Heater (Webasto/Eberspacher) Air Feed

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ShaunMc

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HI all,

I'm curious how other peoples boats tend to have their diesel heaters piped in? For the HVAC air rather than the combustion.

Mine has the combustion intake from the engine bay - which is vented - and the exhaust overboard so no problem there.

The cabin / HVAC air piping draws from a sheltered location in the cockpit and is piped around the interior. The latter is fine and reasonably balanced but is there any specfic reason why it draws from outside and without a recirculation option? Much like a car there are benefits to both external and recirculated air. Do people have one system and / or the other? What are the benefits / drawbacks to each on a boat?

TIA
 
My car will only stay on recirculate for 5 mins !
Recirculating the same air is not introducing more oxygenated air. The co2 can rise.
It is also said recirculating the air causes it to become clammy.
Mine recirculates/draws from a cupboard inside but does have an air vent on the roof in the cupboard
 
On a boat, heating is very much about drying the contents of the boat, so drawing in the driest air you can find is good.
There needs to be plenty of ventillation to let some warm damp air out.

My car will recirculate air, but it has aircon, which chills the air, drying it, before heating it again.

Boat heating is not big on efficiency!

I don't like the combustion air coming from the living space, at best, when the heater stops you get some fume smell in the cabin.
Ours comes from a cockpit locker only vented to the outdoors.
 
I have mine taking the air to be warmed from the foot of the quarter berth it will heat the cabin quicker and use less fuel ,the humidity does start dropping after a while and you end up with a nice warm and dry cabin.
 
When DIYed my Webasto airtop I had it recirculating taking the air from a void at the stern! This worked fine 90% of the time however during warmer days I would get an overheat error! I think this could be because it was reheating already warm air! I now have it taking the air from the cockpit area. Using this method, it could also be used to bring in cold air into the cabin when you of in warmer climate!

I am planning to now to have both options with a diversion valve
 
TernVI said:
On a boat, heating is very much about drying the contents of the boat, so drawing in the driest air you can find is good.
There needs to be plenty of ventillation to let some warm damp air out.

My car will recirculate air, but it has aircon, which chills the air, drying it, before heating it again.

Boat heating is not big on efficiency!

I don't like the combustion air coming from the living space, at best, when the heater stops you get some fume smell in the cabin.
Ours comes from a cockpit locker only vented to the outdoors.
Click to expand...
+1 that is my experience too.

www.solocoastalsailing.co.uk
 
My Eberspacher, installed by the builders, draws both combustion air and heating air from inside. Drawing heating air from inside is much more efficient, as the air doesn't have to be heated so much to achieve a warm interior. Drawing combustion air from inside, assuming there is adequate ventilation from outside, ensures that there is always a good flow of air into the boat, which is of course exhausted to the outside. Works very well.
 
I've just installed a heater on my latest boat and although it currently takes air from the ventilated void it's mounted in I'm planning to cut another hole to connect the feed directly to an inlet in the cockpit.

Better to heat cold air to help dehumidify the boat so I understand. Less bothered about fast heat up. We did this on our last boat and it made a difference.
 
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When I fitted mine I ducted the circulating air from the cockpit. The combustion air is drawn from a void which in turn is vented to the cockpit. I was advised this is best for fresh air/less condensation, although it is taking in colder air than if it was recirculating. I suppose the optimum is to draw the cold air through a heat exchanger warmed by the cabin air, but that would create a cold spot in the cabin. That sounds way too much effort for marginal gain so I won't be bothering!
 
jasperthedog said:
For those that are taking fresh air from the cockpit, do you have a picture or link of the inlet vent.
Just curious to know how to stop water getting in.
Click to expand...
My boat is a motor cruiser so the cockpit isn't particularly wet compared to a racing yacht, but I do get plenty of water sloshing about in mucky weather. My vent is covered by a simple cheap plastic louvre but it sits inside a cockpit locker/bin which has an open "grab hole" so it is well protected from splash and has good airflow.
 
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