Heating and Cooking

[Hiracer]

BTY, I think you can take any standard diesel heater and pipe the air intake to the outside, thereby achieving the same effect. Some of the manufacturors address this. You end up with volumunous piping, which is what makes coaxial attractive.

My heater sits above a settee, and I have given thought to venting the air intake to the interior sole, to suck up the coldest air down there.

BTY, if you can position your heater directly on the sole, that can really help big time. I tried but would have had to remove part of a settee and didn't want to give up the storage. And other reasons relating to stack positioning too.

Heating is a real puzzle. Glad I'm done. I do recall that cutting a five inch diameter hole in my cabin top was an existential moment. Or momemtS. Steel doesn't cut all that fast.

[D_e_n_n_i_s]

John,

Not goofy at all !! I think being safe is always a wise choice and I certainly respect your actions. Just so there is no misunderstanding, I'm an official cold weather wuss too !!! Florida boy, after all. That's why I harp on the details of heat so much. Sorry if I go a bit overboard with it. I've never used the coaxial vent and after hearing your logical points on it am not so stoked about it now. It may be a wash between the cold air of the intake by itself cooling the cabin versus the loss of heat in the exhaust pipe with the coaxial pipe design (cold intake inside the hot exhaust pipe). I bet with two pipes, you could really insulate that cold intake pipe and save more heat loss !!

I'm still pretty adamant about the closed combustion with my past experience of getting fumes into the cabin. That still makes sense to me. Apparently though, it's tough to get a good balance of air to keep the flame going given the years of attempts by Dickinson to develop such a device. Dickinson even uses a damper on their other models, but I guess that still doesn't help enough.

Dang, it really still gets warm with the dorades and solar fans open??? I guess I underestimate the heat from a higher BTU diesel heater. I love the Taylor design, but it's just not big enough to get it warm enough for my tastes. I suppose not everyone likes it 80 degrees and dripping inside (To be honest, it is VERY undersized). I had some solar fans that died; replaced 'em and those died, then I replaced them with deck prisms, which I highly recommend. The long prism design is nice, but the brightest are the ones that look like an upside down orange juice squeezer ... Sorry, sidetracked ...

Wow - tall stack. I do have a straight, long run with my exhaust pipe and I understand that this is critical for diesel exhaust. It makes sense when you think of natural draft, after all. I haven't found a system that can run without being attended yet so perhaps since I'll always be awake, the critical nature of fumes isn't absolutely life threatening, but long term it just can't be good for ya.

Anyway, I love to hear your thoughts as I've learned a lot from the banter. There's too often an angle that has completely escaped me, which is why I like to try to be critical of the systems to find out what really makes sense. Coaxial flue sounded so good at first, but there's more to it than appears at first glance. Thanks for continuing to share !!

[D_e_n_n_i_s]

Missed your last post before I replied - Great idea about mounting the diesel heater on the cabin sole as the cold air is there and heat rises so double whammy. The Dickinson models I was looking at (all but the Newport) mount that way, I think.

If Dickinson can't get the airflow right for the flame, then I'm hesitant to try my hand at it. I may engineer networks and software, but fire gives me pause ...

I hear ya on the cutout. I keep looking at my current vent pipe from inside the cabin each night and then think of cutting a larger hole or another one and ... yeah, it does really start to hit ya ... I can't imagine how agonizing it must be with a slow cut ...

[D_e_n_n_i_s]

I just got another reply from Scanmarine:
Doug McElroy added commentary to my questions (He replied in red, but I'm breaking out the reply in a seperate paragraph):

Thanks for the terrific, detailed response !! I'm learning that coaxial intake/exhaust isn't necessarily the way to go as two separate vent pipes (one for intake and one for exhaust) prevent the hot exhaust from being cooled down by the cool intake air and may be a better option.

