Diesel Heaters - Forced Air & "Hydronic"

[footrope]

I have an older E38 and I am going to add heat this fall. Been looking at mainly Espar and Webasto forced air systems. The large ducts and the compromises involved in routing them in this boat are causing me to re-think that idea and look at water systems. One advantage of the "hydronic" systems is that I could also heat domestic water (I have a 12 gal. water heater) with an additional heat exchanger.

I would appreciate some input about the quality of heat or any other differences you've discovered between the two methods. Are they equally effective against condensation? Here in the Great Northwet we sometimes wake up with water dripping in our faces in winter.

Thanks,

 

[Mike.Gritten]

Craig,

we installed an Espar D5LC last December and live aboard in Vancouver, BC. We bought the unit used so choosing one type over another was not part of the equation. Our 35 mkII had an ancient kerosene fed Wallas forced air furnace installed in a hanging locker when we bought her. We removed that a couple of years ago, but the 4" holes through bulkheads and under the settees that carried the Wallas ducting meant we had most of the nasty work done for the Espar ducts. I will have to post some pics of the installation (been meaning to take some photos for just that purpose). We have friends at the dock with both types of systems (forced air/hot water) and can comment on pros and cons. Our system uses fresh outside air which is then heated and fed into the cabin, forcing stale inside air out through passive vents. I really like this - the boat smells great and is toasty and warm. The fan moving the air through the boat is part of the Espar unit which is located out in the starboard lazarette locker and does not make any real noticable noise in the living spaces of the boat. Takes about 10 minutes to warm the boat on a really cold day to more than room temperature and then switches down to a low setting on the fan speed to maintain the temp. As boat temp reaches required setting, fan motor might actually shut right off, starting up again as required when boat cools down. Just like the furnace in your house. The duct runs keep the areas of the boat that they run through nice and warm too.
With the hot water systems, the fans are much smaller and are (usually) located in several areas throughout the boat. The actual Espar (or Webasto or ???) unit is much smaller as it only has to pump water through relatively small hoses, not feed 4" ducts for air to flow through. Obviously, the holes required to run these hoses are much smaller than for ducts, but some ducting may still be required (depends on your particular installation). The hoses carrying this hot water still heat the areas they travel through enough to chase dampness from your lockers. Our friends in a trawler actually zig-zag the hoses throughout the space under their sole for just this reason. The warmth comes from automotive style "bus heaters" containing a heater core and fan to push air through the core. These fans can be manually or thermostatically controlled. They are fairly quiet. Only air that is already in the boat is heated. Works really nicely and can be "zoned" quite easily - again depends on the system purchased.
If I had a new boat and money was no object I think I would opt for the hot water version, because I am not a fan those big 4" holes through the bulkheads. I am sure though, that you will be happy whichever way you go.

 

[stbdtack]

Diesel heat....

I've had both and either one will make you a very happy boat dweller in the colder months. The differences I noticed were mainly that the forced air heater will get your boat up to temp quite a bit faster than the Hydronic system. Having to heat the water first to warm the heat exchangers takes more time. After the heat up time, its basically the same comfort for both. Hydronic is much easier to run the water lines and you will save on installation costs. Although the heat exchangers will add to the total costs. Great benefit is you can have hot water for showers.

If you go with the forced air model I recommend keeping the duct work as simple as possible. It keeps the install costs/complexity down, and the blower motor in the heater will not suffer from back pressure that lots of ducting will produce. Also be very careful not to get a heater thats too big. I have noticed that the Dealers tend to spec a lot of BTUs for boats. Its better to have a smaller heater running longer than a big one that cycles on and off (requiring the glowplug to be energized)

I had a 15,000 btu Espar forced air that kept my 41 foot center cockpit ketch toasty and dry in single digit Annapolis winter temps. It had 2 vents and I used a small 12volt fan when I wanted warm air into the aft cabin (impossible to get ductwork there) Was cheap and worked great.

I'm considering a small espar for my 38 and if i do i will most likely just have one vent with adjustable louvers.

BTW either of these heaters will run much cleaner and longer on kerosene. Consider a separate tank for the heater(Nobody seems to do this). Save the expense of altering your existing tank. I used a regular jerry can with a top that would allow the fuel line to fit in. Easy to fill and remove for the summer months. 5 gallons would run the heater for 4 days continuous in freezing weather.

Hope this helps....

