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Old 19-10-2016, 22:47   #1
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Hydronic heater installation.

Hi,

I am about to embark on a heating project for 'Spirit of Sobraon'.

We have reached higher latitudes on our voyage toward Alaska and now is the time to finally fit heating to the boat. After almost 7 years of never ending summers some are questioning our sanity.

I will be installing an eberspächer 10 hydronic heater and I was hoping for some input from those of you who are in the colder climates with similar systems as to there plumbing and installation.

We have arrived in Korea and have sourced PEX Piping and fittings from a local house hold hydronic floor installation company and I also have rubber hot water hose and fittings that I can use. The unit should arrive from Europe soon.

I will list a few questions that you may be able to help us with. Not having any boating or English speaking technicians here in Korea is making it a little difficult to find good information.

1. My intention is to plumb the Thermostatic controlled fan heaters in Parallel. Is this better than Series?

2. Should I also install isolation solenoids to assist zoning or just use the fan thermostats?

3. Is PEX better than Rubber heater hose? My current fresh hot/cold water system is PEX.

4. I intend to use a plate heat transfer block from the engine in series with the hydronic return line to make use of engine waste heat and lower heating fuel use whilst motoring. (Good or bad?)

5. I have a very good 40 litre waste heat/240v hot water clorifier connected. It only has one heat coil used by the engine and a 240v immersion heater so I intend plumbing a plate heat exchanger with a thermostatic mixer valve in parallel in the hydronic system then pass the hot fresh water line from the clorifier through it to provide instantaneous hot water whilst the heater is running and the engine and power are not available . (Good or Bad?)

6. The eberspächer 10 will be mounted in a lazarette locker to facilitate ease of supply and exhaust. This will put the unit about 1 mtr above the lowest fan heater on the boat. Is this really a problem? There is conflicting data on the Eberspächer website that quote 500mm as the maximum. I will also install a header tank above the heater.

7. The current intention is to install 4 thermostat controlled 1.7kw fan heaters and the hot water heat exchanger with the possible inclusion of a towel warmer radiator in the head at a later date. Is the eberspächer 10 big enough in your experience? It specs say that it's output is about 9.8kw on start up on high. The heaters are rated at 1.7kw. What is not clear is how many kw/btu's they consume.

8. Condensation is a concern. We have not had the problem in the past as we have been in the tropics and the boat is very well insulated except for the cabin top side bulkheads and port holes. Running our 1kw Air conditioner, whilst in marinas, in extreme heat and humidity kept the boat at more than 10 degrees C below outside temps. Any thoughts?

I will be documenting and posting the information about the install on our Projects and Maintenance - Blog Summary View page of our website. Information for RV's is readily available on the net, however I haven't found much information for boat installations. Hopefully it will be of assistance for those that follow our project.

Commercial installation for us is not an option as we have not found any boating experts in Japan or Korea. I have seen some of the US quotes on installation on boating blogs and they are staggering. Considering it is really only plumbing and some carpentry I don't see the job as beyond most boat owners.

Thanks for any input.

Garry
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Old 20-10-2016, 02:29   #2
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Re: Hydronic heater installation.

These folks -- http://www.twoatsea.com/i-took-a-shower/ -- installed a hydronic system with a single single blower and heat exchanger for hot water.

We hope to add a similar system in the coming months, so I am looking forward to seeing how you do it.
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Old 20-10-2016, 02:36   #3
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Re: Hydronic heater installation.

One of the best threads I've read on this subject...


http://www.cruisersforum.com/forums/...er-149641.html
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Old 20-10-2016, 13:29   #4
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Re: Hydronic heater installation.

Quote:
Originally Posted by GILow View Post
One of the best threads I've read on this subject...


http://www.cruisersforum.com/forums/...er-149641.html
Yes post your questions in there and we will all help and benefit from your experiences.

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Old 20-10-2016, 17:47   #5
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Re: Hydronic heater installation.

1.2kw is 4000 btu. 9.8kw is 33,000 btu.

I don't see how you can connect the raditors in parallel. They need flow.

If you are heating domestic hot water with the system, then it is good to have a cut off circuit that allows the system to heat water without going to the raditors for summer use.
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Old 20-10-2016, 18:32   #6
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Re: Hydronic heater installation.

