Webasto installation in Beneteau Oceanis 40

[hanst]

Hi,

I'm planning to install a Webasto Air Top Evo 5500 in our Oceanis 40.
Most of the ducting I'll manage, but I can really use some pointers on the part between the aft locker through the aft starboard cabin to the bathroom.

If any can tell what the 'default' way to do this is it would be a great help. It will help to avoid me having to cut into the woodwork to find out that it won't work.

My plan so far is this: https://ibb.co/3C9yXQz

Grey = 90mm
Orange = 60mm

Thanks in advance!

[Zamba]

Hi. I've got a 3-canin Oceanis 43. I believe they are very similar to the Oceanis 40. I believe my hot air pipe runs along the hull under the bunk in the sb aft cabin (squeezed in a gate between the water tank and the hull), and then under the false bottom of the cupboard towards the aft bathroom. The main challenge for me was to run the pipe across the fw bathroom to the fw cabin. Space was there, but very difficult to reach to fish it through... I'm not sure what your pipe going towards the engine compartment is about. My two aft cabins each have an outlet at their foot ends. I would consider using smaller diversion pipes for the saloon, and a big pipe running all the way to the fw cabin. I always struggle to get decent heat all the way forward. Maybe pipe insulation would be worthwhile, my pipework has no insulation...
Good luck.

[steffan]

I am planning a similar diesel heater installation. What is the best source for pipework and vents?

[hanst]

Originally Posted by Zamba

Hi. I've got a 3-canin Oceanis 43. I believe they are very similar to the Oceanis 40. I believe my hot air pipe runs along the hull under the bunk in the sb aft cabin (squeezed in a gate between the water tank and the hull), and then under the false bottom of the cupboard towards the aft bathroom.

From what I can see I don't have enough space next to the watertank.
Bathroom to underneath false bottom of closet will be ok, but then the next bit I'm unsure of.

As can be seen here:

there's no space on the left. On the right of the watertank I have space, but that would add 4 90 degree corners to the pipe which feels suboptimal.

Another option would be to run it partially through the top-loading cupboards next to the bed and place a wood false bottom on top of it.

Originally Posted by Zamba

The main challenge for me was to run the pipe across the fw bathroom to the fw cabin. Space was there, but very difficult to reach to fish it through...

This part I think I have figured out. Will still be a challenge, but one I know will work

Originally Posted by Zamba

I'm not sure what your pipe going towards the engine compartment is about. My two aft cabins each have an outlet at their foot ends.

I didn't see yet how to get a pipe from starboard to the port side. So I figured maybe to let it come from the back where the air intake tubes for the engine run.

Originally Posted by Zamba

I would consider using smaller diversion pipes for the saloon, and a big pipe running all the way to the fw cabin. I always struggle to get decent heat all the way forward. Maybe pipe insulation would be worthwhile, my pipework has no insulation...
Good luck.

I'm using mostly rubber hosing like this:

which should make getting warm air to the end possible.

[Pete7]

I can't quite remember if its in the Webasto or Enerspacher manuals, but there is a calculator which tells you how many junctions by type, lengths of pipe run and bends you can have for a system to work properly.

Worth having a good read before you buy anything.

That heater hose looks different from the type supplied in Europe which is more of a foil coloured black on the outside. Yours looks to be thicker and therefore offer some insulation value which is needed. The difference in the foil stuff is that without the insulation I could hold the back of my hand in front of the two heater outlets. However, with the insulation that we retro fitted the air from the vent was too hot for my hand after a couple of seconds.

https://www.butlertechnik.com/instal...1s70014a-p1525

[SV__Grace]

From your drawing it looks like the heating unit is installed at the far aft end of your boat and I would be concerned with the long runs creating an inefficient system of lukewarm air coming out of the forward vents (which was happening on my boat when I bought it). Can you install somewhere in the center?

