Why does my Diesel auxilliary heater not show any life?

GWAYGWAY

GWAYGWAY

Free Member
Joined
Sep 6, 2014
Posts
4,213
Likes collected
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Location
Dover
Funster No
33,216
MH
Hymer ML I 580
Exp
4 years
I tries to fire up the auxilliary heater on my ML1 and no life was apparent. It says in the MB handbook the 'proper ' diesel heater will cut out at 1/4 tank but that is a different beast to mine which only comes on with the engine.. The LED light is not on so I dived into the various fuseboxs looking for why it is dead. No joy so I will try filling the tank up tomorrow and see what happen then.. I have never used it in battle before but if we are off the the East next week it might prove worthwhile to have.. Is there another reason I have not figured out????? The handbok are a nightmare to try and find out the technicalities as they seem to hold all the information to service centres who themselves have no idea what the stuff is.
 
It might help Funsters to help you if you say what the name of your heater is ? A webasto ?
 
I 'exercised' mine on the MH last weekend as they recommend running it monthly. It failed to start the first time but after switching it off and then on again it started.
The one on my Landrover has no manual switch and is supposed to come on if the temperature is 4C or less. I don't think it works but is next to impossible to test unless we get a really cold snap.

edit; The one on the MH (Rapido) is an Eberspacher, that on the Landrover is Webasto. They seem very similar.
 
Eberspachers need monthly exercise. But there could be other problems. I'm assuming the MB auxiliary installation lacks a control panel showing an error code.

You may need to visit a specialist Eberspacher tech.

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The diesel "supplementary" heaters are usually fully autonomous , and require a combination of low ambient , and also engine temp within a certain range, some also have fuel level feeds to stop them in low fuel situations . Frequently the problem is with the ambient sensor . The next one is flame out sensor . Then dosing pump faulty ! They are also sensed for low voltage. They are good when they work but can be costly to bring back into service . HTSH
 
I have a wabesto thermo top c on my hymer.
Struggling to find out how to use properly though.
Any suggestions?
 
Thanks for that. I have the instructions, but it's using it in conjunction with the Adle heating in the hab area.
 
PhilandMena said:
It might help Funsters to help you if you say what the name of your heater is ? A webasto ?
Click to expand...
It is whatever Mercedes deemed was wanted, It is probably an Eperspascher or whatever or could be a Webasto, Nothing tells me what it is, it worked when I last tried it but now there is no power light on the dash switch. The habdbook is rubbish and I have checked the fusues and all are correct.. Is it a low fuel device???? I do not know but I need to fill up to find out. The dealers did not know I even had one let alone what it is. It does nothing other than add heat to the engine cooling system which has the engine running to do that and seems a waste of diesel to put heat into a system the radiator is trying hard to dump at the other end to atmosphere.At the mone I was trying it the temperature was 8 degrees. I Realise modern diesels take a long time to warm up and it is the get the system up to heat for the cab heating to work. but it seems a bit superfluous, It does work normally if I want it but this lack of electrical power must be cutout or the like. It is 1/8 from empty at the moment so a tank full will tell me tomorrow, when I go and prepare for my next trip to euroland.

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Most Truck "Night Heaters" will not work below 1/4 Tank. (I know, I was that soldier!(y)) Moral of that tale NEVER park up in February without at least 1/2 a Tank!.:cry:. One "Gaffer" used to go balistic,:mad: as the lads used to set the timers so the wagon cab was "toasty" when you arrived to pick it up!.:D2(y)

I have that system on the Rapido which is a Merc base, (allegedly) never had to use it yet, so don`t even know if it works?. Maybe I should try it out sometime?.
 
Theonlysue said:
I have a wabesto thermo top c on my hymer.
Struggling to find out how to use properly though.
Any suggestions?
Click to expand...