 

[footrope]

Great responses

Thanks for the input, several nuggets there I had not thought about, like the radiator effect of running the water hoses. Hodo runs his Espar on kerosene and swears by it. Initially, I think I will have the diesel connection done by the pros and see about a day tank for kerosene later. I would like to see pics of duct runs for the air system, if you get time to post them.

I am waiting (too long) for a quote from a local mod shop. I'll probably get two more before I decide on who and which, but I am leaning towards the boiler driven system now, even at a greater cost. The single outlet option on the air system probably would work, but where in the boat would you put it?

The difficulty with a forced air system my particular 38 is my equipment and its location (electronics, batteries and inverter/ chargers, refrigeration) and then the general layout of the early 38 interior has its constraints. Running the 3" or 4" air ducts from the stern is going to drive up costs in new finish cabinetry and I'd also have to relocate some nav gear. I'd have to give up storage in any scenario. On top of that, I like the interior the way it is - with the 80's-style wine rack and lazy susan liquor (and olive oil) storage spaces. I hope a huge can of beer doesn't come down and crush me today.

The system I'm currently getting a quote for includes boiler, expansion tank, and two radiators. I already have a "Red Dot" engine coolant-supplied heater in the mid-cabin, which would be replaced by a new radiator and low draw fan. The plan is to install the second radiator in the bulkhead under the steps, in a little box. I may also install the heat exchanger that would allow the diesel heater to warm the domestic water, possibly eliminating the need to run the engine to take advantage of that other modern luxury - a hot shower. Also, I think we wouldn't always have to run the boiler heat when the engine was running, with that heat exchanger.

So, I'm not committed to the "hydronic" system, but it looks like it'll be a fair trade for the other advantage - the domestic water option.

 

[ted_reshetiloff]

FWIW Craig I have a Mermaid Air system in my 1989 E 38-200. It is located under the port setee seat and displaced a 40 gallon water tank. This system heats and cools the boat very effectively and the ducting was not too intrusive. Downsides are that it only runs on shore power and it displaced a 40 gallon water tank. Plus side is that the AC side of it is absolutely fabulous in the summer heat and humidity on the Chesapeake. Different story for you guys in the NW...

 

[Loren Beach]

Another Heater idea...

Since this thread started with a heater decision for an early E-38, I note that those were the Ericsons with the stock (?) Cole Stove on the forward starboard bulkhead. (I have seen this SS solid fuel heater on several of these boats and figure that it was a stock item or at least a very common option at that time.)
The later 38's, with the tri-cabin interior do not have such a dedicated place for a heater, and I have the same situation with a similar interior in our Olson 34. This solution would be difficult for our boat. Oh well.

Considering that the interior of the earlier boats is more "open" perhaps a modern version of a bulkhead heater might worth a look.

An E-32-3 in our club has a new installation of a propane heater that uses outside air for combustion AND has a multi-speed fan for expelling heat from the double-wall stove inside the boat. I came down the coast on this particular boat this summer and it was marvelous in the Pacific for damp and chilly nights (and foggy days!). The flame is visible and can be varied, as well.
Here is a URL for this heater: http://www.dickinsonmarine.com/


And attached are photos of the inside unit and the cabintop stack. This particular boat already had a propane system for cooking, so only a tee inside the aft tank compartment and another line needed to be run.
Cheers,
Loren in chilly Portland, OR

 

[footrope]

Bundle up with the original stove...

Good point, Loren. The Cole Stove, a quaint, wood-burning appliance, is still installed high on the forward starboard bulkhead of the "Project." And I've used it a couple times. It's really too dangerous for my taste, just from the likelihood that the cabin ceiling will burst into flames if you load it too full or give it too much air. There's probably another thread with more of my fears about CO and how "needy" the stove seems to be in actual practice. Don't mind the mess in the picture.

I've thought about propane, but the original 38 interior just doesn't have a decent bulkhead to install a cabin-mounted radiant heater upon. There might be a spot if I was willing to make significant changes, but I am squeamish about modifying the interior to make it so. I really like the interior the way it is and my dreams for this boat are purely inside waters and perhaps some coastal. Doesn't propane tend to throw off water vapor? Maybe it wouldn't matter if the boat is kept warm.

