Hydronic heating. cabin/water

[ColdEH]

Hi there , how big is your boat, hull material ? and does it have a pilot house ?

Just found your website, nice boat , you may be needing more then 10000 btu to heat her , again what is the hull made of ? How have you insulated it ? And will you winter on her ?

Regards

[ColdEH]

Sorry my mistake I thought it was a 10000 btu setup but it is 32000 btu , that should do it .

[sobraon]

Thanks for the response Typhoon.

To answer your questions, 'Spirit of Sobraon' is 42' on deck, however due to her heritage and design the internal volume is more equivalent to a much larger boat as can be seen here..

Interior Tour . She was professionally built as an increased sized spray hull replica from plans taken from Ken Slacks 'In the wake of Spray' and Joshua's own plans in 'Sailing Alone'. Hull and decks are very well insulated, over 45mm FRP and foam sandwich. Our only concerns are the cabin top sides, that are FRP over Ply and the port holes and hatches..

She doesn't have a pilot house. It does have a very secure Center Cockpit.



I hope the Hydronic 10 unit is big enough. At 10kw / 33000 btu's I expect so. I have no experience with heating although I have a long engineering background.

I would like to know how well the fan forced 1.7kw heater coils heat a compartment. I have 4 to install. The boat is very well zoned into 3 major compartments. The Fwd Cabin, the Saloon and the Aft cabin. My intention is to have 1 each in the cabins and 2 in the saloon.

We are full time cruisers on a high latitude east about circumnavigation. So yes we will be on the boat during winters.

We are currently sailing in Korea and Japan and will be crossing the North Pacific to Alaska, Canada and the Pacific North West of the US next year.

I will draw a schematic of the system later today and post it on the forum.

Regards

Garry
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[sobraon]

This is the intended layout of our hydronic system. The towel heater and engine heat exchanges will be at added later stage when I source the units..



Garry
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[GILow]

Originally Posted by sobraon

This is the intended layout of our hydronic system. The towel heater and engine heat exchanges will be at added later stage when I source the units..



Garry
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I am not going to let my wife know about the towel rail!

[sobraon]

The secret to having a happy crew.

The towel heater will double to heat the Head and bathroom and make it a drying room as well. We have a laundry on board so we need the drying room.

We have been cruising full time for a long time in some less than sunset and margarita situations. For those who know our story we have had to deal with some pretty testing times. Conveniences make life all that more enjoyable.

Garry
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[ColdEH]

Hi Garry, very nice boat and work you have done. I have designed and installed two complete hydronic systems on my boats , both based on Webasto 2010 units which are 35000 BTU . We split our time on the boat all year around so I know a thing about living on a boat in the winter when the ice is a foot thick outside. First , I see a header tank , which is good but no buffer tank . these heaters do not like to be short cycled , they need to come up to full temperature every time and run for a while or clear out the carbon that is created on startup. If this fails to happen carbon builds up inside the burnertube and exhaust and becomes a maintenance nightmare . So first you need to get yourself a 20 liter tank in line somewhere and have the furnace passing coolant through that as well , the time it takes to heat it will give you unit time to fully come up to temperature. Also , these things have terrible pumps !!! I mean really bad ! Next thing you will want to do is get tear out the pump that comes with the unit and replace it with a better one . You can look back on my posts and see the one i finnaly settled on , and it is amazing . pumps masive amounts of coolant and is wisper quiet. It has to be , it is under my bunk ..Next thing . don't worry about a summer switch , if the fans are not running you will not notice the heat , we never did . and if you shorten the circuit you will be short cycling the unit again, they need mass to run properly . Next. all heaters should be in series , open those up the way you have them plumbed and you will have no flow thru them , you need flow through the core and there are resistant to the flow . If they are in series they will all work together instead of the coolant finding the easiest path through the least resistance. Plus no pump could feed that parallel layout. I did not add any heat exchangers to my engine or generator . It was complicated and I dont run either of them for very long so I kept it very simple . I took out the water heater completely and have the furnace heating the water with a 50 foot copper coil in the buffer tank. So yes i run my furnace year around to heat my water so I know on a 33 degree day I do not notice extra heat in the cabin as long as the fans are off. You really want to keep the system as simple as possible with as few connections as you can to minimize any leaks they may occur .

