# Eberspacher Combitronic / Autocruise / Frost setting



## ingram

2006 Autocruise Starblazer. Combitronic Diesel / Electric, water heater and blown air room heater with 'De-Luxe' digital control panel.

This has a 'Frost' setting. The Eberspacher documents have conflicting information and I wonder if anyone *knows* when it operates.

When 'frost' is selected, one document says that the Combi room heating comes on when the internal 'van temperature drops to 0c and goes off when it reaches 5c.

The water will be heated periodically to prevent freezing.

The other document says that it will come on when the internal temp. drops to 5c and will go off at 15c. This is supported by the information in the Autocruise handbook; but that is only a copy of the Eber. book anyway.

Anyone *know*? I will e-mail Eberspacher but I know some of you like a challenge and I needed something sedentary to do while my wife is digging the garden  

Harvey


----------



## DABurleigh

Harvey,

My guess would be the "other" one (5-15C) was an old error in the manual, now corrected.

A frost thermostat range of 0-5C is intuitively correct and similar to other appliances with a frost setting.

Dave


----------



## ingram

DABurleigh said:


> Harvey,
> 
> My guess would be the "other" one (5-15C) was an old error in the manual, now corrected.
> 
> A frost thermostat range of 0-5C is intuitively correct and similar to other appliances with a frost setting.
> 
> Dave


Thanks for that Dave: I was thinking that 0c *inside* means it will be colder outside and that is where the Combitronic / hot water tank is but raising the inside temp. to 15c seems rather unnecessary. I have e-mailed Espar and Krueger ( Eberspacher dealers ) with the question and if I have any response I'll post here ... meanwhile any other input is welcome.

Harvey


----------



## TR5

Hi Harvey

The combitronic frostat setting turns on the heating at 5c and off at 15c.
It also turns on the water heating periodically.
It will operate on mains or diesel, whatever you have set the heating and hot water modes to, on the combitronic panel.

For normal use:-
If you set the heating mode to diesel, this will automatically heat the water also, (you may find the hot water select button illuminates on the panel, even if not chosen), but not so in electric mode.

If you have any more queries, PM or email me. We had this system in our Starlet ll, and with all the initial problems, know the system well.

Michael


----------



## DABurleigh

Michael - in which case I'm sure Eberspacher would appreciate you pointing out the error in their only current online Combitronic manual:
http://eberspacher.com/support-and-downloads/technical-documents.html
http://eberspacher.com/downloads/technical-documents/combitronic_22297.pdf
Pg 10 and I note only works on mains, not diesel

And for Harvey, I wouldn't like my van winter domestic electricity bill if I had a Combitronic with such a frostat temperature range, so you might like to switch it off and buy a cheap oil-fired radiator with frostat!

I can understand that Eberspacher may have changed the way Combitronic frost setting works through experience, but I can't understand in that case why a 2006 MH has conflicting documentation.

Dave


----------



## ingram

Michael,

The online manual that Dave has pointed to also states that the 'frost' setting *only* works on 230v; other manual I have says it will use diesel if 230v is not available .......... it's good isn't it? I have sussed out all other aspects of running this system now: just this frost setting anomaly to get sorted.

Dave,

As my house is heated by *oil* maybe we should live in the 'van on the drive for the winter ..... much smaller space to heat whatever the fuel ...... well anyway, maybe I will sit in it overnight with my coat on, when the weather gets colder and see just what it does do  

Harvey


----------



## TR5

Hi Harvey & Dave,

It is confusing, isn't it.  
I can only quote from the photocopy of operating instructions which I had with the motorhome, which conflicts with the eberspacher on-site manual that is now available. This went with the motorhome last week.

Maybe this will throw some light:- 

I had to have THREE ECU's fitted to mine, the first was fitted by an Eberspacher agent as a resolve to a problem (but it wasn't), it was replaced by Marquis as they thought it was faulty (but it wasn't - and this was an later version, which changed some settings), and then Eberspacher fitted the latest ECU unit when sorting other problems, which again changed settings, including maximum temperature ranges, combined heating (diesel and electric) terminology from "Auto" to "Boost" - so just maybe the frostat range has changed as well! 

I can't remember the lowest temperature you can set the heating to, but if this is around 5c you can always "dump" the contents of the water heater, and set the heating only to electric at, say 5c to protect the van, and leave it on.
I found on frostat that the water heater was on for too long, the water was always piping hot, so wasting electric.

From experience of two Autocruise's, their handbooks in relation to fitted equipment tends to be rather sparse, to say the least!