[Zamba]

I realise my pipe indeed runs on the centerline side of the water tank, sorry for the confusion. My heater actually sits athwartships on the bulkhead in the lazarette, so that eliminates one 90deg bend and some bit of pipe run. It was installed by the dealer when I bought the boat. It makes quite a lot of noise in the sb aft cabin though as it sits on the bulkhead, so maybe your suggested position on the hull side is preferable in that respect. The dealer only did a limited "budget" install, so I later added a couple of outlets myself.

[CarinaPDX]

Instead of spending a small fortune on Webasto or Espar consider getting cheap knock-offs from China. Nearly every day I get an email from Banggood.com that advertises an 8kW kit for $170; one time during their big annual sale it got down to $130. I realize that doesn't seem possible, that it must be junk, but I don't think that is the case. They have a range of outputs available. For that kind of money it is possible to consider buying two kits and cutting down on the ducting, and even buying a spare. There are online reviews from western sources so do a little research.

Greg

[ABJ87]

On a boat that size look at a hydronic system.

[CarinaPDX]

Originally Posted by ABJ87

On a boat that size look at a hydronic system.

Yes, the best but most expensive option. If you are willing to pay for German heaters then a hydronic system is preferable. Hurricane has an especially good reputation.

Greg

[Disailor]

All home hot air heating systems us dampers in the ducts to ensure heat gets to all rooms equally. Dampers restrict flow to the nearest outlets progressively getting more & more open as you reach the furthest room.



Industrial systems (often seen hanging from the ceiling) start large & ducts get progressively smaller to increase the velocity.



Because a boat is so far from tight it's ok to close the doors to unoccupied rooms thus sending more heated air to the V-berth.

With one duct systems the heater pulls air from the engine room, heats it & sends it to the areas to be warmed & where it then escapes back to the outside - no need for a return. If all the doors / hatches are closed it may be possible to restrict the amount of air flow thru the heater that it will overheat (most have hi limit shutoffs)

If the heater has a cold air return option (mine does) then it would be a good idea to give the warm air that has entered the room a way to get back to the heater's return duct (increases efficiency).
Air flow is also effected by the diam of the duct & the length. Small diam, long runs need a higher fan speed to keep the unit from hi-limit shutoff.
An HVAC installer may have helpful advise.

[Disailor]

Hydronic systems do away with all that air balancing stuff.

[smac999]

Originally Posted by CarinaPDX

Instead of spending a small fortune on Webasto or Espar consider getting cheap knock-offs from China. Nearly every day I get an email from Banggood.com that advertises an 8kW kit for $170; one time during their big annual sale it got down to $130. I realize that doesn't seem possible, that it must be junk, but I don't think that is the case. They have a range of outputs available. For that kind of money it is possible to consider buying two kits and cutting down on the ducting, and even buying a spare. There are online reviews from western sources so do a little research.

Greg

Yah let’s take Chinese crap and connect it to a flammable liquid while you sleep In a structure you can not leave in a fire. Great idea.

Let’s also power it from a Honda gen on the back deck. Just to make sure we kill off any left over survivors

All to save a few bucks.

[Pete7]

Originally Posted by Disailor

All home hot air heating systems us dampers in the ducts to ensure heat gets to all rooms equally. Dampers restrict flow to the nearest outlets progressively getting more & more open as you reach the furthest room.

The outlets on my Webasto system have dampers so we can change the flow rates. Also by using Y junctions or T pieces you can alter the distribution. For example we have 30% to the rear cabin and 70% to the saloon.

A cold air return will take damp warm air from inside the boat, re-heat it and send it around again. I prefer cold air from outside to be heated and expelled via the various boat vents so the humidity is reduced.

Pete

[Sorcery61]

At a boat length of around 40 feet and when a prime consideration is heat in forward cabin a hydronic system may be more suitable than hot air
Water can move larger amounts of BTU through smaller pipe work
Radiators can be active or passive in cabins
Overall energy budget for batteries is lower as you are not pushing so much air around
Hydronic systems also generally result in drier heat with moisture able to be vented out of boat instead of recycled as air systems are normally designed to do
Perhaps a little further consideration prior to cutting large vent openings and loosing all that storage space