De-mister Heater Matrix

[Greg2]

I have just fitted an Eberspacher heater matrix (I think they may be made by Isotherm with an Ebby badge stuck on) to take heat from the engine to warm the cockpit and de-mist the windscreen. The unit is mounted low in the boat in the engine bay (has to below the coolant header tank) with ducting runs of between approx. 2m and 4m (maybe 5m for the longest) all of which is lagged. Went out on the river today and the engines ran up to operating temp (80 degrees), which is fairly constant on the river and at sea cruising speeds. I was disappointed to get only lukewarm air from the vents and whilst it cleared the screen (so not all bad ) it didn't add much in the way of warmth.

Not sure if anyone had experience of these systems but the question is can I get anything warmer out of the system or is 80 degrees simply not hot enough?

Interestingly the spec for an Eberspacher Hydronic water heater (for heating systems) says it heats the water to 80 degrees so the temp may be okay…

I should add that the coolant supply pipe was hot and the return pipe cooler so the water circulation appears to be okay...

 

[bluejasper2]

I have just fitted an Eberspacher heater matrix (I think they may be made by Isotherm with an Ebby badge stuck on) to take heat from the engine to warm the cockpit and de-mist the windscreen. The unit is mounted low in the boat in the engine bay (has to below the coolant header tank) with ducting runs of between approx. 2m and 4m (maybe 5m for the longest) all of which is lagged. Went out on the river today and the engines ran up to operating temp (80 degrees), which is fairly constant on the river and at sea cruising speeds. I was disappointed to get only lukewarm air from the vents and whilst it cleared the screen (so not all bad ) it didn't add much in the way of warmth.

Not sure if anyone had experience of these systems but the question is can I get anything warmer out of the system or is 80 degrees simply not hot enough?

Interestingly the spec for an Eberspacher Hydronic water heater (for heating systems) says it heats the water to 80 degrees so the temp may be okay…

I should add that the coolant supply pipe was hot and the return pipe cooler so the water circulation appears to be okay...

Hi Greg have you bled the system there may be a parsial air blockage which would reduce water temp. I do not have the same system
just webasto hot air i do not think you will get the same temps with water unless you run radiaters off it.

 

[Robg71]

Its exactly the same principal as the heater in your car, so should do exactly the same job...
I agree, you may have an airlock.

 

[MarieK]

What did u use to lag the pipes?

 

[Greg2]

What did u use to lag the pipes?

I used the bespoke lagging from Webasto.....I think it is Thinsulate.

 

[Greg2]

Thanks for the replies. Maybe there is an airlock.....I did all the installation myself bar tapping into the engine, which was done by an engineer as I didn't have the time. He did say it was lovely and warm when he ran it up so I wonder if this could be it. Mind you, the pipes did indicate that water was flowing.....

 

[bluejasper2]

Thanks for the replies. Maybe there is an airlock.....I did all the installation myself bar tapping into the engine, which was done by an engineer as I didn't have the time. He did say it was lovely and warm when he ran it up so I wonder if this could be it. Mind you, the pipes did indicate that water was flowing.....

hi greg water will flow through an airlock but not enough to completly fill pipe so your pipes will feel warm but not hot,like a radiater at home warm untill you bleed it to get full flow and too hot to touch:encouragement:

 

[Greg2]

hi greg water will flow through an airlock but not enough to completly fill pipe so your pipes will feel warm but not hot,like a radiater at home warm untill you bleed it to get full flow and too hot to touch:encouragement:

Thanks for this. I am no plumbing expert but had been thinking Thant maybe some water would still get through. Just got to work out how to bleed the system.....don't think the is a bleed screw!

 

[LittleShip]

Thanks for this. I am no plumbing expert but had been thinking Thant maybe some water would still get through. Just got to work out how to bleed the system.....don't think the is a bleed screw!

What is the heat output of the heater, it maybe working correctly but not providing enough heat for your needs.

Tom.

 

[aquapower]

I have just fitted an Eberspacher heater matrix (I think they may be made by Isotherm with an Ebby badge stuck on) to take heat from the engine to warm the cockpit and de-mist the windscreen. The unit is mounted low in the boat in the engine bay (has to below the coolant header tank) with ducting runs of between approx. 2m and 4m (maybe 5m for the longest) all of which is lagged. Went out on the river today and the engines ran up to operating temp (80 degrees), which is fairly constant on the river and at sea cruising speeds. I was disappointed to get only lukewarm air from the vents and whilst it cleared the screen (so not all bad ) it didn't add much in the way of warmth.