Michael


----------



## ingram

Having now examined more closely the documents that I have:

1) A photocopy of the one now available as a pdf from Eberspacher website. ( undated but obviously 'current' ) which gives the 0c and 5c figures.

2) A photocopy of an Eberspacher quick reference guide dated 2004. This is the one that gives the 5c and 15c figures which are also repeated in the Autocruise handbook; undated but supplied with the 2006 'van.

So: '2' was an earlier spec. ( or mistake ) and included in the Autocruise manual which was not updated by Autocruise when Eberspacher changed the spec. That's my theory anyway.

It still doesn't confirm what is actually in my 'van so will be testing it; just need some cold weather now.

I don't want to drain the tanks and pipework as I want to be able to use the 'van at short notice and don't want to drain it all down and then have to fill it again: I'd rather use the frost setting which seems to be a much better idea than having an auto dump valve as on some systems.

Thanks chaps, for the input ......... keep warm :wink: 

Harvey


----------



## TR5

Hi Harvey,

When you select the heating mode, what are the options:-

Original ECU <diesel> <230v> <auto>

Latest ECU <diesel> <230v> <boost>

Also the temperature range changed. I think (not exactly sure) that on the latest ECU the maximum temperature is 35c, whereas the original was 40c or 45c.

This will give you an idea if you have the older type ECU or the latest type. How many updates there are, I do not know, but I think it is at least three.

The ECU is a small blue coloured box which will be located in the area of the fan matrix / expansion bottle, with a multi-plug of wires entering it. some have date stamps and other information printed on them, which may also give an indication to the version.

I never drained mine down, but used the frostat initially, but later set the heating only on 230v at a low temperature, and lifted the cushions covering the chlorifier hot water unit. My fresh tank on the starlet ll (starburst) was in-board, though. It was later found that Marquis had not re-connected the thermostat for the hot water tank properly when messing about trying to rectify faults, so I don't know if mine worked properly with regard to the frostat on the hot water.

It may cost a few bob to leave the heating on, but at what cost a burst inaccessable pipe!

I leave a fan heater in the new one on about 6c - 8c, but drain the fresh tank, as I no longer have the combtronic unit. 

Best of luck,

Michael


----------



## ingram

Very helpful Michael.

Mine has the 'Boost' option and max. temperature of 35C. I had another look at the blue ECU case ( not easy to see on mine ) and found a date 'April 2006'. This also helps confirm that my 'van, first registered August 2006 really is a 2006 build.

It has been set on 'frost' for a few days. The current inside temperature on the Combitronic display is 10c. The heating is not on / blowing, but the water in the tank is *hot*!

My other van; the Renault Master Spectra has water in it, no heating on and is fine.

I may be having a rethink about using this 'frost' setting .........

Harvey


----------



## TR5

Hi Harvey,

Just set the heating to 230v, press the heating button and "arrow down" the stat temperature to the lowest option above 0c.
You don't need the water heating on, as the van will remain above freezing, the hot tank will not freeze. You could lift the cushions to improve circulation around the van, but I suspect, as was in my Starlet ll that your heater/fan matrix is under the same bench seat as the hot water tank, in which case it will get warm anyway.

You have the underslung tank I believe, like mine now, so may be wise to empty this if the weather gets excessively cold.

Michael.


----------



## ingram

The thot plickens, Michael.

I am fast coming to the conclusion that the old Autocruise company fitted as many different variations of heating / hot water systems as they possibly could. 8O 

Your Starburst, your Starblazer and my Starblazer all, it seems, have different systems.

My Starblazer does not have a water tank inside the 'van. The only parts of the Combitronic under the seat are the coolant container and the e.c.u. and wiring and some hoses.

It has become apparent from my research that my Combitronic is a 'Compact' unit not a 'Modular' system as some are. The information on the 'Compact' is rather sparse but it seems that the hot water tank is contained within the unit and the whole shebang is mounted under the floor; so my hot water tank will not benefit from heating the inside of the 'van by means other than running the Combi. itself!

Onwards and upwards ............. 

Harvey


----------



## Zebedee

You have a PM Harvey.


----------



## TR5

Hi Harvey,

If you look on the Eberspacher website, you will see the combitronic set-up uses the hydronic heating unit, which is a wet system, and heats water in a cylinder via an indirect coil. You should have a hot water tank, which also has an electric element to heat the water via 230v, and an expansion tank to feed the indirect coil circuit, which is filled with water and antifreeze. This works similar to a domestic system. You will have a fan matrix to distribute the hot air, which contains a heat exchanger running off the indirect system, and also contains a 230v element, so you can heat the habitation area by mains.
The option on your habitation heating <boost> turns on both diesel and electric heating for fast warm-up.

