravity feed tank

We're both doing that.


In this line I would put a valve to isolate it, then a pump to be run to fill the tank.

Let's see another pump, a switch, a fuse, a cable run, another valve. Pump: 60 bucks, switch: 8 bucks, .... I already have all that stuff installed and running whenever the engine is keeping my fuel clean. What's simple about adding and paying for all that?


Then use what ever filter the stove requires.

We're both doing that. I could probably get away without it due to my polishing system but it's good insurance and the filter has a nice shut off.


Put a guage on the gravity tank to monitor how full it is.

Now the tank has to be where you can see the gauge. Gravity tanks want to be fairly high. That greatly limits the location. Mine will be tucked away in an otherwise useless spot. Alternatively, a remote gauge can be used. Another set of wires, a place to mount the gauge. Is that simple?


Use a check valve in the top to expel air as you fill the tank so it doesn't force its way into the stove but don't rely on it to prevent a fuel spill.

If it will expel air, it will expel fuel oil. Forcing air into the stove lines will really make things troublesome. Operation of your suggested set up requires watching the gauge carefully as you pump. That's simple? I can leave my pump running all day long and all that will happen is that my fuel gets a little additional recirculating filtering. Any air in the tank is expelled into the main fuel tank. No fumes, no overflow risk. The vent in the top of my tank is a check valve the other way to let air IN so the tank will gravity feed.


During operation run the pump for a few minutes per day as needed to fill it. Otherwise enjoy the golden silence.

We're both doing that except that, if I have run my engine since using the heater, the heater tank will already be filled.

What could be simpler?

[wizbang 13]

dang. putting it down low was my advice. hope you don't regret it.

[Roger Long]

dang. putting it down low was my advice. hope you don't regret it.

It was excellent advice and almost everyone here and elsewhere agreed with you. Why would I regret it?

[willmarsh3]

I have given some thought to putting one of these stoves on my boat but haven't made a final decision so this is good to think about. I think I'm going to use a gravity fed day tank near the stove.

My thinking evolves as I write this so here goes.

It's true that my setup might have some more upfront costs e.g. pump + wiring + switch. But there's some savings from less fuel hose. Otherwise no argument there.

But I see some advantages:
1) Only one fuel line running forward as opposed to two.
2) No possible impact on the existing system e.g. due to longer lines.
3) Independence from the fuel polishing system. If you regularly polish the fuel then it should be quite adequate IMHO for the stove filter to handle.


A fill procedure with my setup would go like this.
1) Open the isolation valve near the diesel fill line.
2) Run the pump and observe the guage. When it nears full shut the pump off.
3) Close the isolation valve.

And it would operate independently of the fuel polishing setup.

Perhaps a slight modification that would save the cost of a new pump would be to tee off the line just after the output of the fuel polishing pump and use a mirror or have a crew member to watch the guage. The guage would be local to the day tank.

One question remains - how to get the fuel to go to the day tank instead of the fuel polishing filter. If the fuel polishing filter has high back pressure then the problem is solved. If not then either a three way valve is needed (less chance of operator error, IMHO) or a separate valve to the stove day tank and one to the fuel polish filter. I would pick the three way valve option hands down.

The only other issue is the air purge valve on top of the day tank. If a check valve is installed that lets air into the tank when the stove is operated, then there needs to be a way to let the air out when the tank is being filled. You or your crew member would open this valve during the filling operation then shut it. Then no leakage.

If instead, an air return line is installed leading back to the top of the diesel tank then that would obviate the need for this valve. And it would impose an automatic limit on the height of the fuel in the day tank so that would obviate the need for a guage. You could then also do away with the check valve to let air in but only if the air return line was sufficiently large and had no dips to collect fuel and block the flow of air. If you can't work the line to remove dips then the check valve becomes necessary. Also you may still want the guage to easily tell how much fuel is left in the day tank to know when to fill it. So my conclusion would be to use the check valve, air return line and local guage.

As for type of guage perhaps a sight glass would do. I've read where it's a bad idea to put a sight glass on a fuel tank because if there's a fire then it will break and let most of the fuel out to burn. But on a gravity feed tank then it would be releasing its fuel anyway so the issue is moot. Perhaps others can sound off on this.

So at this point what you have is a system for polishing fuel and alternatively by way of the three way valve after the fuel polishing pump a system for filling the day tank just for the cost of a fuel hose, a fuel return hose and a three way valve. And leaving the three way valve one way or the other unintentionally would have little consequence.

It appears that my proposed design is starting to look more like what you were thinking at the beginning. It may turn out that way.

[Roger Long]

But I see some advantages:
1) Only one fuel line running forward as opposed to two.

I only have one line going forward. The heater tank is back under the end of the quarter berth right next to where the polishing lines already run. I just cut the polishing system hose, connect the ends to the tank, and the rest is stuff I would be doing anyway. The fuel line for the stove then just runs forward. I wouldn't want the heater tank up forward. All that space is way too valuable for other things.


use a mirror or have a crew member to watch the guage. The guage would be local to the day tank.

