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Buying a second hand Eberspacher  -  Advice and Warnings.
Non standard heaters.
A small number of heaters suffer from corroded ports, we don't know the history of these to find the reasons.
We suspect it is due to galvanic corrosion between the alloy port and the stainless steel pipe.
A very badly corroded exhaust port could require a new heat exchanger.
We are currently investigating a couple of repair methods, at an early stage at the moment, more details once we try them out.
Contact us if required.
What sized heater?
Eberspacher model naming is confusing.
Older models had a naming convention, newer models do not follow this system.
First Letter - D diesel, B petrol. 
Number generally represents heat output, higher number higher output
Letter - L air,  W water.  Older models only, newer models do not use this convention and use L for Large.
Any letters following identify the model, eg D1L,  D1LC,  D1LCC.
Air Heater models
They were manufactured in the order D1L,  D1LC,  D1LCC, with Airtronic D2 being the current model.
Similarly for higher heat models        D3L,  D3LC,  D3LCC, with Airtronic D4 being the current model. (Airtronic D3 is not sold in UK)
                                                     D4L,   D5L,    D5LC,   with Airtronic D5 being the current model.
The Air Heater Models pages contain information on Eberspacher models.

Water heater models
Oldest models          D4W (not sold in UK), D5W, D7W, D9W, D10W.
Hydronic older          D3WZ, D4WZ, D5WZ   (OEM specific heaters with no water pump, do not buy these.)
Hydronic current       D4WS (24v), D4WSC (12v), D5WS (24v), D5WSC (12v)
Hydronic M I            D10W
Hydronic M II (2013) M8, M10, M12,
Hydronic L I             L16, L24, L30, L35
Hydronic L II            LII16, LII24, LII30, LII35

Stating the obvious, when identifying models always look at the label.
Labels show 3 consecutive years, eg 01 02 03.  All you can tell is the heater was made in 2001, possibly earlier, and probably first installed in 2001, 2002 or 2003.

Buying Page 2  contains extra information on some of the ancillary items to go with the heater.

Be very careful identifying models.
We are noticing an increasing number of non standard Eberspacher heaters removed from modern vehicles on offer, they have modified ECUs and many will not work without the vehicle. (see below)
We know of a number of buyers who have purchased a D1L model instead of the D1LCC they actually wanted. Photos on ebay are sometimes taken to partially conceal the external ECU and relays, often by placing them among the controller and cables so they are not very obvious.
That bargain price may not be such a good bargain after all.
New heaters sold from Turkey are said to be OEM versions and are not supported by Eberspacher UK.

Look very closely at what is being sold.
Eberspacher air models require a pump, controller and wiring loom, many are removed from vehicles without these and sold without them, the pump could cost another 75, wiring loom 45, controller 40.
Water heaters usually also require a water pump. Some water heaters have the fuel pumps built in.
Heaters and pumps are made in 12 and 24 volt versions, check before buying.
Pumps are specific to the heater type, see the fuel pages for details.
If you do have to buy a new controller get one with diagnostics readout, invaluable when fault finding.
Items such as inlet & exhaust pipe, fuel pipe, air ducting and battery wiring will be specific to your installation. (see next page)

"Working"  Eberpacher air heaters are not cheap so you may be tempted to try buying others, usually not a good choice.
Unlike many items sold on ebay you are unlikely to find any with simple cheap to solve faults because of the following points.
Eberspacher owners are not like many typical ebay sellers who will update every couple of years to the latest model or as soon as anything gives a problem. Many heaters will have been fitted in trucks, if the engine has to be run to keep warm the truck uses a lot more fuel than an Eberspacher so it is cheaper to fix the Eberspacher.
Boat owners congregate in marinas or harbours, inevitably there will be someone there who knows something about Eberspachers and also knows they need regular servicing together with details of dealers.
Inside the heater, apart from needing annual service there is little to go wrong and when it does it is normally the expensive ECU.
On older model heaters the glowpin often fails but it is easy to remove and visually check and replace so it will normally be fixed.
So simpler faults are usually sorted out before selling, the detailed advice given on our site has also reduced the chances of a cheap fixable bargain!