Question: When you select <diesel> as your habitation heating option and then press the top left button to turn on the hab. heating, does the water heating led on the panel (next to it - top right) light up?

I assume you have the 230v option via the combitronic control panel to heat water, in which case you MUST have a hot water cylinder installed somewhere in (or under) the van.
Your "coolant container" I assume is the wet system expansion bottle, which again confirms the wet system,as above.
In which case, your hot water tank AND fan matrix must be under the floor, in which case water in the hot tank needs protecting or draining when it goes below freezing.

My system in the Starblazer uses the D4 unit, which is just an air heater, with no option to use 230v, and does not heat the water. I have an entirely separate water storage boiler for water heating by Truma, which operates via a 230v element or gas.

Michael


----------



## DABurleigh

Well you lot have confused me 

Michael has ably described my system. The only thing is, I would bet my last £ I don't have a Combitronic 

Dave


----------



## TR5

Hi Dave,

The combitronic is probably better described as the eberspacher control panel used in conjunction with the hydronic wet system heater...etc...

Eberspacher also have various other control units which possibly could be used in various combinations with their heating/hot water systems.

Maybe you have a different manufactured unit. I'm sure there are others out there, or maybe you have a different controller (which is not called a combitronic).

For motorhomes at least, Eberspacher appear to have two main heating units, the "D" series which is a dry system with no facility for water heating, and the hydronic series which is the wet system. There are various control units, from very basic rotary thermostats, to all singing and dancing digital do-it-all units. I do know on my dry system there are several options listed, and this is probably the same for the wet system, so you could have the same system, but with a different control unit.
Even the combitronic has two versions!

Michael.


----------



## DABurleigh

This is my 3.5 year old Eberspacher Hydronic system:










though I maintain it is inaccurate in that the fresh water doesn't flow through the Hydronic unit, rather antifreeze-protected water does, which just goes to the fan matrix heat exchanger and the inner coil in the calorifier.

This, however, is what I thought an Eberspacher Combitronic was:










If Eberspacher now call BOTH of them Combitronic then the confusion is justifiably left at their door, especially if the only reference to Combitronic on their own website is the operating guide I referenced earlier in this thread!

I just hope those with the Combitronic outboard are provided with foolproof frost protection without crudely doing it by generating normal room temperatures inside!

Dave


----------



## ingram

Hi you two; now we are getting somewhere: I was about to post this website: a dealer called Automotive Electrical:

http://www.automotive-electrical.co.uk/eberspacher/combitronicairan

depicted, is what Dave has posted and yes: they are both referred to as Combitronic but Michaels explanation of the controls may explain that correctly ......... and I believe mine to be the 'Self Contained' or 'Compact' as in Dave's second picture. It does have a fan, of course and a 240v option for both the heating and hot water.

Michael, you asked: " Question: When you select <diesel> as your habitation heating option and then press the top left button to turn on the hab. heating, does the water heating led on the panel (next to it - top right) light up? "

I can't answer that just now but will check it out.

( This still doesn't answer my original question about the 'frost' setting but I think we have moved on a bit from there  )

I think that the system like mine may be discontinued because there is very little mention of it anywhere: maybe I have the only one in existence 

Harvey


----------



## TR5

Hi Dave

The first diagram is correct. As you say, the water is not fresh but from an expansion tank with antifreeze added. The tank shown in the drawing is the expansion tank, and not the fresh water tank - confusing I know.

If you go to:-
http://www.eberspacher.com/downloads/technical-documents/combitronic_22297.pdf

and look at the pics, you will see the combitronic control panel and the hydronic wet system heater in the same brochure.

The heater unit is the hydronic, the system is the combitronic, defined by the control panel used to operate the system.
It can also be used as a complete wet system central heating unit, like the Aldi heater (which is gas). There is not a combitronic boiler, just a combitronic system using the hydronic boiler.

Michael


----------



## ingram

TR5 said:


> Hi Dave
> 
> and look at the pics, you will see the combitronic control panel and the hydronic wet system heater in the same brochure.
> 
> Michael


You may also notice the model numbers. For example :--

CT05C, mine and CT05M, everyone else's! ( Compact and Modular ).... and a 'D' suffix denoting 'De Luxe' which has the 240v in addition to diesel.

btw I haven't been able to establish if mine is an '05' or an '03' as there is no model number anywhere to be seen: maybe that is on the actual unit under the van inside it's protective housing ....

Harvey


----------



## TR5

Hi Harvey,

There are two systems as I understand it, using the Hydronic boiler.