This system has been running on my boat for 3 years now , no maintenance issues , once a year i change the injector nozzle , thats it . I did change the pump a couple of times until I got the right one and I built two callorifiers the first one was to small.

Regards John

[ColdEH]

And an added note , your header tank has to be at the highest point of the system so it and have an airspace on top of the coolant so the system has space to expand during heatup . It also catches any air that may be in the system as the coolant passes by . These tanks are usually teed of of the main branch are are clear so you can see the level , make sure you leave space above it to add coolant . They are the same as in a car . I actually use one from a BMW , it is plastic and very tall , very easy to see the level . Filling and burping the system when you first get it running is a challenge, I used a wet dry vacuum to draw the coolant through the system and still had a few air locks to deal with , make sure you have a couple of thermal shutdown fusses on hand , you are sure to blow one before you get all the air out . A laser temperature meter helps as well .
This is the pump I used

http://www.ebay.com/itm/Gorman-Rupp-...AAAOSwo3pWeZOW

Regards John

[ColdEH]

A few more thoughts >

The heater cores can heat your cabins no problem , you may have to add a few and adjust the fan size and speed , that is your control point, the fans . You want to remove equal or more heat in BTUs from your system then is created by your furnace other wise heat thermal shut down . You will know by watching you coolant temperatures , if they rise slowly as the full system is running it will top out and turn off the furnace due to high temperature , I personally don't like to run the system that hot . Some will say that it is ok but i like to have control over my coolant temperatures . So i have a thermostat controlling the fans by coolant temperatures not by the furnace thermostat. It is a fine balance you have to find to get it dialed in .

Also , these things are dangerous !!! They will burn your boat down if you do not watch your exhaust runs . VERY HOT!!! Insulate them right and keep it away from any flammable objects like bulkheads and fiberglass , check it every few months to make sure nothing has shifted . You must be vigilant.

Regards

[sobraon]

Thanks for the input John.

The header tank is supplied by eberspächer. It is clear and will be mounted above the unit in a locker above the lazarette.

The expansion tank if needed is a fairly easy thing to add to the system and we have plenty of room in the engine room.

I will have to see how good the eberspächer pump is. Blogs that I have read by those with eberspächer units haven't complained, however if it is a problem I will go with your recommend. Obviously I don't want to trash the system before I have even installed the system.

I Took a Shower! – Two At Sea have a short system and so far they seem happy with it. That was the reasoning for the summer valve.

I am also posting on the other thread to document the install. I will write a blog on our projects page Projects and Maintenance - Blog Summary View



Garry
wwwsobraon.com

[sobraon]

Thanks again John,

I am pretty sure that the thermostats that come with the unit control the fans in each zone via cabin temp. Until it arrives I can't be sure.

The unit will be mounted in a lazarette with a lot of room and air flow. I will watch and keep an eye on the exhaust when I install.

Cheers

Garry
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[Dockhead]

Originally Posted by sobraon

. . . I hope the Hydronic 10 unit is big enough. At 10kw / 33000 btu's I expect so. I have no experience with heating although I have a long engineering background.

I would like to know how well the fan forced 1.7kw heater coils heat a compartment. I have 4 to install. The boat is very well zoned into 3 major compartments. The Fwd Cabin, the Saloon and the Aft cabin. My intention is to have 1 each in the cabins and 2 in the saloon. . . .

I have exactly the same furnace in a rather bigger boat. The system as a whole is not capable of keeping the boat more than 10 or 15C warmer than ambient. But I guess that for your boat it will be enough. My installation is further challenged by a great deal of ventilation -- 8 large dorades, which I am loathe to close off. But pay attention to the fan coils and how the heat flux is rated -- they may not give their rated capacity. 1.7kW sound a bit small to me. Mine are 3.5kW each.