Reply:
No. The preheated inbound air is a benefit to overall efficiency and when wind blows against the hull fitting, it blows both into the inlet and the outlet, meaning the flow is balanced and the combustion process can be allowed to run at a lower level without risking the burn being compromised. The 40D has to have a higher “low” setting, since it does not use coaxial exhaust/combustion air flow.
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I'm trying to better understand the design, especially as I am looking to buy both a higher BTU heater to replace my Taylor 079D diesel heater and a stove/oven combo to replace my CNG system and am looking at your 87D Stove/Oven combo and will look over the heaters you have. I understand the argument of having fresh air get into the cabin, but I can always manage that by opening hatches (not necessarily the better solution). What I need to better understand and my concern is if fresh air can get into the combustion chamber (combustion intake) AND into the cabin, then how can you absolutely guarantee that NO fumes (however small an amount it may be) cannot back-flow from the combustion chamber into the cabin? It seems there would be an open path from the combustion chamber back-flowing into the intake vent and from there into the cabin.

Reply:
Dennis – the combustion air on a 40D, or any of the stoves or ovens is FORCED into the combustion chamber by a dedicated electric blower (we call it the C fan). The C fan IS the inlet for combustion air. If the C fan were to stop, the combustion process stops and the unit shuts down. This is NOT passive combustion, so under all running conditions there is no way for combustion air to flow back into the cabin. Additionally, a 40D is normally mounted in an away space – an engine room, lazarette, etc., with its makeup air ducted to it from both outside and return air locations.
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Also, what kind of flex-pipe and angle concerns are there with venting a gimbaled stove/oven unit? I can't come straight up (bends are bad, I know) and would have to angle the vent going up. By the way, I need to exhaust vertically since going through a horizontal surface (side of the boat) would not be wise in a sailboat where water will cover the entire side of the boat at times.

Reply:
Any of our diesel stoves or the 40D can have up to 13’ of our normal exhaust pipe, more if a special system is built (larger bore, smooth wall sections). We do sailboats daily and most go out the side in the aft portion or out the transom.
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On the plus side, I have a perfectly straight exhaust on the Taylor heater and should be able to maintain this long, straight exhaust with one of your heaters.

Reply:
Not necessary.
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David, We need to have a telephone conversation. Please call when you have some time. Our toll free number is noted below.
Thanks!
Thanks,
Dennis
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Guess he didn't notice my name just below that last reply. I do like the idea of using a fan to keep positive pressure on the system. It seems that would, in fact, keep fumes from coming back into the cabin.

[D_e_n_n_i_s]

Doug from ScanMarine replied to an E-Mail I recently sent with more questions. I share it here in Q&A format in case it may be helpful ...

Question: It looks like the 40D is the most powerful heater you have. Let me confirm that it uses a coaxial vent and puts out more heat than your other heaters (14,000 BTU)?

Answer: The 40D is rated for a maximum 4kW or 14,000 btu. It is the highest output Wallas furnace. It does not use coaxial exhaust, but it uses the same coaxial style through hull fittings as the other furnaces, only fitted with a 602307 adapter, allowing connection of a single pipe to the duplex fitting.


Question: We can talk later about the cost to replace the 2467 Exhaust vent (Thru hull duplex) with the 3468 - Exhaust vent (duplex thru deck), but does the latter include a charlie noble or cowl vent cover (something to prevent the rain water from entering)?

Answer: 1. Both the 3468 and the 2460 are suitable for mounting on horizontal surfaces, each has a cover to keep rain out. 2. You should include a 602293 condensation drain at a low point between the furnace and the through deck fitting if you intend to go out the roof or deck. 3. The 5545 is not limited to use with any specific product. It is used to deflect wind away from side outlets on fast (>20 knot) boats. It has no real purpose on sailing vessels.


Question: If the 2460 Exhaust vent (closeable duplex) thru-deck is used to replace the 3468, would the 2460 let rain water in unless closed?
Does the 3468 prevent rain water from entering?

Answer: See above.