Paul thanks for the reply.

The question of parallel V's series is about efficiency and redundancy. From what I have read and my understanding of fluid dynamics ( ie. Pascals Law) the system can be and are plumbed either way. In parallel balancing valves may be required??.

The advantages of a parallel circuit is that all radiators are getting the same temperature + or - loses of the piping. It also allows for efficient and effective Zoning meaning for instance that the hot water circuit could be run in summer without heating the boat or any of the cabins can be individually isolated or controlled.

In a series circuit the system loses heat after each radiator, therefor the heater furthest from the heating unit gets the least heat and no unit can be isolated. One on, all on.

The only advantages I can envisage with series is simpler system and less pipe work.

So far as Kw and BTU's. The manufacturers seem to have a bad habit of inflating and disguising figures to help sales. For instance a Hydronic 10 is not 10kw continuous. It is actually 9.8kw at start up.
The problem with sizing the Fan Heaters is that the manufacturers do not state what the 1.7kw actually means. Is it what the unit actually consumes from the hydronic circuit or is it what it produces in heat and air flow?

The reason for my questions are to ascertain from members who have systems, what they have in their boats, how they are plumbed and what is their experience.

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Old 20-10-2016, 18:42   #7
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Re: Hydronic heater installation.

I will reply and share in the morning

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Old 20-10-2016, 21:13   #8
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Re: Hydronic heater installation.

My hydronic system is plumbed in series with a 8700btu and 6000 btu raditors. The heater is 33000btu. Works well so far with individual thermostats on each raditors. One thing I should have done better was to think out the heat being displayed by the hoses better. Right I warm some lockers that I'd rather keep cool. This is not an ebspacher unit.
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Old 20-10-2016, 22:12   #9
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Re: Hydronic heater installation.

Make sure you locate circulation pump/pumps so they are easy to get to. I recently installed 1 larger pump to replace the 2 marsh pumps. Less amps and longer brush life.
All my heat exchangers are in series, my understanding is the heated fluid needs to flow fairly easy through the whole system. We do have the ability to isolate for summer use.
Sure Marine in Seattle is a good go to place for help.
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Old 20-10-2016, 22:58   #10
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Re: Hydronic heater installation.

1. Serial works ok for small systems, 2-3 fan coils. More complex heating loops will do better with parallel. If you pipe it "reverse return", you don't need balance valves, but uses more pipe. Direct return needs balance valves to balance pressure drops across the branches.

2. I would not use solenoids as you want to maintain system flow rate. This keeps the boiler happy. For larger systems one could use a primary/secondary pumping system. But for a small boat system that can't take too much pressure, it can't be done. So constant flow is your friend.

3. PEX is the best with higher working pressures and temperatures then hose. o2 barrier pex would be best, but normal pex has less permeability then hose anyway.

4. That can be done. You will want to put that in the return line to the boiler and just before the boiler inlet.

5. Hum, If your trying to heat water instantly with a plate and frame, it's not going to work (not enough delta T across the plate and frame). You can use it to heat the clorifier water. What I would do is pipe the clorifer loop with the return boiler water and use the engine plate and frame to heat the loop when engine running. Far less complex that way. But your only going to get about a 20degree C delta across the typical plate and frame at best, which is not at all enough for instant hot water.

6. At issue is working pressure of the boiler which is "not much". Though locating the boiler at the high point of the system would probably be OK. Pump selection and total system pressure is the issue. Due to the lightweight pressure vessel of the boiler it can't take much kPa like a home system.

To clarify, I have never installed a boat hydronic system. But I design hydronic systems for highrise hotels and such. Along with a bunch of other things. I also read installation manuals for fun.
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Old 22-10-2016, 01:00   #11
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Re: Hydronic heater installation.

Sailor Chic,

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..



I will use this thread to keep the project undated as a how too ( or not too) install hydronic heating.

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Old 22-10-2016, 04:41   #12
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Re: Hydronic heater installation.

Quote:
Originally Posted by sobraon View Post
Sailor Chic,

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..



I will use this thread to keep the project undated as a how too ( or not too) install hydronic heating.

