Hot air heating

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Hot air heating

Postby Chris » Mon Sep 01, 2014 9:10 pm

Hi everyone, hope you have all been having some fine sailing.

I've been busy doing some more upgrading over the last couple of weeks with a cockpit shower (hot and cold pressurised water) and a new Webasto hot air heating system. I do like my creature comforts!

I am part way through the project and having decided to install the heater unit in the starboard cockpit locker, fairly well aft and up out of the way, I am just wondering if anyone can confirm the position of the exhaust outlet. I am intending to position it just below the teak rail on the transom, towards the centre line away from the two existing air vents.

The 60mm hot air ducting runs through the bulkhead between the cockpit locker and the saloon, in behind the starboard cupboard/nav table, behind the drawers, down to the lowest cupboard below the drawers and through underneath the starboard berth. It exits with a flush, adjustable vent between the two cupboards, blowing out into the middle of the saloon. From there and if required a further branch could be taken past the heads and into the forepeak but I don't think that will be necessary.

Antti, I seem to remember seeing you have a Webasto unit, I would be interested in knowing how your system is installed.

I will post some pics as the projects nears completion.

All the best

Chris

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Re: Hot air heating

Postby Antti_DD » Tue Sep 02, 2014 6:21 pm

Hi Chris, nice to hear from you!

Looking forward to seeing some photos of the cockpit shower, as that's something that I would also like to have someday.

Speaking of the Webasto, we have the main unit located also in the starboard cockpit locker. I would like to add caution here, since the exhaust pipe gets, especially near the unit, very hot, which can be dangerous since the locker is often full of various stuff. We almost burned one cockpit pillow since it was located too close to the pipe! Lesson learned, I always check the locker before starting the heater. Adding some insulation might also be a good idea.

We have one vent in the saloon and another one in the heads/forepeak. Our exhaust outlet is also located on the transom and here is another lesson that I learned, since the outlet is placed too close to the side and this part of the transom can be under water when the boat is heeling to starboard. I actually used a wooden plug (see the attached photo) to prevent water entering the heater/exhaust pipe, before a gooseneck was installed to the pipe. Nevertheless, the heater still cannot be used when the boat is heeled to starboard.

Webasto unit.jpg
Webasto unit.jpg (41.56 KiB) Viewed 2833 times

DD_transom.jpg
DD_transom.jpg (80.42 KiB) Viewed 2833 times

DD_transom2.jpg
DD_transom2.jpg (38.05 KiB) Viewed 2833 times
Antti Laine, Forum Administrator
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Re: Hot air heating

Postby Chris » Tue Sep 02, 2014 10:49 pm

Hi Antti, thanks for your speedy and very helpful reply. The photos are very informative.

I do remember you mentioning about the heater mishap and have considered a shield protecting the exhaust area of the heater. I am not exactly sure of how the pipes will run to the outlet as yet but they will all be double insulated.

The outlet on DD does look a little vulnerable when heeled to starboard. I am hoping to position the outlet slightly higher and more toward the centre line.

Is your unit fitted with a silencer? Also is it fed from the main diesel tank or have you a separate tank?

I have mounted the heater unit and pump on a fairly substantial steel plate with anti vibration mounts. The heater on my last boat was mounted beneath the bathing platform and even though she was nudging 40 feet the noise from the heater was quite noticeable even right up in the forward cabin. So I'm hoping this will help reduce any vibration transferring through to the hull.

The cockpit shower was actually quite an easy undertaking. The tricky bit was deciding where to position the unit. In the end I put it just behind the morse control where the pipes don't interfere with anything in the locker and it is virtually flush with a neat little door which you can position vertically, it fits perfectly.

I realise having pressurised hot and cold water makes it all the more possible but during this season there have been many times where I have thought how nice it would have been to have had a cockpit shower to either cool down or freshen up at the end of a busy day sunbathing!

I would think it will be 60 quid well spent.

I will take some pics of it as it is so neat and unobtrusive - the heater too.

Cheers



830596.jpg
Mizar cockpit shower (Force 4 chandlery)
830596.jpg (29.61 KiB) Viewed 2827 times

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Re: Hot air heating

Postby Antti_DD » Wed Sep 03, 2014 1:14 pm

DD's heater is fed from the main diesel tank which is a practical choice since one doesn't have to fill different tanks. However, the heater might be more vulnerable to impurities of the diesel/main tank compared to the engine, but I haven't experienced any problems with this arrangement.

I am not sure what you mean with a silencer, but to my knowledge our Webasto doesn't have one. The ST2000 Air Top does sound a bit like a jet taking off, when it is starting to heat, and the sound can be heard also from the cabin, but I haven't considered this a big problem. I haven't experienced any vibrations when the heater is running.