Not sure if anyone had experience of these systems but the question is can I get anything warmer out of the system or is 80 degrees simply not hot enough?

Interestingly the spec for an Eberspacher Hydronic water heater (for heating systems) says it heats the water to 80 degrees so the temp may be okay…

I should add that the coolant supply pipe was hot and the return pipe cooler so the water circulation appears to be okay...

The problem with a matrix connected to the engine is that its never hot until you have engine upto temp which takes a while on the river and its difficult to maintain a temp of 80 deg at the matrix even when running at sea, you need heat before leaving the mooring when using as a de mister so this set up was never as good as when connected into a Hydronic or taking warm air straight from the eberspacher/webasto.

 

[Greg2]

Not sure of the heat output but as Robg71 says, I had expected it to do what one in a car does.

I had thought about an Ebby or Webasto being better as it is quicker heat but got the matrix for an excellent price from EveryThing Boat and thought I would give it a go.

 

[aquapower]

Not sure of the heat output but as Robg71 says, I had expected it to do what one in a car does.

I had thought about an Ebby or Webasto being better as it is quicker heat but got the matrix for an excellent price from EveryThing Boat and thought I would give it a go.

They never were great, that's why most boat builders now use the electronic diverted from eberspacher, you also have quite a run of ducting which even when lagged will still not hold heat.

 

[Greg2]

They never were great, that's why most boat builders now use the electronic diverted from eberspacher, you also have quite a run of ducting which even when lagged will still not hold heat.

If it isn't an airlock and I am not going to get any better then I think another Ebby is on the cards as it will improve the heating of the boat overall as well as sorting the cockpit heat/de-misting. At least the ducting is all in place now

 

[Robg71]

Does any of the glazing companies do the electric heater mesh in there glass like in cars these days. Not a valid cheap retrofit I realise, but food for thought.

I had not seen these electic divertor valves in their catalogue. Must update mine..

 

[David2452]

Problem with those matrix (Indel Webasto) is they are really an AC part and don't work well, to be effective, a heater matrix like in a car should have a separate header or buffer tank at each end. Truth to tell you would do better with a car heater matrix which is designed for the task, customer (and my) disappointment in the past means I will no longer use matrix even with coolant based heating systems.

 

[Greg2]

Problem with those matrix (Indel Webasto) is they are really an AC part and don't work well, to be effective, a heater matrix like in a car should have a separate header or buffer tank at each end. Truth to tell you would do better with a car heater matrix which is designed for the task, customer (and my) disappointment in the past means I will no longer use matrix even with coolant based heating systems.

Pity I didn't speak with you before embarking upon the project I guess I just assumed that it would be as good as the car....

Oh well, back to the drawing board if the airlock theory doesn't pan out

 

[David2452]

Pity I didn't speak with you before embarking upon the project I guess I just assumed that it would be as good as the car....

Oh well, back to the drawing board if the airlock theory doesn't pan out

They will work if you can get the temperature up a bit but I guess that's a non starter.

 

[Greg2]

They will work if you can get the temperature up a bit but I guess that's a non starter.

Should have plumbed it in it the other engine.....it has overheated every now and then

 

[lynall]

Both my cars have capilliary temperature gauges so are pretty accurate, and the heater is pretty much the same in both cars, okay at 90 degc, barely passable at 80 degc and once down to 75 degc hardly worth the effort, doesnt seem to matter how much air goes over the matrix its the temp that seems to be important.
I dont know how big your matrix is, but have heard good things about the universal rally style ones as found on e bay.

 

[David2452]

Both my cars have capilliary temperature gauges so are pretty accurate, and the heater is pretty much the same in both cars, okay at 90 degc, barely passable at 80 degc and once down to 75 degc hardly worth the effort, doesnt seem to matter how much air goes over the matrix its the temp that seems to be important.
I dont know how big your matrix is, but have heard good things about the universal rally style ones as found on e bay.

A very good example and unusually with objective measurements to boot, as you say it is the thermal input (less efficiency losses) that denotes the output. I am often asked by customers why for simplicity I will not fit say two 3kw matrix with a Webasto Thermo Top C for instance, on the face of it a good combination, 6kw to nicely load a 5.2kw heater and prevent over cycling. Problem is that an advertised output is measured at a temperature far above that given by coolant heaters, normally in excess of 90⁰C which in a fully warmed up motor is fairly normal and really the design application for them. I now always use radiators with the largest surface area and coolant capacity I can squeeze in, it leads to far less disappointment, though more expensive in labour costs, surprisingly not so much increase (if any) in material cost.