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Diesel air heater


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3 hours ago, Jen-in-Wellies said:

You could use the cigar instead of a glow plug.

 

Glow plug is fine, measures 0.6 Ohms which seems about right. 

 

Inside of the thing is lightly sooted but no more than I would expect. The swirly bit when the fuel and air mix is a bit more clagged up than I would expect so I'm now inclined to suspect the nasty loud crackling noises it made in the minute or so before going out and packing up must of bin the electronics. Dammit! 

 

Will clean it up properly and bench test it over the next day or three.

 

 

 

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9 minutes ago, rusty69 said:

Has anyone fitted their chinese diesel heater with an exhaust gas heat exchanger  to heat water in a calorifier? 

 

Have you calculated the amount of heat (not temperature) in the exhaust gasses? I am not saying it won't work but I have my doubts and would also be concerned about the exhaust and heat exchanger never getting hot enough to evaporate off the condensation formed with cold surfaces. I suspect it would not turn not to be worth the effort.

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2 minutes ago, Tony Brooks said:

 

Have you calculated the amount of heat (not temperature) in the exhaust gasses? I am not saying it won't work but I have my doubts and would also be concerned about the exhaust and heat exchanger never getting hot enough to evaporate off the condensation formed with cold surfaces. I suspect it would not turn not to be worth the effort.

No, I have done no calculations. I think the exhaust length and angle of exit probably have a significant impact on the amount of condensation that could be collected in the exhaust of these units. I'm not even sure how a connection would be made, or whether the boat safety examiner would like it. I suspect, like you , it may be lots of effort for little gain. Easier to ask if someone else has done it before going to the trouble.

This is the type of thing I was thinking of:

 

https://www.ebay.co.uk/itm/263006556550?_

 

How would I calculate the amount of heat in the exhaust gas, and then translate that into its ability to heat water?

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The exhaust temperatures certainly get very hot, but as Tony says, not sure about the total heat energy. You can get combined air/water heaters, so might be worth looking at one of those (or at least seeing how they do it). I'd be worried about over cooling the exhaust. 

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Interesting link. I suspect Tony is on the right track though. I think they will cool the exhaust gas enough to cause the water vapour to condense into liquid, quite a lot of it, which you'll need to figure out how to handle. I suspect this might be why they are on ebay and not widely sold by Webasto et al. 

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On 23/11/2022 at 11:33, MtB said:

Interesting link. I suspect Tony is on the right track though. I think they will cool the exhaust gas enough to cause the water vapour to condense into liquid, quite a lot of it, which you'll need to figure out how to handle. I suspect this might be why they are on ebay and not widely sold by Webasto et al. 

Liquid condensate might be quite corrosive too. That could rot the exhaust pipework and cut a channel down your hull side below the outlet.

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25 minutes ago, David Mack said:

Liquid condensate might be quite corrosive too. That could rot the exhaust pipework and cut a channel down your hull side below the outlet.

 

A vety good point. On gas boilers the condensate is really quite aggressive although I dunno about oil boiler condensate. The first gas condensing boiler I ever encountered out there in the wild ('on the district' as old skool gas bods call it) was leaking badly when running, and I was called out to fix it. It was only a week old according to the customer and installed by a bunch of cowboys who would not return to fix their dodgy workmanship. 

 

The problem was they had ignored the installation instructions and piped up the condensate drain in copper tube. In just one week it had corroded right through and resembled the sparge pipe in a gents' urinal. 

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1 minute ago, Tony Brooks said:

Judging by the time diesel car exhaust now last I suspect the condensate is a lot less acidic than it used to be with high sulphur diesel. However, I am not sure if the nitrogen in the air will not react to form nitric acid - input from chemists please!



Paging @Dr Bob. Come in please .

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On 22/11/2022 at 16:27, MtB said:

 

Glow plug is fine, measures 0.6 Ohms which seems about right. 

 

Inside of the thing is lightly sooted but no more than I would expect. The swirly bit when the fuel and air mix is a bit more clagged up than I would expect so I'm now inclined to suspect the nasty loud crackling noises it made in the minute or so before going out and packing up must of bin the electronics. Dammit! 

 

Will clean it up properly and bench test it over the next day or three.

 

 

Right, an update. Cleaning up the burner tube is not possible. Once clagged up, it has to be binned and a new tube fitted as there is a diffusion gauze tucked away inside where you simply cannot get at it, or even see it. I think this is the problem with mine. This helpful youtube chap has busted the myth about burning off the clag and cut one ope so you can see what's inside. 

