Eberspacher fresh air intake in cockpit?

[webcraft]

Still trying to work out where all the bits of the Chinaspacher are going.

The heater itself will be in the engine compartment.

Hot air ducting is in, the exhaust will exit into the lazarette then out through the cockpit coming.

I want the intake air to come from outside, not in the boat.

There are no cockpit lockers, but am happy to give up some space in the starboard quarterberth (which is just storage) . My idea is to have the intake hose come up into the quarterberth then out through the cockpit side aft of the morse control but without protruding into the cockpit.

To do this I would need to create a recess. My worry would be making everything watertight in case we shipped a green one and filled the cockpit.

Alternatively, I could extend the intake hose across the quarterberth against the underside of the cockpit seat and up into the cockpit coming (on the opposite side to and well away from the exhaust)

The intake hose is quite short, what could I extend it with?

- W

 

[Arcady]

Still trying to work out where all the bits of the Chinaspacher are going.

The heater itself will be in the engine compartment.

Hot air ducting is in, the exhaust will exit into the lazarette then out through the cockpit coming.

I want the intake air to come from outside, not in the boat.

There are no cockpit lockers, but am happy to give up some space in the starboard quarterberth (which is just storage) . My idea is to have the intake hose come up into the quarterberth then out through the cockpit side aft of the morse control but without protruding into the cockpit.

To do this I would need to create a recess. My worry would be making everything watertight in case we shipped a green one and filled the cockpit.

Alternatively, I could extend the intake hose across the quarterberth against the underside of the cockpit seat and up into the cockpit coming (on the opposite side to and well away from the exhaust)

The intake hose is quite short, what could I extend it with?

- W

Why not let it draw air in directly from the engine room - which presumably has a fresh air inlet from outside? That way you won’t need any ducting on the inlet side.

 

[Wing Mark]

Why not let it draw air in directly from the engine room - which presumably has a fresh air inlet from outside? That way you won’t need any ducting on the inlet side.

Because it will smell of diesel engine?

Mine is drawing air from a cockpit locker.
I'm tempted to make it draw from the back of the aft cabin.
That might move some air in a dead area, and avoid any smell from wet mooring lines festering in the locker?
Not been an issue yet so I nay never get around to it.
There's always going to be fresh air coming into the boat and warm, moist air leaving via the cabin vents.

 

[SandyP]

There's 2 air intakes, hot cabin air and combustion air

They are designed to heat/reheat cabin air, you loose a lot of heat feeding in fresh cold air all the time (important in freezing conditions). But brilliant when recirculating

The combustion air intake risk is the possibility of fumes blowing back out of the combustion chamber

 

[dankilb]

They are designed to heat/reheat cabin air

Nope

 

[jdc]

Nope

Nope - and not courteous, and stupid as well. FFS!

 

[Plum]

There's 2 air intakes, hot cabin air and combustion air

They are designed to heat/reheat cabin air, you loose a lot of heat feeding in fresh cold air all the time (important in freezing conditions). But brilliant when recirculating

The combustion air intake risk is the possibility of fumes blowing back out of the combustion chamber

They are not specifically designed that way. You have a choice. In my experience it is far far better to heat air drawn from outside the cabin to heat the cabin. Makes for a so much better dryer environment.

Www.solocoastalsailing.co.uk

 

[NormanS]

They are not specifically designed that way. You have a choice. In my experience it is far far better to heat air drawn from outside the cabin to heat the cabin. Makes for a so much better dryer environment.

Www.solocoastalsailing.co.uk

And uses a LOT more fuel.

 

[Plum]

And uses a LOT more fuel. ☹

Yes, it uses more fuel. In the winter if sleeping on board I keep mine on low and it cost less than £2 and in the morning everything is dry. I prefer this to saving a proportion of £2 and having condensation. We all have a choice.

Www.solocoastalsailing.co.uk

 

[Laminar Flow]

As Plum said. The colder outside air is dryer and the furnace keeps up a positive pressure inside the boat evacuating high moisture, warm air.
I, retroactively, hooked our Webasto up to a vent in the cockpit which may can be screwed shut in heavy weather. It made a significant difference to the amount of moisture beading off the aluminum window frames.

Webasto and Eberpachers were originally developed to heat vehicle interiors. For this they were commonly mounted outside, often under the carriage, and from whence they took their air.

 

[webcraft]

There's 2 air intakes, hot cabin air and combustion air

They are designed to heat/reheat cabin air, you loose a lot of heat feeding in fresh cold air all the time (important in freezing conditions). But brilliant when recirculating

The combustion air intake risk is the possibility of fumes blowing back out of the combustion chamber

The combustion air intake is open at the back of the heater (no ducting) isn't it?