I am more appalled than I expected to be at the prices I'm being quoted for installation of the hydronic units. And I'm confused about how many BTUs I really need. I am planning for 2 heat exchangers with hot water option, and I've been quoted the Hydronic 5 (17K BTU) and the 10 (32.4K BTU). $1700 difference between them. The larger unit features higher negligible fuel consumption, higher electrical draw, and the ability to easily add a third zone further forward - for those Alaska-cold nights when I reach my active 70s.

I am prejudiced towards the Espar, since I am sold on Boat Electric's production relay/control panel that consolidates all the wire terminations on a 10x10 inch board. I suppose a Webasto dealer could do that, but I haven't checked with any.

Anyone ever hear of Arctic heaters? They're supposed to be marine from the beginning rather than a marinized truck heater. Probably more expensive ...

 

[footrope]

FWIW Craig I have a Mermaid Air system in my 1989 E 38-200. It is located under the port setee seat and displaced a 40 gallon water tank. This system heats and cools the boat very effectively and the ducting was not too intrusive. Downsides are that it only runs on shore power and it displaced a 40 gallon water tank. Plus side is that the AC side of it is absolutely fabulous in the summer heat and humidity on the Chesapeake. Different story for you guys in the NW...

Hey Ted,

We actually have a few days every summer when the humidity reaches like 60% and the temperature is above 80F at the same time. That's when we hide our red faces under biminis, drink a lot of cheap, cold beer, and generally wilt like cooked spinach. I think I would need the cooler if I was anywhere near the midwest or further south. No doubt about it.

 

[Ernest]

We have also installed (ourselves) a Mermaid reversible air conditioning unit which runs on AC (at the dock only) which has done a wonderful job of cooling and heating at a low price. It takes up the space that the hanging locker did before. We have a 3" short duct forward and a 4" duct facing aft. Had it a couple of years now and operates automatically and flawlessly on a thermostadt just like your home. Draws under 8 amps in our E-35 when working. No Oxygen or CO problems apply. Ernie Schlesinger

 

[Mike.Gritten]

Craig,

I think the unit you're referring to is the Ardic (with a "d" instead of the "t") heater. Here's a link to Scan Marine's description. I have heard of several boats locally in Vancouver that use them with good success. I like the idea that you can circulate hot water through the engine and that the unit apparently does both hot water and forced air! Take a look....

http://www.scanmarineusa.com/Ardic952D.htm

 

[footrope]

More thoughts

More great input, thanks. I went to the Scanmarine website and the unit looks good. Twenty-two pounds for the Ardic is kind of scary, but it would help me balance out my port list. I am sticking with the Espar though. One track at a time. Just how well was your boat insulated during that single-digit weather?

I have to make a decision soon (if I want a post-Christmas shakedown cruise) about two quite different systems that I have been quoted. I've spent time at the distributor and called them for some system and options clarification. And then well over an hour on the phone with each installation company discussing (and sometimes changing) the details of their quotes. I am quite satisfied with the integrity of each, and with their committment to producing satisfied customers. Their opinions and experience don't always agree, so I'll lay out a few items and ask you to comment on your experience or hearsay.

Intended usage range - Pacific NW or West Coast - year round cruising. Summer to Alaska via the Inside Passage - someday. I want to be able to be away from services (fuel, water) for at least a week at a time - 2 weeks in summer.

Same-same in the two systems: Two cabin heat exchangers, one aft under the cabin steps and above the top of the engine, one at midship, floor-level under the aft stbd. settee seat. Domestic water heating.

Hydronic 10 has 1 year or 1000 hour warranty, the Hydronic 5 has a 2 year or 2000 hour warranty. I just noticed this last night in the distributor catalog after hanging up with the "10" people. Didn't get a chance to ask him about that - perhaps a good question for the distributor. The "10" people emphasized satisfactory heating performance. The "5" people emphasize reliable, low maintenance systems that do the job. The distributor sides with the "10" people, by the way.

Lots of anecdotal customer evidence from the "5" people about the suitability of the smaller unit, even in boats up to ~42 feet, supported by your opinions in earlier replies, on air systems. With our two-heater plus domestic water needs, the smaller unit seems like an adequate choice. The big debate - will the "10" burner "coke up" faster, if it is loafing much of the time, than the "5" which should spend more of it's lifetime running on Hi?