One tip about this furnace, used in remote places:

It is not highly user serviceable, and it is controlled by a computer which will shut it down upon the occurrence of various error codes, not to be restarted without a service harness. Heating becomes a mission critical system at a certain latitude. So you will want to invest in a good set of spares and service harness, and figure out how to service and repair it, or better yet, a complete spare unit. I will have two of them (one larger, and one smaller one) in my next boat, so that redundancy is built in.

Concerning your installation: Mine was part of the original build of my boat, so was installed with thought. It is exactly like what you are proposing to do -- in the lazarette, fed with fresh air from the bilge. The very short pipe run for the exhaust is a safety enhancement, in my opinion. It works fine. My installation has a wooden cover over it, to protect it from things shifting in the laz -- something you might also want to consider.

[witzgall]

The Espar m-ii units are different from the Webasto 20xx series. When turned on, the Webasto brings the water up to temp in the system, and keeps it there unit power is removed. It has one output setting, full. Because of these two points, it needs an expansion tank. The Espar m-ii series has several temp settings. It heat is not called for, the system goes into standby and the water Temps go to room temperature.

Chris

[transmitterdan]

I have one Hydronic 10 in a 42 ft boat. It is adequate at ambient temps down to -10C. The boat is well insulated from rubrail down. Most condensation is at port lights and overhead hatches. Port lights can be remediated by placing plastic sheeting across the external opening thus creating an air gap between the glass and the ambient air. The overhead hatches can be slightly cracked to help remove condensation. But still we get some drops.

Dockhead's advice about spares is valid. A spare control unit and spare fan will cost about 1/2 the amount of a spare furnace unit. Mine has experienced 2 control unit failures and is presently inoperable. I am having a hard time finding a new control unit and am considering other options. I also have a reverse cycle 16,000BTU heat pump. It is adequate down to 0C but requires the generator when on the hook.

[Dockhead]

Originally Posted by transmitterdan

. . . Dockhead's advice about spares is valid. A spare control unit and spare fan will cost about 1/2 the amount of a spare furnace unit. Mine has experienced 2 control unit failures and is presently inoperable. I am having a hard time finding a new control unit and am considering other options. I also have a reverse cycle 16,000BTU heat pump. It is adequate down to 0C but requires the generator when on the hook.

Reverse cycle heat is brilliant when you're on shore power. I envy you! I had it in my last boat and loved it.

Spares for the Hydronic 10 are freely available in Europe. If you contact the UK or German distributors, they can fix you up.

I now have two complete spares. One of them, however, is an M10 which, I didn't realize, is a completely different unit. It is a brand new takeoff from a truck which I got for 500 euros on the Flea. If my present Hydronic 10 dies, I will probably replace it with the M10 which is newer and should be easier to find spares for as time goes by.

For the OP: These devices can go down for a variety of reasons -- glow pin, problem with fuel flow, coked up, bad control board. Mine failed most recently because of a bad burner tube, which was horrendously expensive.

If you are going to be in remote cold places, it would be very wise to have a complete working spare on board, in addition to the diagnostic harness and a set of frequently required spares (control board, glow pin, fuel pump, gaskets and o-rings). And obviously you will want to download and store all the manuals.

You have to decoke them every year or two, depending on the type of fuel you're using and how many hours you're putting on. This is not complicated and you can do it yourself, but you need the gaskets and o-rings. It is said that running them once in a while on kerosene/jet fuel/paraffin greatly extends the decoking interval.

My next boat, which is intended for remote, high latitude places, will have two of them in parallel, one large (10kW) and one small (4kW). Using the small one only when little heat is required will also help prevent coking up -- these things don't like to run for long periods at low power settings. Both can be used at once when you need a ton of heat in really cold weather.

I will also have a day tank for the heaters which can be filled with kerosene for occasional clean-outs, and I'll run the fuel through a Racor filter, instead of straight from the tank as they are usually installed.