Eberspacher Rheostat

[Porthandbuoy]

I have a bit of a problem with my newly installed Eber Airtronic D2 system. When I turn it on it lights first time and blasts out plenty hot air. But, when I try and turn it down nothing happens for a few minutes then the pump rate slows . . . and slows . . . and slows, until it stops, at which point the fan slowly winds down to a halt.
So, flat out no problem. Attempt to turn it down, however slightly, and it eventually stops. There are no flashing LED codes, just the green LED on the rheostat dial to say the heater is 'on'.

Any advice welcome.

 

[Alpha22]

Mine does that.....

Check how warm the area is where the heater is installed. Mine is in the engine bay on a 30 foot mobo, but it is amazing how hot it is in there with the heater running. Mine picks up its "fresh" air from the engine bay so it starts to shut down if I turn it down on the rheostat as the sensor is in the air intake. It thinks it has warmed all the air up enough, depending on the setting. It will eventually fire back up on it's own if left long enough.... about an hour or so.

If I open the engine bay above the heater, it behaves. I need to feed it with "real fresh" air from the cockpit.

 

[alahol2]

Second what Alpha22 says. Mine is in a cockpit locker. If I leave the locker closed it will eventually shut down. I am also unable to 'turn it down'. Leave the locker open/ajar and I have full controllability.

 

[Porthandbuoy]

Nice to know I'm not alone!

Mine is installed under the cockpit sole in the engine bay so it could be getting a bit warm like Alpha22's.

Looks like I need another metre or so of hose and duct the air in from outside.

 

[Alpha22]

Nice to know I'm not alone!
Looks like I need another metre or so of hose and duct the air in from outside.

Snap!!!!!

 

[VicMallows]

Looks like I need another metre or so of hose and duct the air in from outside.

If you then use your boat in REAL winter you'll find that the heater is inadequate.

 

[David2452]

Just bung in a remote temperature sampler instead of the one in the circulation air inlet of the unit, that way you can leave the heater drawing air from somewhere a little less chilly in the depths of winter.

 

[Porthandbuoy]

Just bung in a remote temperature sampler instead of the one in the circulation air inlet of the unit, that way you can leave the heater drawing air from somewhere a little less chilly in the depths of winter.

I don't get it. If the cabin's getting a bit toasty I should be able to turn the rheostat down. It is not a temperature sensor/controller, it should simply slow down the pump and fan.

The sensor in the air inlet is for overtemperature protection. Turning down the rheostat should reduce exhaust, air and, as a result, heater enclosure temperatures, so why does my heater (and others) conk out when we turn them down?

If it is the inlet sensor then it would be most affected when running the heater flat out, not turned down.

 

[David2452]

"The sensor in the air inlet is for overtemperature protection. Turning down the rheostat should reduce exhaust, air and, as a result, heater enclosure temperatures, so why does my heater (and others) conk out when we turn them down?"

That's the last time I offer help on here other than to say this.

Firstly, the temerature sensor in the air intake is not for over temperature protection, that device is on the outlet end of the heat exchanger. Yours is currently sampling air going into the heater and not sensing it in the cabin area like a remote probe will do. The only time a basic install without remote sensor install is effective is when the air is drawn from inside the space to be heated otherwise the rheostat setting bears no relationship to what happens in the cabin to a large extent. But what do I know I'm only a factory appointed and trained dealer for Webo & Mikuni and of course Ebos are so much different.

 

[fireball]

Blimey, nearly had take off!
I understood the rheostat to be as phb thought - and that is how it seemed to work with my old d1lc and I think the new d3lc so if the d2 is different then that's interesting.
Ta

 

[alahol2]

I always thought mine worked the way David2452 says.
If drawing the air from the locker and the locker gets too warm the heater shuts down. Similarly if you turn down the rheostat then the thing thinks the locker is too warm at a lower temperature so, again, it shuts down.
The only way to get full control via the rheostat is to keep the locker cool then the inlet air is always cooler than the rheostat says it wants to be so it keeps running at the lower temperature output.

I know what I mean anyway...

 

[David2452]

Sorry for the earlier outburst but I do sometimes get a bit exasperated and wonder why I bother.


I know what you mean too Alahol2, and you are entirely correct. The problem most amateurs have with the Ebo air intake temperature sampler is that unlike the Webo it is inside the control box so you can’t see it and it’s not on the parts list, therefore some people think there is not one present, or worse, confuse it with the overheat / flame detector as in this case, there is one but it’s not replaceable, in fact if it is found to be faulty when one connects up the diagnostic kit the default (and cheapest) repair is to fit an external temperature sensor thus bypassing it and saving the customer having to pay for a new control box. In the current case (without physical inspection) I would try to run an inlet duct from the heated area or one bringing in fresh air, possibly a combination with a blender valve to allow for differing ambient temperatures, but would always fit a remote sensor unless the intake air is always being taken from the heated space. The other issue I would have with this installation, unless I have misunderstood, is that the combustion air intake is being taken from the same locker as air to be warmed and distributed, a definate no no.