The domestic water option I settled on with the "5" would add a pump to circulate the engine coolant through an added coolant-to-coolant heat exchanger. This limits the draw off of BTUs from the cabin, but extends the time to heat my 12 gallons. The plan is to also heat the engine block rather than put any more time & $$ into plumbing around the engine. Engine waste heat would still heat water while motoring. The "10" system would eliminate engine waste heat to domestic water by putting the Espar coolant through the water heater. Only way to heat the domestic water away from 120 VAC is with the Espar. Eliminates a c-c heat exchanger. Good way to ensure we use the thing all year round. Adds hours against that 1000 hour warranty.

Final differences: "5" insists on dip tube in fuel tank, "10" likes to tap into the engine fuel system after the first filter. "Never" had a problem with it. I keep the boat in the mouth of a river. I am more worried about the engine quitting than not being able to run the heater on the last dregs of the fuel tank.

With the "5" I'm probably stuck with the two cabin heat exchanger system. With the "10" I could easily expand to a third cabin heater in the future.

The "5" would be installed in the stern lazarette, up high and out of the way. A bit problematic for installation and servicing, maybe. Flex hose for the exhaust. The "10" would be way forward in the starboard laz. and would take up about half a cubic ft. of storage. It would be enclosed somehow to keep stuff away from the hot parts. On the "10" they may recommend a hard exhaust system - add $ for welding/bending one up.

Price differential - mostly parts. The total on the "10" with the special pump w/check valve on the fuel system is $2,200 more than the "5"

I appreciate your input on this. Not an easy decsion. I've learned a lot from your experience and from talking to the companies. Thanks!

 

[stbdtack]

insulation...

Hey Craig,
My Morgan 416 Is a solid glass hull(extremely thick) and the deck is thick glass with a plywood core and a thin glass headliner. No real insulation to speak of but the air space above the headliner probably helps a lot.

My friends put a webasto 12000 btu air heater on their Catalina 42. Granted its not too extreme in the SF bay area, but when it's down in the low 40s-high 30s, he said it would still run them out if it were left on continously.

Another thought if you run on diesel is some soot will exit the exaust. My friends had their exaust on the inside of the walk-thru transom and they had to clean every week or so when it was running. (kerosene will produce hardly any soot)

I'm happy to see you're researching this so thoroughly. Really benefits the group.

 

[Loren Beach]

Fuel for thought...

Hi Ben,
Interesting comment about using kerosine. A while back we spoke to the folks at Boat Electric in Seattle about fuel, if and when we put in a forced air $y$tem.
I asked about a rumor that all these units ran cleaner on kero.
We were told that for the little trouble of installing a separate kero tank (a small capacity one, in our situation) the furnace would run a lot cleaner and the glow pin would last lots longer. Clean-as-possible sourced "diesel" is a biggie with any of these units.
Now all I have to do is find the approx. 2K dollars for the furnace parts kit...


Good luck on your installation,
Loren in PDX
Olson 34 #8

 

[stbdtack]

heater...

Hi Loren,
I ran my Espar on Kerosene only. I did open the heater up once a year and found very little soot to be cleaned up. The glow plug was always clean. I used a 5 gallon container and could buy kerosene by the gallon at an Eastport gas station in Annapolis so it was pretty convenient.
The problem with the earlier diesel heaters was that they were designed in Europe to run on #1 diesel which is common there. We get #2 diesel here which is not as clean burning. I think the newer heaters have been designed to run satisfactorily on #2 but it still doesnt burn clean, which is evident with my friends new Webasto unit and the soot near his exhaust.
I used to fill my diesel tank with about 15% kerosene every spring. The Perkins would start and run so smooth. That engine has close to 5000 hours on it now and runs perfectly.
I think finding a place to buy it from the pump is the biggest challenge....

 

[footrope]

Decision!

We'll will have the Espar Hydronic 5 (17,000 BTU) water circulating heater system installed. We'll have two cabin heat exchangers (MSR) of about 9,000 BTU each. They have two fans and fan switches with OFF-LO-HI settings. One temperature control zone with the thermostat amidships - on the starboard bulkhead where the lazy-susan is installed.

Domestic water will be heated by a "triangle tube" heat exchanger installed on the outlet of the water heater, with an anti-scald mixer. Essentially we'll have "instant" hot water. This means that the water heater is still heated by engine waste heat when the engine is running. We'll have to run the Espar heater to get hot water unless we've motored the day before, or have been connected to AC power. An additional circulation pump is not required, as we will not be passing heat from the Espar heater circuit to the engine coolant circuit to heat the water in the water heater. I'll put up a diagram after we're done with the installation.