Question: To ask what may be an obvious question to you, does this unit use a glow plug or something similar to ignite the diesel and/or how is this unit fired off?

Answer: Yes, all Wallas products run an 8 – 10 amp glow plug for about 4 minutes during the start cycle only.

[D_e_n_n_i_s]

- Michelle with Dickinson Marine/ Sig Marine always provides a fast, thorough response to my questions. I've decided that I want to go with their Lofoten model, which will produce heat, heat water and even has a small cooking surface to act as a backup to the Origo 6000 with perhaps higher heat for some special dishes. I like the idea of the Wallas too ... maybe install it next year ... lol ...


Question: Lofoten has the cooking surface on it. What temperature does this surface get to, i.e. how does it compare with other dedicated cooking diesel stoves?

Answer:
The temperature of the cooktop would depend on how hot the heater is run and for how long.



Question:
It appears from the drawing that the draft assist fan is "under" the pot so that it forces air up from under (and through) the pot. This seems like it would help to provide positive air pressure in the cabin and help to deter down drafts, but it seems that down drafts still could force air from the fire into the cabin (thereby putting fumes in the cabin) with all of the air inlets in the pot itself. I guess the cap/charlie noble up top is the key to stopping down drafts in this system. Does it sound like I'm properly understanding how the system is set up in this regard?

Answer:
The draft assist fan is underneath the burner pot blowing air into the burner holes adding air to the "fuel to air mixture" inside the burner pot when artificial draft is needed to achieve clean combustion or for start up to help vaporize the fuel. It doesn't really help with the positive pressure or the draft going up the chimney. The positive pressure and the strong draft going up the chimney is more created from the fresh air vents you dedicate for your heater and the way the exhaust chimney is installed. Also, running your heater at a higher temperature will also fight against downdraft as the hotter the heater is burning, the stronger the draft will be going UP the chimney which makes it harder for the wind to come down the chimney. If the temperature gets too warm inside the cabin you could always open a window as it is better to burn the heater hotter then not hot enough. The weaker the fire inside the heater, the weaker the draft, making you more susceptible to downdraft. The cap really doesn't have much to do with downdraft either. The key is to have a strong draft going up the chimney and correct ventilation. (See pg. 5 of the Instruction Manual I sent you)



Question:
I appreciate learning that you have a safety high temperature shut off valve, which is something I would definitely want to buy. I have learned from my Taylor heater that gravity flow will drastically change the drip rate over a short period of time. I prefer gravity flow because it doesn't require power, but you don't get the consistent feed that you would with an electric pump. I'm just thinking through leaving the unit running while taking a shower, but clearly wouldn't use it for heating overnight while sleeping. I guess actual use and the level of fuel in the gravity feed tank will dictate these timeframes just like on my Taylor heater.

Answer:
Your Taylor heater may not have a float mechanism inside the valve. If you gravity feed a Dickinson heater, the drip rate will not change over time. If the gravity feed tank is mounted 12" above the valve the float equalizes the pressure so you drip rate stays the same.



Question:
From the manual it looks like the high temperature valve is a "fuse" that melts if the valve knob reaches 165 degrees. I'm hoping it's easy enough to change out the "fuse" as I've had my Taylor heater glowing red while trying to get enough heat out of it. Of course, it was just too small and given the BTU output of your units I don't see myself pushing them so hard. I guess practice is required like all things. I love the flame out valve. It sounds like with both low temp/high temp valves that there is a relative safety where one could walk away for 15 minutes or so. It just depends on how the gravity flow impacts the flame, I suppose.

Answer:
The high temp fuse in your valve should never melt. The bottom of the heater where the valve is located should never get hot enough for this fuse to melt. If it does, this means the fire is burning inside the burner pot INCORRECTLY. The fire should ALWAYS be burning outside the burner pot, above the top burner ring and the fuse should stay intact. If by accident the fuse melts it is very easy to reset.



