The minefield of diesel water heaters

[Wardy]

It's been decided that we will buy a diesel water heater, plumb it through four fan assisted matrices for cabin heating and into the calorifier to heat the domestic hot water. But, heres the rub... We get so much conflicting information about which type of H/W diesel heater! Should it be Webasto, Eberspacher tor Mikuni?
When the outlay is more than a grand, i expect to be able to find information that will provide me with an informed opinion of which is best for us, but the internet doesn't help much.
Which is easiest to install, use and maintain?
Which provides the best value for money, is quietest and easiest to use?
I am trying to get an output of about 5kW total, heating the fore cabin, aft cabin, saloon and wheelhouse of a 28'6" Colvic Watson... which system matches my needs most accurately?

I know this has been done to death before, but products change (sometimes for the better!) and the search engine on this site is such a pain to use.

Any advice?


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[[2574]]

I fitted a webasto diesel water heater to my last boat. It is a good heater providing piping hot water very quickly - great for the calorifier. But for heating I couldn't get warm enough air out of the fan matrices to compete with the warm air heaters. The pipework to the matrix was hot - so the problem was getting an efficient enough heat exchanger. I think that there are better units available now than there was when I set mine up. I recall a firm at the boat show 2003 producing the matrix like a mini car radiator rather then simply running a dozen or so copper pipes in front of a fan (like mine were). If you want details let me know and I'll bring the file back from the boat this coming weekend.

rob

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[Becky]

I fitted a Webasto heater, with the plumbing and the fan assisted radiators. Sold the boat soon afterwards, but I understand that the new owners have had some very warm comfortable sailing. I found the installation very easy, at least to plan out. The plumbing took all my strength to bend the (plastic) pipes, but it was supplied by Keto's Toby Hague who was extremely helpful, and it worked brilliantly immediately afterwards.

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[ean_p]

I'd be interested in those details please Rob.

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[heerenleed]

they are all toys

and wont cope wioth any serious use.

We had a Webasto, it broke down after a week of permanent use in its first year. Bu we have heard others having the same problems with Ebersprächers and Mikunis. A liveaboard couple I know fitted two mikunis in case one broke down. Just as well they did, they need them both.

Finally we fitted a Kabola, which is serious business. Also serious priceing, for that matter. And heavy And bulky. But at least we live aboard in comfort.

If you use your heater occasionally, either of them might do. But it still is lottery business. It's not the question if they break down, but when ......

Good Luck (and do consider a diesel heater Dickinson style, fool proof....

cheers and warm winters......

<hr width=100% size=1>Peter a/b SV Heerenleed, Steenbergen, Netherlands
<A target="_blank" HREF=http://www.heerenleed.tk>http://www.heerenleed.tk</A>

 

[aitchw]

Why doesn't anybody use their inboard diesel in the same way as total energy packages do? That is, use the heat from the engine cooling system and exhaust to distribute hot water and hot air around and use the the electrical power to drive lights and other electrical devices. I ask in all innocense as I do not have a big enough boat to test the idea on, though I would if I had. Land based total energy packages claim very high efficiency in energy recovery and I doubt the engine would need to run much above tick over and not at all some of the time.

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[squidge]

Why dont you use radiators for the cabins and a rad and fan for the saloon and wheel house.This would reduce electricity consumption?
I intend to install mine this winter as i now have 99% of the parts required and am thinking of using the "easy fit" plastic plumming pipe and the smallest rads i can find ( 300mm x 300mm ) for the cabins and larger ones + fan & matrix for the saloon.

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[JerryHawkins]

Regular servicing is the answer!

I've had my Eberspacher Airtronic D2 for nearly 3 years and its now run for over 6000 hours. It hasn't broken yet. It has had problems and has failed to start a few times but this was because it needed a service as it was "coked up". Like any "oil burner" it will leave deposits which build up and stop the flame burning cleanly. I serviced mine; it took under two hours (including time to remove and refit) and was very easy following the pictures in the manual which can be downloadde from http://www.espar.com (USA web site). I plan to fit a Hydronic D4 or 5 to my next boat so that I can heat a calorifier and radiators (and/or fan matrix blowers).

I am happy with my Eberspacher and would recommend them as a company. Information and parts are available and although parts are quite expensive, I haven't needed many.

Cheers,

Jerry

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[rex]

Re: Regular servicing is the answer!

My boat had an Ebespacher on when I bought it secondhand and I have had no problems in the 6 seasons I have used it. Only part time granted but I notice the supply is taken from the output of the engine fuel filter. Maybe clean fuel is part of the answer? It has never been serviced but I think I will have a go myself using info from the web site you gave as it smokes on start up now. Is this likely to be cured by a "de-coke"?

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[[2574]]

I'll make a note of the details when I'm down at the boat at the weekend and then let you know.

Rob

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[JerryHawkins]

Re: Regular servicing is the answer!

Quite likely. Its the "swirl" fins on the back of the combustion chamber that get coked up and cause the flame to be mis-shaped. I think this causes a "dirty" flame and hence some additional smoke. You'll see from the manual; but make sure you get the following parts before you start: Both gaskets, glow pin screen and glow pin (expensive and may not need it now, but you get the tool with it that allows removal!). There is also a very tiny filter in the input side of the fuel metering pump - get a new one. A small stiff-bristle tooth brush and "smokers pipe cleaners" are very usefull to assist the cleaning process.

Cheers, Jerry

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[[2574]]

Sorry for the long delay - but these are the folk who can provide the mega efficient heat exchangers. pm'd this to you as well.

rgds

rob

http://www.ketogroup.com/

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[pvb]

It certainly is a minefield, and a difficult decision. You don't say whether you're going to live aboard or use the boat occasionally - and this should be a factor in deciding which system to fit. You're looking at 5kW output, which is about 17000 Btu/hr, and this is the sort of output you'd get from an Eberspacher Hydronic 5. Hydronic systems can work very well and, as you've said, they have the additional benefit of supplying domestic hot water. But they are more suited to providing continuous ongoing background warmth, rather than being able to heat up say the saloon very quickly. The reason is that the fan-assisted radiators each have only a fairly small heat output - perhaps 5000 Btu/hr. In contrast, with an equivalent hot air system, you could close off unwanted vents and push the full 17000 Btu/hr into your saloon to warm it up quickly when you arrive at the boat on a cold evening.

Another consideration is power consumption. Each of the fan-assisted radiators will draw current in addition to the main heater. Depending on what type of fan-assisted rads you fit, you could easily find that the total electrical demand is considerably more than an equivalent hot air system. Obviously, that's not important if you have shore power available, but then in that case you can use an immersion heater to give you domestic hot water.

Installation of a hydronic system is a major job, and you shouldn't underestimate the work involved. It'll take 3 or 4 times as long as fitting an equivalent hot air system. It also needs to be planned and fitted very carefully if it's ever to work properly - a system which allows airlocks to form will be problematical.

In terms of reliability, it's my firm view that correct installation is the key to long-term reliability - whatever the make or type of heater. If you search the interweb, you'll find horror stories of dissatisfied owners of every make of heater.

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[pvb]

300x300 rads...

Be careful to check the heat output before you buy rads. 300x300 rads are typically only capable of putting out about 500 Btu/hr - that's about 150 watts. One of those won't get a cabin very warm!

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