Heating options - MF805

[AHoy2]

I intend to add cabin heating to my Jeanneau MF805 and have been considering the relative merits and issues of direct air heating v. water heaters + matrix. I am getting conflicting advice from suppliers and would appreciate any views from the forum.

The boat is used for coastal/channel fishing and cruising year round, including overnighting and short cruises away from shore facilities.

Option A.
The boat already has an engine fed hot water circuit for the OE calorifier and screen demisters, my initial plan was to add a heater matrix to the circuit and incorporate a diesel fuelled heater e.g. Eber Hydronic 5, Webasto Thermo Top C or Mikuni MX40. In addition to heating and hot water this would also provide engine pre-heat capability, something I consider a desirable feature.
Pro: features per requirements, cheaper (slightly), simpler installation; heater can be installed in engine bay, short ducting runs.
Con: additional water circuit elements to consider re. possible engine related failures (low risk with good maintenance), matrix fans are noisier (according to one supplier), demand on the heater may not be enough to prevent frequent coking up of heater burner (according to two suppliers) although I have not experienced this problem on similar vehicle based systems.

Option B.
Diesel fuelled air heating using 2 or 3 KW Eber/Webasto/Wallas unit with 2 or 3 ducted outlets.
Pros: quieter (I'm told), near instant heat availability, lower fuel and battery use, independent of engine cooling circuit.
Cons: more expensive, no hot water without engine being run, routing for ducting to fore cabin doesn't appear straightforward or tidy, long(ish) ducting runs.

I want to avoid running heater ducts via the engine bay due to the reduced fire resistance this could cause and also increased engine noise transmission.

Any MF805 owners able to comment on their installations?
Any other relevant advice/comments welcome.

AHoy2.

 

[pissativlypossed]

Go for option B, We had a Eberspacher 3 on our MF 805 and it was more then up to the job. You will need to run your engine to produce any heat using your first option not something you will want to do if on your berth or while anchored for fishing etc. It's not good policy to run a diesel engine with no load as it can cause glazing of the cylinders.
We chose a Wabasto installation on our Prestige 36 as the Eberspacher proved to be somewhat temperamental.

 

[LittleShip]

I'm in the process of installing a wet system on my boat, purely on the grounds that I can have hot water without running the engine. Two showers on board and the cylinder is empty, so this was my criteria for going wet.

Tom

 

[mainshiptom]

What about option C?

Small genny that can fire up a fan heater or small radiator?

My boat is all electric which is good on anchor or on the go as well as in a marina that I get electricity fed on board and can use the heating, where people with wet systems fed by diesel have to burn diesel as well as pay for electricity?


Tom

 

[Nautorius]

Option D! Add a Wallas twin Diesel Hob with Convector. Not cheap at about £1000 but gives you great cooker and heater in one!

See HERE!

I had this set up on the Aquador 23HT and it was amazing and very frugal. It does not smell either and is very reliable...unlike ebers!

Cooker and heater in one...great buy!

Paul /forums/images/graemlins/smile.gif

 

[Sneds]

Looks great, wonder if I could have one in place of my single electric (240V mains only) hob?
Combined heater cooker would be a load cheaper than an Eber, wonder if some heat could be ducted out to the cockpit area? (sports cruiser)
I'm pretty crap at DIY so would need it fitted!

 

[wp1234]

I’ve got option B in my 805 Esber in the Laz , one duct leads through the engine bay forward to outlet under the forward cabin stairs and spurs off to another outlet within forward cockpit seating base - very quiet when running, simple installation and keeps us warm as to ashore or at sea . PM me if you want me to take a few pics for you.

 

[Seadee]

I've got a Webasto Airtop 2000 in my MF805. It's mutts nuts. Dead easy to fit yourself if you're half way DIY inclined. Just take your time. Pics here if you want to look - http://seadee.co.uk/photo/thumbnails.php?album=1

PM if you want any more details.