- W

 

[ChromeDome]

Be aware that air flows (both combustion and heated) must not be restricted more than specified as it would affect the device's function (commonly overheating). The ducting diameter, length, number of bends and vents fitted will influence this.

For your inspiration the kind people at Butlertechnik (not connected) shared this booklet: https://www.butlertechnik.com/downloads/Webasto_Install_Instructions_Marine_heating_systems.pdf

 

[dankilb]

They are not specifically designed that way. You have a choice. In my experience it is far far better to heat air drawn from outside the cabin to heat the cabin. Makes for a so much better dryer environment.

Www.solocoastalsailing.co.uk

Nope - and not courteous, and stupid as well. FFS!

Not my intention of course - but it got the point across, as subsequently elaborated by posters with more time/knowledge!

Recirculating a diesel heater instal is, IMHO, akin to epoxying your car heater control to recirc - only ok if you like sitting in a humid fug all the time.

 

[webcraft]

So, yeah, I said at the beginning I wanted to take the fresh air from the cockpit.

I was really wondering what the best way to do it was. 60mm is a big hole.

Up from the heater is the cockpit sole. Behind it I could run the duct through a shallow locker under the quarterberth then vertically up to exit under the cockpit coaming. About 1.5m run with 2x90 degree bends. Would that be OK? I would need a closeable vent to keep water out on passage or in driving rain.

- W

 

[Wing Mark]

...

Webasto and Eberpachers were originally developed to heat vehicle interiors. For this they were commonly mounted outside, often under the carriage, and from whence they took their air.

The air heaters mostly started in buses, truck cabs that sort of thing.
They have a gasket around the exhaust and combustion air intake. Those are the 'outdoor parts' the cabin air inlet and outlet are on the indoor side of that gasket.

I've had a car with a Webasto under the bonnet, but that was a 'wet' heater.

If you want some fresh air in the boat, it's not hard to do that separately, I have quite a lot of vents open unless there's green water coming in all directions.

If the cabin air is drawn from 'outside' it could be a concern that the inlet and outlet are affected by wind pressure. I haven't found this an issue yet, but then I'm running my heater 'flat out' now and then in a marina to give the boat a dry-out and for my comfort while I'm doing jobs with the hatch open.
If running the heater 'turned down low' for longer periods, you might find that the wind affects the blown air relatively more? If I find this is an issue, I will drawn the cabin air from the cabin. I wonder if one day I'll be holed up somewhere with a gale blowing against the heater's 20 watt fan?

Whether you draw the cabin air from indoors or out, the only way water leaves the cabin is by warm damp air escaping. Apart from mopping up condensation and squeezing the cloth into the sink I suppose!

 

[Wing Mark]

So, yeah, I said at the beginning I wanted to take the fresh air from the cockpit.

I was really wondering what the best way to do it was. 60mm is a big hole.

Up from the heater is the cockpit sole. Behind it I could run the duct through a shallow locker under the quarterberth then vertically up to exit under the cockpit coaming. About 1.5m run with 2x90 degree bends. Would that be OK? I would need a closeable vent to keep water out on passage or in driving rain.

- W

You can get 100mm ducting for domestic extractor fans?
Also flat plastic 'box trunking' See screwfix or toolstation websites.
The flexible trunking is basically steel coil and very thin plastic, I wouldn't choose it for a boat.
Flexi aluminium ducting is on ebay for the purpose, I've also bought (for other purposes!) from Merlin Motorsport
I would work on the basis of not wanting too much resistance to the airflow, so big pipe, easy curves where possible?
Probably no harm in just drawing air from one side of cockpit locker and putting a vent in the other side? That way if you get a wave in the cockpit, hopefully the water only gets in the locker, not the heater.

 

[Graham376]

I've had Ebers and Mikuni on four boats and have tried them both ways, circulating and outside air. The latter gives a much drier boat and expels cooking/stale smells etc far better with less condensation on windows.

 

[webcraft]

For clarification... the boat has no cockpit lockers, just quarterberths.

- W

 

[Wing Mark]

I've had Ebers and Mikuni on four boats and have tried them both ways, circulating and outside air. The latter gives a much drier boat and expels cooking/stale smells etc far better with less condensation on windows.

You could probably get that benefit with simple ventilation.
Personally I'd want the ventilation, even when it's warm enough not to want heating on.

 

[mrangry]

I just took inlet air from one of the feeds to the engine compartment on the transom.