Question:
In looking over the lighting instructions, it seems to indicate that you allow 2 tblsp of oil (diesel?) into the pot, turn this off, then light the oil (diesel fuel?) with paper (I use the long Bic lighters on my Taylor to great success-Using paper tends to have it float up out of the stack and land somewhere you don't want it topside), then replace the superheater ?? It says that this is priming fuel so perhaps I'm wrong in my assumption that you are putting 2 tblsp of diesel, but rather alcohol. I know that I have to prime my Taylor with alcohol, which is a small matter to me. Then, as the flame dies (just like my Taylor) you note to turn the oil metering valve to position one. My first question here is does the metering valve disperse alcohol in one position and diesel in another? I think I'm missing something here. Maybe your heaters don't require alcohol to heat the diesel for burning ??

The manual notes that you can leave the superheater in (my preference) and knock the paper down into the pot to light the oil (diesel?). I'm not sure of the access into the pot. For the Lofoten model, I guess you have access from the top (is this correct?). For the other models, it doesn't look like access is so easy. On the Taylor heater, you have a metal piece under the glass window with a single screw in it so the thing can be rotated open or closed (with a screwdriver when it's hot - lol). One of those long, Bic lighters is just small enough to insert into this hole at an angle to easily light alcohol in the bottom of the pot. I can't see how pot access works from any diagrams in the Lofoten manual and was hoping you could let me know how it works (pictures or description).

Answer:
Our heater's lighting procedure does not require alcohol. The safest way to light the heater is to fill the burner pot with a small pool of diesel. Light a piece of paper towel and throw it into the diesel. This can be done with the superheater left in, just make sure to use something to poke it down into the fuel. Then turn the fan on to help vaporize the diesel. Diesel is only flammable once it heats up and vaporizes. This is the priming stage. Once the fuel is burned off you can turn the valve on and the fan off or to low. Some use alcohols or different methods for start up but this is the safest way that we recommend. Generally, the small piece of burned paper towel sits in the bottom of the pot and works nicely as a wick for next time. I have never had it fly out of the chimney and land somewhere.

To access the burner of the Lofoten you would take off the cast iron lid and can access it through there. The other model heaters you can access the burner through the window but the Lofoten model I would say has the best access. See the attached picture for the access to the Bristol stove burner, very similar to the Lofoten heater.

Let me know if you have any other questions or if I need to clarify anything.
Kind Regards,

Michelle Parry
Dickinson Marine/ Sig Marine
Dickinson Manufacturing
407-204 Cayer St. Coquitlam, BC
V3K 5B1 Canada
Tel: 604-525-6444 Ex. 302
Fax: 604-525-6417
dmfgpurch@telus.net
www.dickinsonmarine.com
www.sigmarine.com

[D_e_n_n_i_s]

Well, I ordered the Origo 6000 from Defender last night. I'll wait to see what it comes with before ordering the accessories since the Defender reps and even the Origo rep that I communicated with weren't exactly sure (Manufacturers can offer different packages, I suppose). Things are still moving fast ... Whew !!!

[Brent Swain]

I'd much rather be on a secluded beach on the BC coast collecting firewood than working in a smoky shop, working to pay the oil companies for heat.

[D_e_n_n_i_s]

lol ... I hear ya on working to pay for the fuel !! I'm hoping to save up enough to cruise for a decade without slaving for the oil companies for the rest of my life We'll see ... I'll get back to you on that in 300 years

The secluded beaches aren't as problematic as those with inhabitants. Even islands with a small number of residents may be touchy about someone removing what they consider their property - You don't want to revive any long unused headhunter practices

There is a certain logic about using an apparently inexhaustable fuel source. Of course, keeping critters out of the boat is more of a challenge when bringing in firewood. It's not like you can keep wood on the porch and then bring it in only to put it on the fire... Plus, I need about 16K BTU without actually setting the boat on fire

[Brent Swain]

Thankfully I live in Canada, where everything below the high tide line is public access. No one owns it.
Next time I'm heading back to BC, I will gather my firewood and tie it in bundles . These I will hang over the side for a day to float all the scorpions etc off it , before laying it on deck to dry for we few days, then stowing it in the forepeak, and under the dinghy, for the trip home. That will give me enough heat for the last week of cold water, before reaching BC waters, and endless firewood.