CD

 

[AHoy2]

Thanks for the responses. I discounted the generator option on the basis of noise, weight, relative space requirement and cost/availability of diesel units (I don’t want to carry petrol other than for the tender outboard). I also intend to replace the gas hob with a diesel model at some stage so eventually no LPG onboard for an LPG genny. The Wallas hob heater option doesn’t work with the 805 galley arrangement, neither does it get heat forward so had to drop that option.

Ref. “pissativelypossed”, the purpose of the water heating system is that the engine doesn’t have to run to obtain hot water and heating, the EberWeb unit does that and also provides a nice warm engine so no more cold starts. It also keeps the engine operating temperature up when running at light load. As mentioned by “LittleShip” it gives an always available hot water supply.

The air heater approach seems to be the default method used by Jeanneau and aftermarket installers, to the extent that a dealer advised if I sell the boat it is what buyers will expect to find fitted. Eber technical support did some basic thermal calcs for me and reckon I could just be running the Hydronic 4 at enough load to avoid the burner gunging up, providing I liked tropical cabin temperatures :>) . Their ideal solution (which I agree with) is if I really want water heating– fit both systems and run the water heat at full bore for initial engine, water and cabin heating then shut it down other than for “at rest” hot water replenishment, use an air heater for general cabin heating.

It looks like the air heater option is the route I will take, with a plan to maybe fit a water heater unit at a later date if a “well priced” unit comes my way. Pricing seems to be lower for an Eber air heater kit based on quotes so far.

Ahoy2.

 

[AHoy2]

Thanks wp1234 and Seadee for the 805 specific info.

 

[AHoy2]

A bit of a late follow-up on this topic but thought I would share my variation on MF805 heating. (A bit PBO like)

I opted for an Eberspacher Airtronic D2 unit installed in the lazarette on the engine bulkhead (similar to other installations mentioned here).

I installed the heater to starboard of the centreline, leaving the gearbox/shaft access panel clear for maintenance work, then ran the air ducting up the starboard side out-board space. The limited heat from the insulated ducting provides frost protection for the water tank, pumps (3), galley tap and water piping in this area. The ducting then enters the engine bay on the forward bulkhead and is feed via a Y-connector to the forward dinette seat base for main saloon heating and out to the forecabin at low level through the storage area beneath the battery switches. The forecabin air can be directed out into the cabin or at the wardrobe area to air clothing.

ISSUES:
a) The Eberspacher marine installation guide specifies an air ducting "heater rating" to ensure adequate air flow through the heater. It was a challenge /forums/images/graemlins/mad.gif meeting this figure using the 60mm ducting in the kit.
b) Installing the double-skinned exhaust run with a swan neck to the hull skin fitting was also a pain (literally) - recommendation: fit exhaust pipe inner to skin fitting before mounting the skin fitting to hull and slide on outer exhaust pipe skin after pipe run is established.
c) The pre-moulded Jeanneau fuel tank take-off points are very thick (10mm), a bit of creativity is required to mount the fuel pick up pipe at this location using the standard mounting kit.

I placed the timer/control panel in the helm area (left of wheel) and the thermostat in the companionway (not visible in pic).

Some temperature figures for anyone interested.

Ambient 13 deg C

At "power" setting:
Primary air outlet (saloon) air temp 85 deg C
Secondary air outlet (forecabin) air temp 70 deg C
Exhaust outer skin temp (at first bend) 106 deg C
Exhaust gas temp (at skin fitting) 220 deg C
Exhaust gas temp (50mm from skin fitting) 100 deg C

At "medium" setting:
Primary air outlet (saloon) air temp 80 deg C
Secondary air outlet (forecabin) air temp 65 deg C
Exhaust outer skin temp (at first bend) 75 deg C
Exhaust gas temp (at skin fitting) 115 deg C
Exhaust gas temp (50mm from skin fitting) 30 deg C

Keep items from falling on the exhaust pipe and fenders/dinghys clear of the exhaust outlet!