"Working when removed from vehicle". Testing would increase the selling price so why didn't they test it before selling.
Don't assume it was removed recently or that it is has everything needed to run.
Warning: Make sure you read the non standard heater section below, if you buy one of these you will make an expensive mistake.
A good seller should accept returns if it is untested, check before purchase.
Always bench test the heater as soon as it is received, it is also easier to sort out on the bench than when installed on the boat.

"Believed to be working when removed" or wording in a similar vein, usually phrased to lead you to think it will probably work so worth buying. Some are said to have been tucked away in a garage or shed for a few years. Usually sold without the bits needed to test as soon as it is received so testing may be done months later. Generally a no guarantee or return allowed listing. If it means making money many sellers will deliberately mislead, unethical but we see lots of examples of it.
Don't be gullible, treat it like the next category.

"Unable to test so selling as spares or repair".  This is often used to conceal serious problems, in reality it usually means  "I know its faulty but if I said so it would go for a very low price".  Most will be faulty, usually with ECU faults and if you buy one you will not be able to return it as it is as described. A new ECU costs over 250 so you could easily end up paying almost the same price for a used heater as a new one.

Water heaters  
Corrosion and motor problems are higher than with air models. Advice from experienced users would be welcome for inclusion.
Do not buy a heater with a Z in the model name, these are OEM heaters as shown below. They are not supported by Eberspacher or their dealers. The Hydronic II D5WZ does not have manuals so no wiring diagrams available.
There is no cheap conversion method to change voltage inside the heater so check before purchasing.
However it is possible to use voltage converters to change 12V dc to 24V dc  or 24V dc to 12V dc.
Operationally I have reservations about the use of converters and would prefer not to use one myself but they can work. Switching on the heater before the converter can cause problems for the ECU, sometimes it can be recovered ok but not always. The heater must be allowed to go through its 4 minute shut down cycle before switching off the converter. That inevitably means switching off the converter will be overlooked, the converter continues to draw some current all the time it is on.

Converters are not as convenient and take more current from the battery than using a correct voltage Eberspacher. For those unfamiliar with electronics a bit more explanation on this point. A 12V Airtronic D2 takes a maximum of about 10 amps, a 24V Airtronic D2 takes about 5 amps. The 24V version's 5 amps may look better but in fact it is exactly the same amount of power.
When a voltage converter is used it changes the voltage from 12 to 24 volts, the current drawn by a 24 volt Eberspacher D2 is about 5 amps, the current drawn by the converter from the 12 volt battery will in theory be double that at about 10 amps which is the same as a 12 volt D2. In practice converters are not 100% efficient so actual current drawn at 12V will be significantly more than that figure. A major problem would be if the converter has insufficient smoothing. This could result in the Eberspacher not working properly even though the current rating is sufficient.
I have no practical experience of using either type of high current converter so my concerns are purely theoretical. I do know of one user who is running a 24v heater with a 12v converter without problems and another who had problems so replaced the heater.

Ebay had a listing in Feb 2012 for a DC 12V to 24V 10A 240W Step-Up Power DC-DC Converter for 32.85
That 10 amp rating is for the 24 volt output and is sufficient only for a D2 or D4, not for other air heaters which need a higher rating.
In April 2014 an ebay search for 24v to 12v converters gave lower prices than the same devices searched for with 24v to 12v droppers.
A 30 amp max 24V to 12V converter was about 4.50
These two examples just illustrate prices, No information is given on smoothing and no guarantee they would work without problems.
An ebay sellers listing, nothing untrue but the telltale ECU plug not shown and no mention of non standard.
I leave you to draw your own conclusions on this one!
"Eberspacher D4 ECU    
Removed from a Man truck had a broken plug so unpinned ready to fit another new it was fully working before removing plug, they are expensive to buy, could come in handy as a spare one."
Labels on two Hydronics sold as removed from Renault trucks.
Note the Renault name at bottom.
Buying a heater.
Buying Advice page 2 continues with ancillary parts.
Why buy an Eberspacher heater?
Eberspacher (Espar in America & Canada) heaters are mainly used in vehicles to supply heat when they are stationary.
They are also fitted in boats and caravans. They can run on the vehicle or boats fuel supply.
We use Eberspachers in our vans and Dereks caravan and for us they are the best and cheapest form of portable heating.