 

https://www.youtube.com/watch?v=llre0dedDZk&ab_channel=DIYHelper

 

So once one of these heaters starts failing to light and the glow plug is found to be good, I reckon a new burner tube is the fix. I've ordered one on ebay.

 

In the meantime the whole new diesel heater (£100) has arrived and superficially it looks identical but on closer inspection one helluvalot of development has taken place since I bought the failed one about two years ago. Every single component I inspect and compare is different in some way or another. So buying a new heater to dismantle for spares is not actually that great an idea. The only bit that looks the same is the user controller and even that probably has completely different software. The PCB inside the heater is totally different.

 

Edited by MtB
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6 minutes ago, MtB said:

 

Right, an update. Cleaning up the burner tube is not possible. Once clagged up, it has to be binned and a new tube fitted as there is a diffusion gauze tucked away inside where you simply cannot get at it, or even see it. I think this is the problem with mine. This helpful youtube chap has busted the myth about burning off the clag and cut one ope so you can see what's inside. 

 

https://www.youtube.com/watch?v=llre0dedDZk&ab_channel=DIYHelper

 

So once one of these heaters starts failing to light and the glow plug is found to be good, I reckon a new burner tube is the fix. I've ordered one on ebay.

 

In the meantime the whole new diesel heater (£100) has arrived and superficially it looks identical but on closer inspection one helluvalot of development has taken place since I bought the failed one about two years ago. Every single component I inspect and compare is different in some way or another. So buying a new heater to dismantle for spares is not actually that great an idea. The only bit that looks the same is the user controller and even that probably has completely different software. The PCB inside the heater is totally different.

 

Do you mean this type of thing? If so, they can be removed with a coach bolt of the correct size. At least, mine could. 

s-l500.jpg

8 minutes ago, MtB said:

In the meantime the whole new diesel heater (£100) has arrived and superficially it looks identical but on closer inspection one helluvalot of development has taken place since I bought the failed one about two years ago

Ah, I see the problem. You bought a failed one, when you should have got a working one.

 

Is the new one bluetooth compatible? It seems the next logical step to get rid of the remote control

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55 minutes ago, rusty69 said:

Do you mean this type of thing? If so, they can be removed with a coach bolt of the correct size. At least, mine could. 

s-l500.jpg

Ah, I see the problem. You bought a failed one, when you should have got a working one.

 

Is the new one bluetooth compatible? It seems the next logical step to get rid of the remote control

 

 

No not that gauze, thats easy to get out. There is another far larger diffuser gauze inside the thing, buried out of sight. Watch the video where he shows it to you in the burner when cut open. 

 

 

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3 minutes ago, MtB said:

 

 

No not that gauze, thats easy to get out. There is another far larger diffuser gauze inside the thing, buried out of sight. Watch the video where he shows it to you in the burner when cut open. 

 

 

Ok. I'll watch it after the Thames series, and after Nicks thing, and after...... 

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1 hour ago, MtB said:

 

 

No not that gauze, thats easy to get out. There is another far larger diffuser gauze inside the thing, buried out of sight. Watch the video where he shows it to you in the burner when cut open. 

 

 

Ok. so I watched most of it. It looks like once the larger diffuser thing is clogged, its a hell of a job to unclog it. Looks also like there are no reliable solvents that will break down the carbon build up. 

 

How about running a tank of kerosene through the burner once in a while? Would that burn hotter and kill the carbon before it builds up?

Edited by rusty69
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1 minute ago, rusty69 said:

Ok. so I watched most of it. It looks like once the larger diffuser thing is clogged, its a hell of a job to unclog it. Looks also like there are no reliable sovents that will break down the carbon build up. 

 

How about running a tank of kerosene through the burner once in a while? Would that burn hotter and kill the carbon before it builds up?

 

CBA. I'm just gonna buy a new burner every few years when it does it. They are only £25...!

 

The thing about carbon is, its highly resistant to heat! 

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Ok another update.

 

I've discovered the fault with my air heater. It wasn't soot build-up. I've been totally wrong-footed and feel like the complete idiot I obviously am. 

 

As usual with a fault, all the evidence was there but I failed to see how it all fitted all together and how I could have sussed it in 30 seconds had I thought about it properly. Here's how the failure developed.

 

At first, the heater became difficult to start. Popped and banged a bit, loads of white smoke from the exhaust. But it eventually it would light and the smoke would clear, sometimes after a re-start.  Then the other day it was running fairly well and I was actually right next to it when it started making some muffled 'crackling' noises like a circuit board frying, then it went out whilst actually running. Would not re-restart at all. Still clouds of white from the exhaust when failing to start. 

 

There yer go. All the information needed to suss out the fault. Any takers?! ;)

 

 

 

 

 

 

 

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