Sound complicated to me; especially the crew part. I don't want to depend on having someone else on board just to fill my tank. I don't even want to worry about filling it. If I do have to fill mine due to a long period of heating without engine running, I just turn on the polishing pump and turn it off again whenever I think about it. It makes enough noise though that I'm not likely to forget it. Why have a gauge when it can just be automatically self regulating?


You or your crew member would open this valve during the filling operation then shut it.

Sounds like a recipe for a spill to me.



It appears that my proposed design is starting to look more like what you were thinking at the beginning. It may turn out that way.

Maybe that's why I'm in the design business:)

[willmarsh3]

Some good thoughts. I look forward to your website updates. I do appreciate the talents of designers. :)

As for me I don't have a fuel polishing system per se. I do have a Racor filter that goes to an electric lift pump on the engine. After the fuel injection pump the return line goes back to the one fuel tank. Most of the fuel gets returned so fuel polishing takes place but at a much lower rate than a dedicated system like you have. I put this in place August 2009. I'll give it a year's use and check how clean the fuel is.

I'll have to think some more about my installation. Some questions:

1) Do I put the day tank fill line in after the Racor or before? If before then the fuel isn't filtered. If after then I wonder if the pump is going to try to back suck the fuel from the engine and it have to be bled before operating. Perhaps a checkvalve in the fuel line could fix that. Or I'll leave the engine fuel system completely alone and use a separate feed.

2) I have three possible locations for the day tank.

a) In the port quarterberth - doesn't work because the gravity feed line must run somehow to the starboard side forward where the stove is.

b) Starboard side near the stove - easy to run the gravity line but the fuel fill line needs to run way aft.

c) Starboard side in a space aft of the galley. Then the tank can't be readily seen to see if there are problems.

[Roger Long]

Some good thoughts.

Here's another one:

By the time you have bought a pump to fill your heater tank and a filter for the heater fuel (it should have it's own), you'll have 80% of a polishing system. Why not pipe it up so as to have really clean fuel and the ability to bring an entire separate pump and filter combination on line with the turn of a single valve?

I am putting in a third, Dickenson supplied filter as well. That's primarily belt and suspenders and to cover me if I have any problems with the heater. Things like filters are always the first thing manufacturers ask about when things don't work right. Another reason is just in case any metal chips or debris get left in the heater tank during fabrication or any pipe thread dope falls in during hook up.

Small diesels don't return enough fuel to be very effective a recirculation filtering. If you should pick up a load of bad fuel, you have no way to clean it except to run a good deal of it through the engines and keep changing 20 buck filter elements. One episode of that would pay for my whole polishing system.

If I end up with bad fuel in my tank, I can run the polishing system as long as necessary, changing out filter elements that cost 1/10 as much, before starting the engine. A few days before launch in the spring, when the boat is on shore power on land, I run the polishing system for a few hours while I'm working on getting her ready. I then change the element and know I'm good to go for the season.

This kind of system won't clean a badly neglected tank that has a thick coat of biofilm on the walls but, once it's clean, it sure keeps it that way. After the second season I ran a stiff Pex tube hooked up to a filter all around the bottom of my tank, not a speck. I looked inside with an inspection mirror and could see the mill marks on the aluminum sides. Long legs under power in rough seas with a half full tank and the polishing system going also help as does Startron.

Did you read my polishing page?

http://www.rogerlongboats.com/FOpolishing.htm

[willmarsh3]

I studied the fuel polishing web page. It's definitely some good information that I need to heed in in preparation for eventual long term cruising.

After thinking some more I'm coming around to a design that incorporates a fuel polishing system. My latest (but probably not final) design tees off the fuel pick up, goes to a fuel polishing pump and then to a Shelco filter. Next in line is a gravity tank located aft with an outlet near the top to return to the fuel tank. A third outlet goes forward to the stove. The gravity feed tank otherwise has no openings.

I still need to figure out how I want to have it serve as an emergency supply in case the Racor filter loads up. Perhaps a line with a valve can be run from the output of the fuel polishing filter to be teed in after the Racor to serve in an emergency or long enough to change the Racor filter.

I definitely welcome any constructive feedback on this.

[Roger Long]

I still need to figure out how I want to have it serve as an emergency supply in case the Racor filter loads up.

Mine does that and I've just updated my system schematic to show the heater tank. Here's the whole system:

http://www.rogerlongboats.com/images/StriderFOsystem.gif

Once the red valve is opened after Racor load up, any interruption in the polishing system supply will cause fuel to automatically run back by gravity from the heater tank to the engine.

[willmarsh3]

Thanks for the good discussion. The rest of your website will keep me busy for a while.

[dskira]

Looks like a wood stove will be the way to go. Easy, warm, dry, and quite beautiful.
The smell to is nicer than diesel, the lightup is simpler.
Some like diesel I suppose:D
Cheers
Daniel

[Roger Long]

Looks like a wood stove will be the way to go.

Nice smell maybe but, have your thought about the ashes?

I'm also going to Newfoundland eventually. Easier to get diesel in out of the way places than wood suitable for burning in a small stove.