Hi Sue best suggestion I can give is if you turn it on let it run for at least quarter hour before turning it off ..that way you are sure they have reach full temperature and it will go into the shut down sequence .....a couple of mates have been fitting them in there vans ,turning them on to show other mates how good/hot they are then 1 min later off causing them to soot up then not work ..always left the ones I have had on almost 24/7 as ,,@Busman will testify when he parked up next to me one night at Southport after the silencer came off :D
 
My Merc version has a dashboard switch. It will fire up with engine running or not provided the engine is fairly cool (just not run up to temperature). I use it all the time - why start a cold engine if you don't have to?
 
I filled up today and the heater works again, So all you Sprinter base vans, you have a cutoff switch at 1/4 tank to save you running out on the road. Wasted a load of tiime looking at fuses, but I live and learn.

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is it a cut of device or is it just the pickup pipe stop short of the bottom of the tank
 
PeteH said:
I have that system on the Rapido which is a Merc base, (allegedly) never had to use it yet, so don`t even know if it works?. Maybe I should try it out sometime?.
Click to expand...

Used mine today just to warm her up and run the engine up as not using her.
I make a point of using mine as it takes ages to get the engine up to temp.

Mine operates via a multi with on the dash along with the air con and run on cab heater :)
 
tonyidle said:
My Merc version has a dashboard switch. It will fire up with engine running or not provided the engine is fairly cool (just not run up to temperature). I use it all the time - why start a cold engine if you don't have to?
Click to expand...
Mine only works with the ignition on - have you adapted it to work with ignition off? Sounds like a useful mod. I can certainly switch mine on even if ambient temperature is well above freezing.
 
paddymcc said:
Mine only works with the ignition on - have you adapted it to work with ignition off? Sounds like a useful mod. I can certainly switch mine on even if ambient temperature is well above freezing.
Click to expand...
As far as I'm aware it's as standard. Mine can also be turned on at any ambient temperature that occurred this Summer. Only if the engine is substantially up to temperature will it not come on - I think (because it only happened once).
 
mitzimad said:
is it a cut of device or is it just the pickup pipe stop short of the bottom of the tank
Click to expand...
It is an electrical cutout switch and is actually mentioned in the MB manual under the full heater section which is where I found it. But is does not mention being fitted to my AUXILLIARY HEATER, it is obviously a fitment in the tank sender unit.

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@GWAYGWAY If the auxiliary heater on your MB is fitted like the VW ones (and if it's a Sprinter I don't see why not as it has close connections with the VW Crafter range) there is no technology in the cut-off for low fuel level, it's just the height of the pick-up pipe in the tank.
You may also find that there is a kit available to enable this heater to feed the cab heater matrix and run that either with or without the engine block heating with an optional remote control. I think that there is such a kit available for the VW T5 & T6 range although I believe it is from Webasto not VW. You may find some info via the VW T6 Forum.
 
If it has not got a level switch why did the light come on when I put the fuel in? No fuel by starvation would cause the unit to run dry and burn out the pump. No power in means a cutoff somewhere. The MB wiring is confusing enough with no available manuals for the punter, I have a MB manual on a memory stick but it is encrypted by a program You cannot get your hands on . Purposely done by the makers to keep the main dealers happy.
 
GWAYGWAY said:
If it has not got a level switch why did the light come on when I put the fuel in? No fuel by starvation would cause the unit to run dry and burn out the pump. No power in means a cutoff somewhere. The MB wiring is confusing enough with no available manuals for the punter, I have a MB manual on a memory stick but it is encrypted by a program You cannot get your hands on . Purposely done by the makers to keep the main dealers happy.
Click to expand...
i suspect it is just a short pick up pipe and it locks out as it can't ignite
 
Last edited:
mitzimad said:
i suspect it is just a short pick up pipe and it locks out as it can't ignite
Click to expand...
If it was then it would not start again when the fuel was at a level,, it is certainly a cutoff somewhere as without changing anything the light magically appears again.
 
GWAYGWAY said:
No fuel by starvation would cause the unit to run dry and burn out the pump.
Click to expand...
The pump is actually the fuel metering device. The heater pulses the pump at a rate determined by the amount of heat needed. I'd imagine that lack of fuel might not cause the unit to lock out - maybe it continues to pulse the pump intermittently until it sees fuel.

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