Autoterm vs Eberbasto

Phil_boat said:
Going to go for an Autoterm then I think... I'll get it ordered and have a play around to find the best position for it.

Unfortunately the best position to get heat into the boat isn't the best for getting the exhaust out!

What's the usual way to run the air intake (NOT the combustion air) - take it from inside the cabin so it recirculates or from where the heater is located? Which on my boat is effectively the bilge, although it's a clean bilge being an outboard boat.
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Depends on whether you want to recirculate damp smelly air from inside the boat or, introduce fresh air at positive pressure to drive the damp smelly air out. My inlet is in cockpit locker.
 
Phil_boat said:
Unfortunately the best position to get heat into the boat isn't the best for getting the exhaust out!

What's the usual way to run the air intake (NOT the combustion air) - take it from inside the cabin so it recirculates or from where the heater is located? Which on my boat is effectively the bilge, although it's a clean bilge being an outboard boat.
Click to expand...
What a great question! On my boat, the heater is in the 'engine compartment', albeit that there's no engine, as it's adjacent to the cabin. The heater takes air from the aft locker for the burner, and air from the cabin to heat through the heater and expel into the cabin again; warm air being reheated. TBH, it hadn't really occurred to me the idea of having the warm air intake anywhere else. To have it in the same compartment as the burner, or indeed anything that carried exhaust gas is madness. On the other hand, with as small a boat as a GK24, trying to find a "good" place isn't easy.
 
As Graham376 indicates, if you take the heating air intake from the cabin (or other heated spaces) you will be recirculationg damp air, and the humidity inside will gradually increase from your breathing, sweating, damp/wet clothing, cooking, any gas burning, or leaks or rain getting into the boat.

This seems to me defeat a lot of the point of having heating. On the other hand, it will take less diesel to heat the air inside the boat to the same temperature, though you will probably need the temperature inside slightly higher to achieve the same comfort as humid air feels chillier at lower temperatures (though also muggy at higher ones).

Heating fresh air from outside the boat will be more comfortable; help keep the cabin smelling fresh, dry out clothing and furnishings; help keep mildew and other mould at bay; and help dry out any moisture that collects from condensation and leaks/spillages.

A bit more diesel seems a small price to pay for those advantages, and that's the way I have it. My heater is under the aft deck, which is partially enclosed but sufficiently open to the air via the cockpit.

In my installation, the combustion air intake is also nearby in the same place (under aft deck) as the heating air intake, and this seems compliant with the instructions, and has also proved satisfactory with the decades old Eber installation now being replaced. The heating air must not be intaken from anywhere where exhaust fumes could be present (whether heater exhaust, or propulsion engine or generator exhausts).
 
Phil_boat said:
!

What's the usual way to run the air intake (NOT the combustion air) - take it from inside the cabin so it recirculates or from where the heater is located? Which on my boat is effectively the bilge, although it's a clean bilge being an outboard boat.
Click to expand...
I take my intake air from outside, ensures minimal condensation in the heated cabin.
 
jamie N said:
To have it in the same compartment as the burner, or indeed anything that carried exhaust gas is madness.
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There really is no reason the heater air intake (and the combustion intake) cannot be from the same compartment that the heater itself is in.

If you’ve got an exhaust leak you have a massive problem regardless of where the air is taken from.
 
jakew009 said:
There really is no reason the heater air intake (and the combustion intake) cannot be from the same compartment that the heater itself is in.

If you’ve got an exhaust leak you have a massive problem regardless of where the air is taken from.
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That's how mine is arranged (as installed by the reputable builder). It means that we're not having to heat freezing cold air. Drawing the combustion air from inside ensures that that volume of air is drawn into the cabin from outside, giving guaranteed ventilation.
 
The EU regs for the installation of these heaters in vehicles prohibits the hot air intake being capable of being contaminated by exhaust fumes from the heater itself, or from the engine. Assume similar for boats. So it’s wrong to install such that hot air intake is in the same compartment as the heater, and also cannot be drawn from the engine room assuming the heater is not in the engine room; mine’s in the lazarette but draws hot air from the cabin. Needs eg to be from outside, or from cabin.
 
jakew009 said:
There really is no reason the heater air intake (and the combustion intake) cannot be from the same compartment that the heater itself is in.