What are the alternatives?
Running the engine when stationary uses a great deal of fuel.
LPG heaters need heavy gas cylinders and are very expensive to run compared to diesel heaters.
It is difficult to gauge when they will run out and gas leaks can be explosive.
LPG when burnt produces carbon monoxide which can kill.
Eberpachers exhaust gasses should be avoided but CO levels are low, there have been no recorded deaths.
Solar and wind power do not give enough heat.
Alternative diesel heater manufacturers have no equivalent website to ours for free advice on servicing and repairs.
There is a well known law that says they always fail when you are at least 100 miles from your nearest dealer who is of course closed for the evening or weekend.


Some Eberspachers are manufactured with modified ECUs so the heater can be controlled by the vehicles engine management system, they are not switched on and off in the normal way so cannot be made to work with simple wiring changes.
Usually these will be described as removed from ***** vehicle.
Sometimes they will be sold as "Working when removed from vehicle", that may be true but many wont work away from it!
DO NOT BUY any of these non standard versions for normal use, you will be wasting money.
Most will not work on their own without replacing the ECU which costs 250 to 350!

Also some controllers have been modified to work with the engine management system and wont work away from it. (see next page)
Non standard air heaters often have a different connector and non standard colours, the labels are a good warning.
Scania, Mann, Mercedes, Iveco, Renault, Daf are  truck manufacturers who fit modified heaters but there are probably others.
These are mainly Airtronics D2 D4 models but we know a few D1LCC are included.
Any water heaters with the letter Z  such as D3WZ, D5WZ are OEM heaters, most will be non standard so do not buy.

Specific non standard ECU information
A reliable source has advised us that a DAF D2 ECU  Part number 22 5102 00 14 01    DAF1455175 bought on ebay had the normal plug and works as a standard unit.
However another DAF ECU 22 5102 00 34 01 DAF: 1665022 has a different connector and is non standard.
Scania ECU 22 5102 00 11 01 0C is confirmed as definitely not a standard unit.
We are also aware of one non standard 24v D4 model from a truck manufacturer that has an ECU modified to use older 1-3kw pumps.
If this is used with a standard 1-4kw pump it overheats badly.
Eberspacher heaters are very safe provided they are properly installed by a dealer.
This website is designed to cover their maintenance and repair.
It is NOT designed as an installation guide and we do not cover most installation details.
We know that despite our advice to use a dealer some users will inevitably install it themselves.
You do this at your own risk, we accept no responsibly for DIY installations.
Read the manuals carefully and follow the Eberspacher or Espar guidelines to ensure it works properly and is safe.
Boat installations must also comply with the relevant regulations.
Bad installations can be dangerous and could invalidate insurance.
Sailing boat
Motor boat
Narrow boat
Airtronic D2
13 - 32'
13 - 22'

Airtronic D4 Plus
26 - 29'
22 - 32'

Airtronic D5
39 - 49'
32 - 45'

49 - 62'
45 - 50'

Hydronic 4
19 - 29'
19 - 29'
42 - 59'
Hydronic 5
19 - 42'
19 - 42'
55 - 72'
Hydronic II M10
32 - 49'
32 - 49'

Hydronic II M12
39 - 55'
39 - 55'

Hydronic II L16
55 - 68'
55 - 68'

Hydronic II L25/L30/L35
65 - 72'
65 - 72'

Sizing depends on insulation etc as well as level of heat required, some just require background heat others want it like a sauna. We have a D2 or a D1LCC in our Transit vans and a caravan. Dealers should be able to give more advice. A general rule of thumb is 120 to 200 watts per cubic metre. Alternatively you could try a mains fan heater to see how much heat is needed.
A D4 Plus has a more powerful fan than a D4 so can have longer air ducting.
Bigger is not always better, an oversized heater will run on low or standby most of the time, needing more frequent servicing.
The following information from Eberspacher gives a general starting point for boats, also talk to fellow boat owners.
Running a 24v heater from 12v supply or 12v heater from 24v supply.
Corroded exhaust ports.
This one is not good for getting a gas tight seal.
D1L exhaust port rotted away.
We hope to repair it later as a trial.