Eberspacher/Webasto etc condensate drain brass winding - opinions for/against?

[David Mack]

I think some of the forum regulars are being unfair to the OP. This is clearly a unit with a sealed silencer and the condensate drain is not just a drain hole, but a properly plumbed in u-bend (actually 4 u-bends in series), as is apparent from the OP's description in an earlier post and from looking at the links in the OP's first post. This will not allow CO to enter the boat interior. 

Personally I can't see anything wrong with the OP's proposal. What I can't say is whether it is necessary.

Edited August 13, 2021 by David Mack

[Alan de Enfield]

8 minutes ago, Tony Brooks said:

 

You will notice that I was careful to specify "a typical canal boat". That is because on other boats it would be easy to fit a thorough hull condensation drain that complies with the standards. If your boat is not a typical canal boat, then tell us what it is and where you intend to fit the heater.

 

 

 

In his opening post he said it is a 52 foot narrowboat.

 

All replies have been based on that fact.

Edited August 13, 2021 by Alan de Enfield

[That Johnny]

8 minutes ago, matty40s said:

The only way that would be safe is on a larger vessel, with the eber fitted higher than waterline, and the condensate tube taken down to an external skin fitting.

On a narrowboat, it is not needed, but if fitted, could possibly be outletted to the skin tank recess.

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.

[Tony Brooks]

2 minutes ago, David Mack said:

I think some of the forum regulars are being unfair to the OP. This is clearly a marine unit and the condensate drain is not just a drain hole in the silencer, but a properly plumbed in u-bend (actually 4 u-bends in series), as is apparent from the OP's description in an earlier post and from looking at the links in the OP's first post. This will not allow CO to enter the boat interior. 

Personally I can't see anything wrong with the OP's proposal. What I can't say is whether it is necessary.

 

Again, considering a typical canal boat:

 

The exhaust exits the bottom of the boiler. If you inverted it and vented from the top, then any condensation is likely to run back into the unit. Now consider how tight under the gunwale you can fit the heater, the depth of the heater and the depth of the exhaust elbow plus the depth of the condensation fitting. The question is will this allow the condensation drain to exit 10" above the waterline or even above the waterline at all.

 

If there is not enough height then the OP could fit the drain with a shut-off valve on its skin fitting, I would suggest doing so with the outlet below the  waterline could introduce more dangers than it solves. Otherwise, he could ignore the standards for skin fittings and height above the waterline.

 

 

[That Johnny]

8 minutes ago, David Mack said:

I think some of the forum regulars are being unfair to the OP. This is clearly a unit with a sealed silencer and the condensate drain is not just a drain hole, but a properly plumbed in u-bend (actually 4 u-bends in series), as is apparent from the OP's description in an earlier post and from looking at the links in the OP's first post. This will not allow CO to enter the boat interior. 

Personally I can't see anything wrong with the OP's proposal. What I can't say is whether it is necessary.

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!

[That Johnny]

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...

Edited August 13, 2021 by That Johnny
mistyped "from" as "form"

[Tony Brooks]

9 minutes ago, That Johnny said:

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...

 

That looks spaciously like a GRP boat, that often have much higher hull sides than a narrowboat. I don't see how that arrangement solves the potential CP problem. GRP cruisers often have bilge blowers that would remove any CO, few narrowboats do, and one would not normally operate bilge blowers when moored up at night.

 

The height thing is what makes fitting the condensation drain on a narrowboat a problem.

[David Mack]

13 minutes ago, Tony Brooks said:

I don't see how that arrangement solves the potential CP problem.

The coil is full of water - initially primed with fresh water and subsequently topped up by condensate. It functions in the same way as a sink u-bend to stop exhaust gases (including CO) from passing through.

 

In the photo the condensate just dribbles onto the grp and presumably down to the bilge. The OP is proposing to provide a container which would need to be emptied periodically. For a steel boat this is better as condensate is corrosive. 

[Tony Brooks]

31 minutes ago, David Mack said:

The coil is full of water - initially primed with fresh water and subsequently topped up by condensate. It functions in the same way as a sink u-bend to stop exhaust gases (including CO) from passing through.

 

In the photo the condensate just dribbles onto the grp and presumably down to the bilge. The OP is proposing to provide a container which would need to be emptied periodically. For a steel boat this is better as condensate is corrosive. 

Thanks, so if the OP can install it then why not. I think he could even cut the lower end off because it's the coil that traps the water/condensate.

[Tracy D'arth]

In every blown diesel fired installation that I have seen in narrow or broad canal boats there has never been a condensate drain of any kind as the exhaust gets so stinking hot that it stays hot long after shut down and condensation is not a problem. Nor have I seen the stainless exhaust flexible pipe corrode to any serious degree.

Working on the KISS principle I would not have a drain at all. The swan neck would prevent rain and canal wave entering the exhaust. 

 

If the proposed 4 loop drain was in the average under floor engine space I would be concerned that the heat in the space would cause all the fluid in the loops to evaporate rendering the drain a hazard due to CO entering the boat.

[Tony Brooks]

12 minutes ago, Tracy D'arth said:

In every blown diesel fired installation that I have seen in narrow or broad canal boats there has never been a condensate drain of any kind as the exhaust gets so stinking hot that it stays hot long after shut down and condensation is not a problem. Nor have I seen the stainless exhaust flexible pipe corrode to any serious degree.

Working on the KISS principle I would not have a drain at all. The swan neck would prevent rain and canal wave entering the exhaust. 

 

If the proposed 4 loop drain was in the average under floor engine space I would be concerned that the heat in the space would cause all the fluid in the loops to evaporate rendering the drain a hazard due to CO entering the boat.

 

And thinking about it, I doubt he would have enough vertical space to install it without bending the pipe, even possibly having to install the coil horizontally because of the width of the uxter plate (assuming as stern installation). That would make it a nonsense.

[That Johnny]

1 hour ago, Tracy D'arth said:

In every blown diesel fired installation that I have seen in narrow or broad canal boats there has never been a condensate drain of any kind as the exhaust gets so stinking hot that it stays hot long after shut down and condensation is not a problem. Nor have I seen the stainless exhaust flexible pipe corrode to any serious degree.

Working on the KISS principle I would not have a drain at all. The swan neck would prevent rain and canal wave entering the exhaust. 

 

If the proposed 4 loop drain was in the average under floor engine space I would be concerned that the heat in the space would cause all the fluid in the loops to evaporate rendering the drain a hazard due to CO entering the boat.

Thanks, very useful... ta!

[That Johnny]

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.

[That Johnny]

1 hour ago, Tony Brooks said:

 

And thinking about it, I doubt he would have enough vertical space to install it without bending the pipe, even possibly having to install the coil horizontally because of the width of the uxter plate (assuming as stern installation). That would make it a nonsense.

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...

[Tony Brooks]

10 minutes ago, That Johnny said:

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.

 

Why would that be a problem as long as you have an adequate supply of fresh air for both lots of combustion - genuine question, I have never worried about it.

[That Johnny]

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.

[Tony Brooks]

I know you did not ask this, but are you aware that a passive spilt charge diode paired with a machine sensed alternator (as most are) is asking for battery problems because of volt drop across the diode. Something like up to 13.7 volts instead of 14.4V.

 

Think about using a VSR for charge splitting, and that will allow any charge source to charge both banks as long as it's properly wired.

[That Johnny]

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