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Sailor Chic is the pro, and so you should look to her for the definitive word. To my amateur eye, three comments:

1. I doubt that running the domestic hot water through that second heat exchanger is going to do anything after. For two reasons: (a) it's in the wrong place -- should be AHEAD of the calorifier where you will get more Delta T, and not after; and (b) will the heat exchanger transfer enough heat to a running stream of water, to do anything useful? That's an objective question which can be answered by running numbers (temperatures and flow rates in both sides). But I think the second heat exchanger is superfluous. Just let the hydronic system heat up the calorifier and you're done.

2. You're going to need manifolds for balancing that parallel arrangement, won't you? Will you have space for that and all the piping? I've never seen a boat with a parallel hydronic system; there must be some good reason why they're all set up series.

3. Don't use a towel warmer in the heads -- these don't heat space very well. I would use the biggest radiator I could find to pump as much heat in there as possible. You'll want heat in there even in warmish weather -- to dry it out. And not just the towels.


For whatever (little) it may be worth.

I'm going through a similar exercise, not adding hydronic (I already have that), but adding heat exchangers to capture and use waste heat from main engine and genset, and adding two radiators and a bus heater working directly on waste heat, kind of a parallel hydronic system.
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Old 22-10-2016, 05:05   #13
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Re: Hydronic heater installation.

If this installation will be a closed loop make sure the pex you use has an oxygen barrier. If there are any ferrous components in the system they will be eaten quickly if you use potable water pex. As S.C. has mentioned, install the piping in a reverse return. It will ensure equal water flow thru each heater & eliminate the need for balance valves.
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Old 22-10-2016, 06:11   #14
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Re: Hydronic heater installation.

Dock Head and Sailor Chic thanks for the input.

The very reason for this thread is to bounce ideas so that we get the install right and hopefully help others in the future with installs.


a. My reasoning on the second heat exchanger is that our hot water clorifier is a 20lt unit. It is heated via the engine and the 240V immersion heater. It doesn't have an extra circuit for another hydronic circuit. If the heat exchanger was before the unit there will be no flow unless the hot water circuit is flowing, therefor, if there is only cold water in the clorifier there would be very limited heat transfer. We would have to waste at least 20 to 40 litres before we would get anything more than warm water in the circuit. The idea is that when at anchor for a few days and the residual heat has dispersed from the clorifier the hydronic heater could be run to heat water for on call hot water. Using the summer valve would mean it would be available even in warmer weather. So far as the inefficiencies I can only go by others experience. The two at sea blog I Took a Shower! – Two At Sea say that their system works well.

b. The heat transfer in the parallel circuit is an area I have no experience with. I do know fluid dynamics. Pascals law states that pressure is transferred equally by the fluids so flow unless restricted should be balanced.

The huge advantage of the system is zoning and even heat transfer to each heater. Spirit of Sobraon is a big boat. The eberspacher website show all of their big systems as parallel in their brochures.

I would prefer series as it is a lot easier and less cost however pipe work is easy and not a huge part of the overall project. I am hoping that by running the main 22mm pipes together along the centre of the cabin sole it will warm the floor and keep the bilge area dry when the heater is running.

Sailor chic I assume the system I have drawn is what you refer to as direct return.. I am not sure what you mean by reverse return.

c. The towel heater we are looking for is a radiator style 2400btu unit.




I am not sure what the heat output of the unit is however I was hoping that it's output when confined to the small area of the bathroom would provide heat to aid drying of laundry at the same time as heating the head.


Cheers
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Old 06-11-2016, 18:41   #15
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Re: Hydronic heater installation.

Where is your boiler unit installed?

The major components for the Hydronic Heating System should arrive at the boat this week.


Just in time as temperatures in Korea this week have been plummeting.

I am still deciding on the location of the Eberspacher H10. I have two options:

1. In a Lazarrete locker at the stern of the boat or:

2. in the rudder locker in the aft cabin.

The 1st option is the more problematic. The unit would have to be installed higher than 500mm above the lowest component of the system. It will necessitate breaching a water tight bulkhead to install electrics and plumbing. The unit will be more exposed to the elements than the second option. Exhaust would exit the stern.

The 2nd option is easier but has it's downfalls. It would comply with the 500mm recommendation. It would not require passing the plumbing and wiring through the water tight bulkhead. It would however be inside the boats interior. The exhaust would exit the stbd side aft of the hull. Noise may be an issue.

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