Hotwater as well as central heating

[mack3737]

I have a D5W Eber with two radiator type electric fan units for distributing the hot air, since I am mostly on a mooring and do not want to run the engine to creat hot water can I modify the Eber hot water circuit to link into the hot water tank. Do I need to fit a non return valves on the engine c/w to heater coil to prevent the Eber warming the engine? Do you think there is a problem of the Eber warming the engine? Anybody got a similar set up?

 

[vyv_cox]

I remember a long thread on this subject about a year ago. Might be worth a search.

IIRC the best way to go is with a double coil calorifier but the consensus was that it can be done with a single coil. Suggestion - a normally closed solenoid valve on the engine coolant circuit powered from the ignition switch would prevent Eber water from entering the engine but would open to save any problems when the engine is running.

 

[DipperToo]

I went through all sorts of hoops and loops over this - with much conflicting advice (especially as the engine system may well operate under pressure) I fitted a dual coil calorifier to the current boat. Last boat I simply did away with the engine to the calorifier circuits and used the Eber. I guess if I was really going to use both circuits I would somehow rig it so that with changeover valves it was either engine or Eber to avoid the pressure issues.

Stewart

 

[Cloven]

We have the set-up you describe (I think). The calorimeter is twin coil - one circuit for the Eber, another for the engine - plus a 240V immersion heater. So, we can get hot water from the mains when pugged in, the engine if it is running or the Eber (D4W) if neither of the above. With the Eber running or 240v on, there is no engine heating as only the tiny amount of water in the "engine" coil is heated and unless the engine is running, it does not circulate through the engine.

We have put in a system of valves so the Eber can be used to provide hot water only, space heating only (via the matrix fan units) or both at the same time.

The biggest problem in setting all this up was the final bleeding of the Eber system, simply because parts had difficult access. However, it now all works a treat.

 

[seamaster30]

Assuming you have a single coil calorifier, you would have to have some form of changeover valves to switch between heating by engine or eber.
I had a twin coil system on my last boat and it still leeched the heat from the tank into the engine because the engine was above the heater coils in the tank so it 'worked in reverse' ie hot water in the tank heated the second coil attached to the engine, and as hot water rises, created a flow to the engine with the cold water going back to the coil in the tank. - Sufficient to cool the tank down over night and a right pain.
On my new boat I kept the single coil system and just switched the engine connections over to the Mikuni heater.
When the time comes to change the tank I will consider a dual coil system but will pay attention to the pipe runs to avoid the same situation I had before. The cost of the tank far outweighs the saving I will make by using the 'free' engine heat for now.

 

[Cliveshep]

I fitted a calorifier system on a previous boat and also heated the engine/cooled the water. The simple solution was to prevent the gravity circulation by putting a loop in the "flow" pipe which solved trhe problem.

 

[seamaster30]

Yes, there are easy ways to avoid it if there is space, but given the location of the tank (between the two engines) and the hight of the items, there was no suitable plumbing solution.
I toyed with the idea of putting a valve in the pipe, but sold the boat before I got around to it /forums/images/graemlins/smile.gif

 

[boatmike]

I experimented with various ways of rigging an eberspacher water heater. I already had an Eber D4 Airtronic so didn't need cabin heating. I do have a twin coil Calorifier tank however. First I fitted the Eber to one coil and the engine to the other as it seemed the obvious thing to do. Due to the fact that Calorifiers only have about 3/8in dia pipes though this restricted the flow and caused the eber to switch in and out all the time which meant it took about 45 minutes to heat the tank. So I then created a circuit through the engine and both coils ("siamesed"the pipes in other words) so that with the eber running, even heating the engine water as well it only takes 30 minutes because the eber runs almost continuously. If you did the same you could also utilise the engine cooling water to heat the boat if you wanted. Sounds good to me! Also pre-heats the engine before starting which can't be bad...

 

[lw395]

Heating the engine is often a good thing, if counter-intuitive. The extra heat capacity stops the eber from short-cycling, and the heat is slowly released into the boat anyway.