That Johnny

Ah yes, it's a fancy Sterling one, no voltage drop. Pro Split R, it's called.

Ahahaha, you are zeroing in on a forthcoming bodge! Surely a sixth sense you've developed OK, caught red-handed... I am cheapskating a bit while prototyping this. I use a toggle switch to turn on/off the main split-charge diode for the battery banks, without the diode being on the engine can't start. The switch just connects the starter battery to the diode. As I am currently in the early stages of tinkering with this heater idea - and not moving anywhere in the foreseeable - I am using the same switch with one lead taken off and replaced with a lead going to a little relay which, when energised, puts the starter battery positive voltage on the end of a nice thick wire which can supply the Eber with its power via the appropriately-sized fuse. Once built and tested I'll get a proper electrical isolator for the Eber and probably run it off the domestic battery instead of the starter.

It would fit in the space betwixt uxter plate and stern deck with the drain elbow and brass winding attached, however, I'd have to raise it all by 15-ish centimetres. I've got a nice little stainless bracket it will sit on, that mounts to the uxter plate, and extending that by 15cm vertically would be fiddly/annoying. There's enough vertical space but it'll be much better/neater not to go that route...

The heater will be underneath the stern deck, on the uxter plate as Tony correctly surmised, near the weedhatch. There's a lot of air around it, and water below it; the ambient temperature in that area on a standard winter morning is low single-digit celsius. I'm hopeful that (if I use the drain) the loop water won't evaporate in use - that is a perceptive point! - I am actually wiring this so that it is not possible to use it when the engine ignition is in use, as that would be the major source of heat in the engine compartment. Still, even when chugging along at ~1krpm to charge batteries in winter, the engine room only enters the low 20s of degrees celsius.

Thanks, very useful... ta!

For illustration purposes here is an image from another forum showing an installation where the air heater has run without the bowl/tray etc underneath the condensate u-bend exit. That brass pipe is way longer than the one I have but you can see the problem - the whole thing has to go upwards to accomodate...

Cheers David Mack! My hope is that I'll be convinced it isn't necessary. Because then I won't have to faff about raising the mounting bracket and rerouting the exhaust and making/installing the drip tank/tray for the brass pipe to piddle into!

Aha, cheers. I don't intend to use a skin fitting, I was just going to have an open-topped tank ~1 litre capacity which the brass pipe would drip into. Visual inspection every morning at same time as turning heater on, suction pump out into a jam jar if/when needed. In event of overflow, water route would be into aft bilge, where water sensors and automatic pumps are fitted.

Standard enough practice that Eberspacher specifically manufacture the parts for it. Standard enough practice that on other forums I've already looked at, one finds posts such as the attached. Standard enough that there are multiple companies based in the UK selling the parts specifically for marine applications. Standard enough practice that there are a bunch of videos on Youtube about it. Cool, thanks matty40s!

Ciao

I've never fitted one, dunno where you get that "imply" from. I'm specifically asking for advice and you're being a prickly pear. Not sure what bit of "it's a u-bend filled with water" you don't get? You'd actually have saved yourself a bunch of time (and everyone else who reads this thread) by just clicking the link I provided so you know what part I'm talking about. Oh Well! Coz I woz hopin dat on dis forum about boat stuff someone would know Is the exhaust hull fitting the lowest part of the system? Is the heater exhaust outlet the highest point of the system? If either of these are answered in the negative, what do you believe happens to condensation that forms in the exhaust pipe?

Yep, I agree... as in, this is my presumption too. The aft of the engine compartment on a permanently-moored boat in winter can be chilly, however; the D4 will be in a cold and damp environment (like so many, I have rain water ingress issues to solve). The original question I asked was exactly: is this really the case? Specifically, is 1200 mm a safely-short-enough distance that a yearly visual check on the condition of the exhaust pipe will pre-empt the formation of any leaks in the absence of a condensate drain?

I specifically asked for opinions from people with experience in installing these drain fittings The "answers" I was given here were not to the question I actually asked. I already *did* searched the forum, hence asking the question here. A bit of "not presuming you're talking to an imbecile" would be nice - I work as a technician designing and building equipment for scientific research. I explained what I was after clearly and now look, the thread has got nasty(ish) - would it maybe be better to double-check the OP's posts and then ask clarifying questions rather than immediately saying I'd bought the wrong parts?

I get a bit annoyed at posters who presume the OP has no basic competence and don't read the posts they're replying to properly, LOL The Eberspacher Airtonic D4 is sold for both marine and automotive applications The parts I linked to are specifically for marine applications, clicking the link would have revealed this. Condensation is more of aproblem in marine environments due to the wet nature of the water surrounding the boat.

Hmm... if you look in Eberspacher's official accessories brochure, in the "exhaust system" section starting page 110, the part numbers for a 24 mm i.d. 90 degree exhaust elbow with condensate drain hole, and the associated brass winding, are 251226894500 and 25847160200 respectively.