If you’ve got an exhaust leak you have a massive problem regardless of where the air is taken from.
Click to expand...
Unless you want to die. Regs prohibit this. Arranging the installation such that sucking in exhaust fumes and warming them up to inject into your cabin is feasible, is utterly stupid.
 
jamie N said:
I replaced the Eber D5(?) with a Chinese item, and like many, had no real problems as it fitted well enough. The exhaust I renewed and lagged with exhaust wrap stuff, which was suitable from an auto factor, and all seemed well. However, after having not used it for a few months, when I fired up the heater, it came on without issue, but the cabin became 'smoky'. Obviously I shut it down, and thought the worst of it all, however the 'smoke' hadn't smelt of anything, and the air analyser in the cabin hadn't issued a warning, or indeed noted any significant change in the atosphere apart from it getting warmer; odd?
The 'smoke' was steam from the lagging, which had taken on the moisture during the period of inactivity, as well as being a known effect from exhaust wraps or lagging, which will often smoke and smell for the first few heat cycles as any manufacturing oils or residues burn off.
As a check though, I removed the lagging, and ran the heater 'naked' as it were, and saw that there weren't any defects, and so refitted the lagging knowing that it wasn't going to kill me.
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I'm quoting myself here, as I didn't fully explain the situation. I reread my original post, and saw that it didn't make sense, because it doesn't explain how the 'smoke/steam' entered the cabin.
The lagging is on the exhaust pipe, which is in the 'engine bay'. The warm air inlet comes from the cabin, so how would the cabin become smoky?
Simple, the warm air intake hose fell off of the heater itself, thus the warm air was coming from a source at the heater in the engine bay'. Fortunately, the exhaust wasn't leaking, or the 'smoke/steam' effect could've been lethal. It was while I was dealing with the lagging that I refitted (properly) the warm air intake hose.
 
Sticky Fingers said:
Unless you want to die. Regs prohibit this. Arranging the installation such that sucking in exhaust fumes and warming them up to inject into your cabin is feasible, is utterly stupid.
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I think we’re going round in circles here so I’m going to bow out.

The fact is that thousands of boats do have the heaters installed from factory with the intake air being drawn from the same compartment as the heater is in.

Eberspacher in their manual literally have a diagram of such an install (without an intake hose) saying that it is fine.

IMG_1328.png
 
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I'm not happy with the Autoterm 'Confort Controller. If I use POWER mode the heat output at max is fine. Use it in Temperature mode ie set to increase from where you are to where you want to be, and it doesn't try half as hard. I would expect it to go flat out then taper off as it gets there. It doesn't seem to do that, just dawdle along so it takes forever. I asked them about microcode updates and temp curves but they just wanted pictures of my installation.
 
"The exhaust gases being pumped directly into the cabin."
OK, do a risk assessment on the possibility of that, which is: Is it safer to have the warm/fresh air inlet in a separate location from the exhaust, or alongside the exhaust?
With having the air inlet apart from the exhaust, it would then require 2 mainifolds to leak; the exhaust to let that gas out, and the air inlet to allow the exhaust gas in.
If the air inlet is from the area of the exhaust, it only requires a single mainfold to leak.
Not a tricky conundrum is it?
Imagine a court of inquiry and putting that forward as "best practice"...... 🤡
 
Sticky Fingers said:
Not really, as I don’t sleep in the boat with the engines running….
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You don't need to be asleep to die of carbon monoxide poisoning. You could be underway, you could be cooking on the gas stove or you could be sitting watching the TV with the heater on. You could be sitting around in a boat with no heater, no gas and no engine running and still dies from Co poisening, caused by an adjacent boat running his engine, using a faulty heater, running a generator etc etc.

The correct way to avoid Co poisoning is to fit a Co alarm..
 
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