One is operated like a domestic combi boiler, supplying hot directly to taps on demand, the other is using a chlorifier with indirect heating. 

I would be surprised if you do not have any storage tank for hot water, otherwise how would it work on mains? I guess you have a chlorifier hidden somewhere!

If you run your diesel heating for say 10 - 15 minutes, turn it off, wait for a while, and then run the hot tap. If you have copious hot water, you definately have a chlorifier somewhere. If it runs cold very quickly, then it operates like a combi, but I have no idea how this would work on mains!

You say your not sure which model you have. With both of my vehicle's I have the installation certificate for the heating system, which tell's you what unit is fitted, when it was fitted and tested, and the serial number, etc.. - do you not have this?

Michael.


----------



## ingram

TR5 said:


> Hi Harvey,
> I would be surprised if you do not have any storage tank for hot water, otherwise how would it work on mains? I guess you have a chlorifier hidden somewhere!
> 
> You say your not sure which model you have. With both of my vehicle's I have the installation certificate for the heating system, which tell's you what unit is fitted, when it was fitted and tested, and the serial number, etc.. - do you not have this?
> 
> Michael.


Michael,

The hot tank and calorifier are contained in the housing, under the floor which also has the Hydronic unit in it as in the lower of Dave's two pictures. The fact that it is all housed in the one unit is why it is referred to as 'Compact', as opposed to 'Modular'. You will see in Dave's pictures that the 'unit' is altogether bigger than just the Hydronic shown in the top picture and has the blue cold supply and red hot outlet hose going into and out of it. This is how I understand it after reading everything I can find on it ............

Good tip about the install document. Found it and it is stated as being a 'D5W' which is obviously the actual 'Hydronic' model so this will equate to a Combitronic number CT05CD.

CT05 = Combitronic 5kw

C = Compact

D = deluxe control panel with 240v option.

btw the dealer's website that I posted previously:

http://www.eberspacher.com/downloads/technical-documents/combitronic_22297.pdf

has a price list and this shows that the 'Compact' system is for OEM supply / fitting only and so is not available retail which may explain the lack of information on it.

I definitely have a hot water tank; if I heat the water at night and turn it off it is still hot in the morning.

May get under one day and get the housing covers off and see exactly what is in there: photo's will be posted; but it may be some time away. 

Oh! and the forecast is for very cold Fr. and Sat. night so may be out there monitoring the 'frost setting' performance .........

Harvey


----------



## DABurleigh

Harvey,

I'd give Eberspacher at Ringwood (I think) a ring today, in view of the cold weather arriving. 

Sensor is needed where it might freeze, then either dump the water automatically or heat it automatically.

Sensor where it is much warmer inside, daft.

Dave


----------



## ingram

ingram said:


> Thanks for that Dave: I was thinking that 0c *inside* means it will be colder outside and that is where the Combitronic / hot water tank is but raising the inside temp. to 15c seems rather unnecessary. I have e-mailed Espar and Krueger ( Eberspacher dealers ) with the question and if I have any response I'll post here ... meanwhile any other input is welcome.
> 
> Harvey


Well, a good result.

I received a reply yesterday from Espar at Plymouth. They had asked my question of EBUK and then passed their reply on to me. It was more comprehensive than I had hoped for and here are the most relevant bits to our discussion. I also mentioned in my e-mail, that I didn't know exactly what the model of my Combitronic was which presumably resulted in the explanation of the model types: very useful and confirms what we have been discussing.

"The frost protection, which only operates with mains 230v hook up connected, will cut in at approx 0 degrees Celsius and will operate to approx 5 degrees Celsius. This temperature is sensed at the Combitronic panel."

"The immersion element is switched on for approx 5 minutes of operation within a 1 hour frost protect heating period.

"The heater fitted is either a CT03 CD or a CT03 MD. The M stands for Modular and the C for Compact - Modular has the fan blower and hot water tank (calorifier) inside under the seat locker and the Compact is the blower, calorifier, heater etc all in a big black box underneath the vehicle."

Note:- I think that mine is a CT05 CD but I have now asked for confirmation of that from the information on my installation document.

So, Dave, it seems that the system in your Murvi *is* in effect a 'Combitronic' 'Modular' .

Do you have the 'De Luxe' digital control panel and 240v operation in yours, and therefore , presumably the 'frost' setting?

Harvey


----------



## DABurleigh

No, I have no frost setting on mine, which is modular with calorifier inside but at 3.5 years old predated the Combitronic name. This meaage is from my phone but when I get home I'll take a pic of the panel or find one on the web.