[goboatingnow]

I think there is a general mixup between combustion air and heated air. Hence in Europe its illegal to fit ( for other then cooking) a combuston fired heater that either inputs combustion or exhausts such air into the cabin space.( this applies to gas powered fridges as well). where a system has a heat exchanger, then its a matter of choice as to whether the heating air is brought in from outside or inside. In my case with an Eberspacher the installations allways bring the heating air from inside as this improves the efficiency of the unit. ( it doesnt have to heat cold all the time).

[D_e_n_n_i_s]

I guess I don't understand the differences in terminology so let me list it out and perhaps you could clarify where I'm missing it.

- Intake (Fresh Air) can either come from within the cabin (Holes in the pot, etc.) or through an Intake pipe from outside the boat
- Intake goes into the "combustion chamber" either directly or vented through a fan to control the air flow
- Intake is mixed with fuel and a spark in the combustion chamber and fire happens
- The Exhaust Air (which is heated by the fire) exits through a pipe to the outside of the boat (Exhaust Air = Heated Air at this point)
- Heat from the fire pours into the cabin from the combustion chamber and from any Exhaust Vents that become hot

"Inputs combustion" - Do you mean that the exhaust air is recycled back into the combustion chamber. This sounds like pollution systems on cars.

"Exhausts such air into the cabin space" - Oh yeah, that's a big problem. Actually, my concern is when air can back up in the system and accidentally (certainly not by design) vent into the cabin (perhaps by a down draft, vent blockage, etc). Are you saying that a system, which could possibly have a down draft that causes combustion air to enter a cabin, is illegal or that one "designed" to do this is illegal? Almost any natural draft design heater that I've seen has the potential to back draft into the cabin.

[ConradG]

With the Espar (in the US and Canada but same company as Ebespacher) air heater there is an intake for the combustion process that ussualy comes from outside so that you don't send your warm cabin air out the chiminy (exhaust). Then there is the cabin air that is heated with an intake and warmed air outlet. Just a small hot air oil furnace like one would have in a house. They also make a boiler or "coolant heater" just like a boiler you would have in a house that you can use for radiators, hot water, radiant floor heat or water/air heatechangers. They are known in the trucking industry for keeping the engine (and cab) at temp overnight instead of idling. Also used for engine preheat in cold climates. They have a circulator pump and keep the coolant at 180F cycling on and off as needed just like a boiler in a house but smaller than a glovebox and rather efficient. Best thing about both is that they burn diesel which one ussually has plenty of and access to.

[D_e_n_n_i_s]

So if I understand it correctly, there is one intake and exhaust into the flame and another intake and exhaust that circulates the interior cabin air around the combustion chamber. That's an excellent design principle. Is the combustion chamber completely sealed, i.e. air can only enter the flame from the intake coming from outside the cabin and can only exhaust out of the exhaust vent going to the outside of the cabin?

[ConradG]

That is correct. So long as your pipes are intact.
With the "hydronic" or water boiler-coolant heater, the whole thing can be mounted outside and the water piped wherever you want it. The little controller has to be inside of course but the fuel pump, water pump and the boiler itself is ussually mounted to the frame of the tucks, down in the nasty road #$% when used on trucks. If they come with exhaust and intake piping for the cobustion air if you want to put it in some out of the way place. I will probably put mine in the engine room and pipe in air and out exaust. The worst case situation would be that the combustion chamber would get flooded in the case of serious blue water or capsize. Still now way of flooding the boat. The other option would be to mount the unit above deck (in a deck box or lazerette) and pipe the water through but then any expansion tank would have to be raised to that level. Six of one/half dozen of another...