The Webasto has been very reliable, so I am pleased with the unit. However, the only problem is that the heater only has two modes: on/off. Especially during the night time, it is difficult to get an optimal temperature as it tends to drop when the heater is not running and often the temperature gets first too warm and then too cold. Also the thermostat is located near the nav table, so the temperature is often a bit different in the fore peak.
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Re: Hot air heating

Postby Chris » Wed Sep 03, 2014 3:14 pm

silencer.jpg
webasto silencer
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Here's a picture of the silencer which is quite pricey. But as I was going to the expense and effort I just thought it best to include one at the stage.

To take diesel from the existing tank would mean extracting the tank and then boring a hole in it. Somebody suggested you could take a line from the engine feed by the primary filter and I was going to do this until I read the installation instructions where it says… 'DO NOT USE THE ENGINE FUEL LINE' ! So I will be fitting a separate 10 litre tank.

Take your point about the heating modes but I have to say I think it's the way these heater tend to be.

Thanks for the insight Antti - all valuable info!

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Re: Hot air heating

Postby Mallemuk » Tue Sep 09, 2014 7:37 pm

My original Thermo 2500 heater does not work and so far our gifted car mechanic has not succeded in fixing it. I am very interested in reading about your experiences on the matter before buying a new heater. Any good suggestions on which heater to buy? Could I buy a heater for a car and fit on the boat? They seem to be a bit cheaper.
Kind Regards,
John

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Re: Hot air heating

Postby Antti_DD » Tue Sep 09, 2014 9:34 pm

Hi John, as I mentioned earlier, I have been quite pleased with Webasto ST2000+ (served for four years now). If I remember correctly, I bought a marine installation kit together with the heater, so the actual unit might be the same as used in cars. Not sure of this though. The marine installation kit adds to the costs, but the actual heater might also be more expensive when bought from a marine store. I am sure that Chris has more up to date information on the subject.

p.s. Chris, if you take a look at my first photo "Webasto-unit", is that a silencer or something else? At least the shape of the pipe is similar to your image.
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Re: Hot air heating

Postby Mallemuk » Wed Sep 10, 2014 7:45 pm

Hi Antti
Thank you for your reply. The Webasto looks like a nice heater and I have been looking at different prices. Surprisingly up to 25 % of the price can be saved by checking different offers on the internet-even in a small market like the Danish. Around 1300 Euroes including the kit with fittings and extras.
I have decided to buy and install the heater some time during the autumn or winter after Mallemuk has come out of the water and into her boat shed. I plan to end this season some time in October.
Again, Thank you for advice and a great HR29 Forum.

John

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Re: Hot air heating

Postby Chris » Sat Sep 13, 2014 4:06 pm

Hi John, sorry I have not replied sooner, but I have been at the boat fitting the heating!

The basic units are the same. The predominant market is for trucks and vans. Items are added for a marine installation and both Websato and Eberspacher put kits together for this purpose and then offer a warranty for use in a marine environment. You do pay more for this. It may be a good idea to shop around though.

You can compile a kit yourself but there is a danger the basic unit will not be protected by a warranty. I have been dealing with a UK company who have been very helpful in this regard and I have probably made a reasonable saving on all the components. Certainly in respect of the ducting and ancillary items like vents and lagging.

I am hoping to fire it up at my next visit but as the installation has evolved I have had to make a few journeys to and from the boat, ordering extra bits as things developed.

The reports I have read about the Webasto Air Top 2000ST have been very favourable and being more than adequate to heat our size of vessel.

I will let you know how it goes and will include some pictures of the final installation.

Antti, with regards to the silencer, the shape is what drew my attention to your exhaust ducting. It does appear to be some sort of silencer. Just worried me when you said it sounds like a jet engine when starting up!

Cheers

Chris

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Re: Hot air heating

Postby Antti_DD » Sun Sep 14, 2014 8:58 pm

Chris wrote:Antti, with regards to the silencer, the shape is what drew my attention to your exhaust ducting. It does appear to be some sort of silencer. Just worried me when you said it sounds like a jet engine when starting up!


Yes, I think we might have a silencer. I just ordered the marine installation kit, so maybe it was included in the package. With this jet analogue I was actually referring more to the type of sound and (luckily) not so much to the volume :) When thinking about it, the sound is not actually too loud in the cabin, as the unit is located in the cockpit locker. During the nighttime I can distantly hear from the fore peak when the heater is starting up, but it is not disturbing sleep or anything. In a boat where the heater would be located in the cabin the volume might be a bigger problem.
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