 

[KevB]

Mine picks up its "fresh" air from the engine bay

Not a good place to pick up the fresh air. If anything goes wrong with the exhaust from the unit or your engines you start pumping co2 through your air vents.
The fresh air should be picked up from an open air source like the cockpit.

 

[john_morris_uk]

Sorry for the earlier outburst but I do sometimes get a bit exasperated and wonder why I bother.


I know what you mean too Alahol2, and you are entirely correct. The problem most amateurs have with the Ebo air intake temperature sampler is that unlike the Webo it is inside the control box so you can’t see it and it’s not on the parts list, therefore some people think there is not one present, or worse, confuse it with the overheat / flame detector as in this case, there is one but it’s not replaceable, in fact if it is found to be faulty when one connects up the diagnostic kit the default (and cheapest) repair is to fit an external temperature sensor thus bypassing it and saving the customer having to pay for a new control box. In the current case (without physical inspection) I would try to run an inlet duct from the heated area or one bringing in fresh air, possibly a combination with a blender valve to allow for differing ambient temperatures, but would always fit a remote sensor unless the intake air is always being taken from the heated space. The other issue I would have with this installation, unless I have misunderstood, is that the combustion air intake is being taken from the same locker as air to be warmed and distributed, a definate no no.

Can I just check something with you? I fitted our Eber exactly according to the instructions. Its in a cockpit locker which is very large - as in I can stand up in it! If I recall correctly the combustion air and the air for the heating is drawn from within this locker, but there is a separate temperature sensor which I fitted in the main saloon of the boat so I never have problems with the thing not controlling itself properly. It regulates its fuel supply etc according to the output required. I have never had any problems with the installation, but your comments about drawing combustion air and air for the heating from the same place as being a definite no have left me wondering. Can you comment please. (Its an Eber D4)

 

[David2452]

In such a large locker (more like a cave by the sound of it), my personal view is that it should be fine assuming there is some ventilation but all the manufacturers training courses say it’s not done. I was really talking about doing it in a small locker space. One reason is that warm combustion air is not as good as cold for efficient combustion but personally the fact that most DIY fits never have the CO2 set to get the cleanest burn anyway is probably more important. Mikunis actually actually pass the combustion air in a larger tube surrounding the exhaust tube but they are fine if the CO2 is set correctly.

 

[Porthandbuoy]

I think I've got it now David

Agree combustion and air to be heated drawn from the same source is a no-no. At the moment my combustion air is drawn externally and air to be heated from the engine bay. Arsy-Versy I know, but will be rectified when I get some more ducting.

Thanks for the explanation regards the remote temp sensor. I'll look into that but there's not much/nothing in the literature that came with my kit (new, not ex-truck).

 

[john_morris_uk]

In such a large locker (more like a cave by the sound of it), my personal view is that it should be fine assuming there is some ventilation but all the manufacturers training courses say it’s not done. I was really talking about doing it in a small locker space. One reason is that warm combustion air is not as good as cold for efficient combustion but personally the fact that most DIY fits never have the CO2 set to get the cleanest burn anyway is probably more important. Mikunis actually actually pass the combustion air in a larger tube surrounding the exhaust tube but they are fine if the CO2 is set correctly.

You are right - its more of a spare cabin than a cockpit locker. Its on a Westerly Sealord - so you will know the wort of thing. It even has its own window.

I wasn't aware that there was an adjustment for correct burn available. Certainly nothing in the DIY instructions about it - perhaps not surprising. I can certainly get a CO2 monitor to check the gases if that is what is necessary - should I worry about the burn as its been running very well for the last few years.

 

[David2452]

should I worry about the burn as its been running very well for the last few years.

It's quite important really, a bit like driving down the road with the choke out all day if it's on the rich side which leads to premature coking up not to mention using more fuel, exhaust smoke etc. If it's too lean it can (& does) lead to premature glow plug and screen failure, poor starting, overheat etc depending on how far it is out. All symptoms similar to an old carburettor petrol engine. The units leave the factory pre set but the addition of long exhaust runs and hot air ducting can and do alter that setting to a greater or lesser extent depending on how long they are, whether a silencer is fitted etc.

 

[VicMallows]

but personally the fact that most DIY fits never have the CO2 set to get the cleanest burn anyway is probably more important.

Please can you tell me how this is achieved on current heaters? .... purely of academic interest at present since my (1986 ish) Eber D1L certainly has no means of adjustment which could possibly effect CO2.

Thanks,

Vic

 

[David2452]

Hook up the diagnostic kit and set the CO reading to spec. happens by adjusting either the fan speed or the pump rate dependant on model, age etc.

Webos and Mikunis are much easier and can be done without any kit apart from the CO2 analyser.