Webasto or Eberspacher wet heating?

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runningman

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I've pretty much decided on installing a wet heating system as it's easier to run small pipes to radiators than it is to cut whacking great holes for blown air heating trunking. I think 5KW output should be enough for our needs (might install a second unit in the other hull at some point but don't want to encourage guests at the moment :D ). Webasto and Eberspacher do similar units and they are both similarly priced (oh what a coincidence!) so which one would you choose and why?
 
runningman said:
I've pretty much decided on installing a wet heating system as it's easier to run small pipes to radiators than it is to cut whacking great holes for blown air heating trunking. I think 5KW output should be enough for our needs (might install a second unit in the other hull at some point but don't want to encourage guests at the moment :D ). Webasto and Eberspacher do similar units and they are both similarly priced (oh what a coincidence!) so which one would you choose and why?
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I'd suggest that ease of installation shouldn't be the criterion for deciding which type of heating to fit. The effectiveness and immediacy of blown air heating is superb. Radiators are of limited efficiency, and matrix heaters demand additional electrical power. So I'd go for blown air, and frankly there's little to choose between Webasto and Eberspacher.
 
True knowlege is the product of direct experience.

I fitted a Webasto Thermotop to a previous boat.

Installation was straightfoward, using plastic 15mm snap together tubing and connectors. No leaks at all.
Heated towel rails in galley and heads, long narrow radiator under the settee berth.

It was terrific-25 minutes and you were taking sweaters off in December.

The main advantage over blown air is a tank of hot water in the same timescale-blown air dont do that!
 
I have had an Eberspacher hot water system in my boat for 15 years. Blooming marvellous. Hot water, hot radiators in ten minutes. Dry clothes, dry towels. Wonderful. Very little noise, no fans.
 
I have a Webasto Air Top and it works OK, but the airflow (even if I close all the other vents) to the forecabin is weak, and the heat losses from the huge surface area of the flexible hoses is very significant. Although I have insulated all my air delivery hose, it still radiates where I dont want it in lockers and along the hull.
Also, the thing drags air from outside of the hull so has to heat the air through a higher temperature differential before passing it to the (total loss) delivery system,

My preference, though I cant afford it, would be to go with the water heated version. The surface area of the pipes is small, and the recirculated water heat is not a total loss.
 
Some of the blowers do use a lot of current.
When I started out bodging a system about 15 years ago, I got the heater out of a small peugeot from a breaker's yard. On full chat, the fan takes about 14 Amps IIRC!
Things have moved on since then.
There are also a lot more effective aluminium 'radiators' about which don't need a fan at all.
On some boats, you need to think about the weight of rads and water.
Being able to get heat to the fore cabin with carving big holes is a definite plus.
Hot water is a real winner.
On my system, I let the eber heat the engine, it worked as a storge heater, slowly releasing its heat to the boat overnight.

Hot air is still good for fast direct heating. If I was designing a boat, I'd want the ducting in the plans from the start.
 
Thanks. For the reasons given, I'm definitely going down the wet system route. Out of interest, to those who have wet systems, did you use normal steel domestic radiators?

...I still don't know whether to go with Webasto or Eberspacher. What about reliability, ease of servicing, cost of replacement parts, etc? Is there anything to choose between them?
 
Reliability is mostly about quality of installation IMHO.
Systems which 'short cycle' due to not enough water flow, or generate overheat errors because air gets in the system, or start-up failures due to air in the fuel, or get switched off at the main supply before the cool-down cycle is complete or trying to run on 11.9 Volts.... etc etc these are the 'unreliable' ones. IMHO.
 
OK, yes, I understand about installation and operation issues, but all else being equal, which wet system 'boiler' would you choose, Webasto or Eberspacher, and why? Help me decide!
 
I have an Eber Hydronic 5 linked to 2 x 2kw fan matrix units (saloon and wheel house), 1 x domestic towel rad in the heads and 1 x small domestic double rad in the fwd cabin. Don't use it to heat a calorifier - we have an instant gas water heater for that function. Eber and webby probably very similar in terms of reliablity and servicing needs. One thing I would say - have a seperate tank for white diesel and run it on that. I had to 'decoke' annually using red, with white I'm in my 4th year with no issues (touch wood!).
 
runningman said:
OK, yes, I understand about installation and operation issues, but all else being equal, which wet system 'boiler' would you choose, Webasto or Eberspacher, and why? Help me decide!
Click to expand...

Those two dominate the market and you are unlikely to go wrong with either. Others cannot make the decision for you. The success of the system is more likely to depend on the distribution part rather than the heater itself, although the person who is going to install the (blown air) system on my boat is a fan of Webasto as he claims it is easier to service.

Just plump for one or the other based on price and how closely it meets your performance requirements and follow the installation instructions to the letter and you can't go wrong.
 
I used standard household radiators which have been fine although a couple of them are now rusting and will have to be replaced. I used plastic tubing between each radiator.
Initially I had lots of problems at the time of installation because I tried to include the engine cooling system in the loop. It turned out to be a bad idea and after I disconnected it everything went well. My Eberspacher Hydronic has been totally reliable and I would recommend it. Don't forget a header tank for the radiator system, very important.
 
Thanks all.

Out of interest, how long did the domestic radiators last before starting to rust? Yes, plastic tubing will be used for the install. I used this for the first time a couple of years ago on a house project - really quick and easy to work with. I would never go back to copper unless I had to. I am not planning to include the engine(s) in the heating system and going by your experience it looks like that's a good thing.
 
I shall be removing a Webasto Thermotop over the winter, no idea what size it is at but can surely find the info somewhere. It runs 1 small rad, 3 fan units, supplies hot water and works faultlessly. Please pm me if interested.
 
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