The choice of the Hydronic 5 is supposed to slightly undersize the system so that it spends more of its life on a high heat output, rather than the lower output. The hope is that there will be less carbon fouling of the glow pin. We'll see if that works. I think the Hydronic 4 (14.700 BTU) would be good enough, but the installer won't back that up. We're not live-aboards so the heater will probably last beyond the 2-year (or 2,000 hour) warranty.

Fuel pickup will be via a new pickup tube in the engine fuel tank. Later I may install a kerosene day tank, if sooting is a problem.

I appreciate all the input from those of you that have experience with diesel heaters on boats. I'll let you know how the system performs in future posts. We are taking the boat into Lake Union on the 11th and hope to get it back a few days after Christmas. Hopefully we'll have a shakedown cruise over New Years.

Thanks,

 

[Sean Engle]

Espar is nice...

I had an Espar on O Barquinho - and really liked it.

When I purchased the her, I wanted to minimize the number of fuels present on the boat, and looked for a forced air diesel system that drew off the main tank. That resulted in two fuels: diesel and propane.

During the winter I left an electric oil-filled radiator (and a fan), and put the Espar thermostat at the bottom setting in case of a cold snap or electrical failure at the marina. My mold disappeared.

The only other issue I can think of is resell - Espar is a well known brand/feature. The buyer of your boat will ID it immediately.

//sse

 

[Graham Cole]

I would consider the kerosene option. Just put a D5 on the flybridge of a Riviera 43 and had bad soot from the diesel. Bought a 5 gallon plastic outboard tank and installed the espar fuel hose barb in the pickup. No soot, hotter burn and faster ignition.

 

[footrope]

Slight delay...

Visited the boat again today and the good news is that the heater is going to work fine. Installation is basically done. Made some electrical power consumption measurements with the various fan settings. Inspected the boiler-burner exhaust muffler we agreed was required to be good neighbors in the marina or anchorage. The exhaust is considerably quieter. The instant hot-water heating idea seems like it will work fine also. We're messing with the mixer setting a little.

The bad news is that the giant construction paper post-its they put down on the sole to protect the finish - took part of the finish off. A poorly applied varnish coat (by PO) seems to have come off in small patches. So we'll be a few days more and we'll see about splitting the cost of some sanding and varnish.

 

[Loren Beach]

How many BTU's ?

Here we are, in the "temperate" NW... having been snowed in for several days during Christmas week (that's a first).
Now in January the weather's more normal, i.e. temps in the 30's and showers in the near forecast.
We are wishing that we could spend some weekends on the boat and therefore needing some cabin heat.
If and when the dollar gains some oomph and prices of these systems normalize a bit we will start shopping for a Webasto forced air (or similar) setup.
The big unknown is just how many BTU's is "enough."

The vendor sizing guides are vague enough that they can blame all problems on the customer.
It's partly the money, and partly just trying to figure out how it would work in the Real World and not just in the pretty brochure.
If going with Webasto, is the 2000 enough for spending nights on the boat in the NW "shoulder seasons" and not trying for the December/January freezing season? We get a lot of acceptable weather, i.e. temps in the 40's in Oct and early November and again in late February and onwards. The island docks are mostly deserted and it is a nice time to be there... IF you can really warm up the interior to "home comfort" levels.

We have a relatively large "volume" interior in our 34 footer, but almost zero room for any extensive duct system -- no room to run 3" duct work forward of the galley and nav desk because there is no room along the hull behind the minimal cabinetry.

It would be useful to have some feedback from folks with similar size interiors and heaters. What with boats being "sized" according to displacement, I would guess that anything displacing similar to our 10600# would be kinda-sorta comparable. Maybe.

These little cylindrical furnaces seem to come in 2000 and 3500 BTU sizing. Duct sizing would be an issue, also. If the larger output furnace "requires" larger ductwork, that's not a good thing for us.

Your experiences??

Thanks,
Loren

 

[rwthomas1]

Hey Loren, didn't you convince me to install a propane Dickinson??? I can say it works quite well for the scenarios you describe. I just couldn't find a way to work out the ducting for a forced air heater, the prices were pretty steep, and the hydro systems even more so. I'm happy I went with the Dickinson, and now I have a good reason to convert my stove to propane too. RT