You still need to get them to explain how your frost setting is supposed to work in practice when at 0 deg at the panel it could EASILY by minus 6 at the external calorifier!

For frost protection I don't bother draining the internal calorifier but have an oil-filled rad with frostat.

Dave


----------



## ingram

DABurleigh said:


> You still need to get them to explain how your frost setting is supposed to work in practice when at 0 deg at the panel it could EASILY by minus 6 at the external calorifier!
> 
> Dave


I agree that that doesn't seem very eficient but I don't think that'd get me anything really Dave.

I wanted to clarify how mine worked and confirm it was a 'Compact' and where all the bits including the calorifier are and Espar / Eberspacher have done that.

I think that at least three of us know a bit more about Eberspacher systems than we did a few days ago. 

btw the 'Espar' Canadian website has quite a few downloads which may be of interest even if not all of them of actual use to us.

Harvey


----------



## TR5

Hi Harvey,

Personally, I would set the combitronic panel to "heating on" with the mode set to 230v, and turn down the temperature setting inside the m/h to, say about 5c. With the compact having the chlorifier "within the same box" as the hydronic heater unit, the latent heat from this will keep the inside of the box relatively warm, whenever it needs to come on.
Providing you have no other heating within the m/h which will stop the combitronic heating from activating at this temp., I would think this should protect both the pipework and the hot tank/chlorifier. (However, depending on how it has been set, the temp. range may not go down this far on the combitronic panel - you will have to check.)

If you are worried this may not be enough, why not set it at 10c, then when it gets cold enough to activate, draw off some hot tank water and check the temp. You can then adjust the temp to suit, depending on the results.

Alternatively, speak to Jon Jennings, Eberspacher technical rep. on 01425 480151 - he is very helpful, and knows most m/h installations back to front, especially Autocruise ones. He may suggest (and tell you how) to get into engineers mode, where I would think you can alter any settings you wish. Then you could change the frostat settings to a more sensible range.

Hope this helps.


----------



## ingram

TR5 said:


> Hi Harvey,
> 
> Personally, I would set the combitronic panel to "heating on" with the mode set to 230v, and turn down the temperature setting inside the m/h to, say about 5c. With the compact having the chlorifier "within the same box" as the hydronic heater unit, the latent heat from this will keep the inside of the box relatively warm, whenever it needs to come on.
> Providing you have no other heating within the m/h which will stop the combitronic heating from activating at this temp., I would think this should protect both the pipework and the hot tank/chlorifier. (However, depending on how it has been set, the temp. range may not go down this far on the combitronic panel - you will have to check.)
> 
> If you are worried this may not be enough, why not set it at 10c, then when it gets cold enough to activate, draw off some hot tank water and check the temp. You can then adjust the temp to suit, depending on the results.
> 
> Alternatively, speak to Jon Jennings, Eberspacher technical rep. on 01425 480151 - he is very helpful, and knows most m/h installations back to front, especially Autocruise ones. He may suggest (and tell you how) to get into engineers mode, where I would think you can alter any settings you wish. Then you could change the frostat settings to a more sensible range.
> 
> Hope this helps.


Some good suggestions there Michael, thanks.

Thinking about it, it is strange that last week when I left it in 'Frost' mode for a couple or three days, over which time I am sure it didn't get *very* cold, I found the water to be hot when I tried it during the day ......... hmmmmmm ... actually, after all this, I may even just drain it all down: not thinking of going away before January now. We'll see.

Harvey


----------



## TR5

Hi Harvey

I am sure on my Starburst, when the frostat was on, the hot water heating came on periodically regrdless of whether heating was needed or not.
That's another rason for not using the frostat, but just set the heating to a low temp., which should protect the water side also.

Michael


----------



## DABurleigh

DABurleigh said:


> I'll take a pic of the panel


----------



## ingram

It looks as though you have a few toys to play with there Dave  .

Are both of the lower panels connected with the Eberspacher? Printing not quite focussed enough for me to read properly. I see you have 'engine heating' as part of your system I think.

Harvey


----------



## DABurleigh

Harvey,

No, just the one panel. Sorry about the focus - my photo, not your printer. It was quite dark in there, I was in a rush so didn't want to remove the sunshades, and I had to do it without flash which simply ruined it. So it was a 400ASA with camera shake warning IIRC .

Yes, the lovely part about Eberspacher heating is the integration with the van. Not shown is the remote control. Whether lying in bed in the house or away in the van in a nearby pub or whatever, I press a blipper on the keyfob and then when I get to the van it is all toasty, demisted and engine warm  Heating in the back on the move, hot water on tap as soon as you stop, etc.

Dave


----------

