John_Clarke
Well-Known Member
I have had the following email conversation with Eberspacher UK which may be of interest to other Eberspacher owners. They kindly agreed to me posting this conversation. I have edited out all but the technical content.
Email 1
I have an Airtronic D4 heater installed in a dry locker in my boat. The manual recommends running it once a month. I usually do not visit the boat much during the winter so it is hard to keep up this schedule. Also, in the summer it may be uncomfortable to run the heater at full output.
Please could you tell me what the possible consequences are of not running it monthly. How important is this?
Reply 1
Running the heater on a regular basis is required for two reasons, the first is to keep the little plunger in the fuel metering pump from sticking and the second is to keep the diesel fuel in the fuel lines fresh.
I would say, if your diesel is relatively clean and dry then two or three months should be possible. If you have copper fuel lines fitted you may find even this short period of time too long to have the heater start reliably first time. Unfortunately copper degrades modern diesel fuel at an alarming rate and as the boat safety scheme will not let us use any alternative we are where we are.
As for running your heater during the summer months, this can be safely done when no one is aboard, so if you are washing down, packing sails or having a swift half in the local etc. just pop the heater on for 15 minutes to refresh the lines and keep the pump active.
Email 2
I am considering installing an alternative paraffin feed to my heater to burn off carbon deposits. Would paraffin in the pump and copper pipe avoid the problems of the plunger sticking and degradation of the fuel?
Reply 2
Unfortunately due to miss information recently printed in the press paraffin or kerosene will not clean the carbon out of a heater. If you read the article in Practical Boat Owner, the photographs showed the inside of a truck heater that had run on clean EN590 specification diesel, most truck heaters look like that when you open them up.
Many marinas now supply the new ultra low sulphur gas oil (red diesel), if your marina is supplying this then paraffin would be a waste of time as far as keeping your heater clean was concerned, the new fuel is particularly clean burning. Also to comply with ISO 10088 regulations and or Boat safety Scheme, if you are estuary or inland based, your paraffin tank would have to be securely mounted with a clearly labelled deck filler and breather system, any hoses would have to conform to ISO 7840.
We have not tried long term testing with paraffin or kerosene to see if there is any improvement in the length of time a heater can be left for? However a fuel stabiliser with an anti-oxidant added to standard gas oil (red diesel) will help with longevity of fuel life.
If you must leave your heater for extended periods of time and the pump plunger does stick, sometimes it can be freed (unofficially) by a sharp tap on the pump body with an 11/16 or 17mm sized spanner (ideal size), please bear in mind though, if this trick does not work a new pump may cost in the region of £160.
Email 3
I am bit puzzled that you say that paraffin will not clean out the carbon – there is the following document on the American Espar site: http://www.espar.com/tech_manuals/AIRTRONIC%202-4/!Airtronic%20Flame%20Tube%20Carbon%20Removal.pdf which recommends the use of paraffin for removing carbon from the heater. Are they wrong and why would they have this document on their website?
I am using Marine 16 Diesel Fuel Maintenance which they state “brings stored fuel up to spec, uplifts cetane value plus 3 for easier starting. Prevents "diesel bug", continuous use will reduce fuel system deposits, gums and varnishes to zero giving cleaner burn, power restoration, fuel economy and prevents injector blocking.” There is no mention of it being an anti-oxidant but I will ask them.
Reply 3
I am unfortunately aware of the Espar page and yes it has caused us a few issues, you will also notice that no other Eberspacher website in the world makes a similar statement. This post has probably been taken somewhat out of context. Basically if a heater has had a short term fuelling issue or exhaust blockage for example and this scenario has produced soft, oily carbon deposits within the burner chamber and flame tube, then burning a very clean fuel such as paraffin or kerosene will turn that carbon to ash and the heater should then blow it out of the exhaust thus cleaning the heater. Please note the part of their statement that says “it may be possible to clean the burner”, not it is possible. You will see from the photographs halfway down the Espar document that this is the light fluffy form of carbon I have mentioned.
The type of hard baked on carbon that is usually found in heaters running on high sulphur marine gas oil (MGO) or standard gas oil (35 second heating oil) sold as marine red diesel, heaters running for many years without service or heaters running for excessive periods of time in low heat mode, then paraffin unfortunately won’t touch it.
Marine 16 seems to be a well-respected product although we have done no testing with it ourselves but they do offer a Diesel Fuel Stabiliser, this maybe a better product to use in your case?
Email 1
I have an Airtronic D4 heater installed in a dry locker in my boat. The manual recommends running it once a month. I usually do not visit the boat much during the winter so it is hard to keep up this schedule. Also, in the summer it may be uncomfortable to run the heater at full output.
Please could you tell me what the possible consequences are of not running it monthly. How important is this?
Reply 1
Running the heater on a regular basis is required for two reasons, the first is to keep the little plunger in the fuel metering pump from sticking and the second is to keep the diesel fuel in the fuel lines fresh.
I would say, if your diesel is relatively clean and dry then two or three months should be possible. If you have copper fuel lines fitted you may find even this short period of time too long to have the heater start reliably first time. Unfortunately copper degrades modern diesel fuel at an alarming rate and as the boat safety scheme will not let us use any alternative we are where we are.
As for running your heater during the summer months, this can be safely done when no one is aboard, so if you are washing down, packing sails or having a swift half in the local etc. just pop the heater on for 15 minutes to refresh the lines and keep the pump active.
Email 2
I am considering installing an alternative paraffin feed to my heater to burn off carbon deposits. Would paraffin in the pump and copper pipe avoid the problems of the plunger sticking and degradation of the fuel?
Reply 2
Unfortunately due to miss information recently printed in the press paraffin or kerosene will not clean the carbon out of a heater. If you read the article in Practical Boat Owner, the photographs showed the inside of a truck heater that had run on clean EN590 specification diesel, most truck heaters look like that when you open them up.
Many marinas now supply the new ultra low sulphur gas oil (red diesel), if your marina is supplying this then paraffin would be a waste of time as far as keeping your heater clean was concerned, the new fuel is particularly clean burning. Also to comply with ISO 10088 regulations and or Boat safety Scheme, if you are estuary or inland based, your paraffin tank would have to be securely mounted with a clearly labelled deck filler and breather system, any hoses would have to conform to ISO 7840.
We have not tried long term testing with paraffin or kerosene to see if there is any improvement in the length of time a heater can be left for? However a fuel stabiliser with an anti-oxidant added to standard gas oil (red diesel) will help with longevity of fuel life.
If you must leave your heater for extended periods of time and the pump plunger does stick, sometimes it can be freed (unofficially) by a sharp tap on the pump body with an 11/16 or 17mm sized spanner (ideal size), please bear in mind though, if this trick does not work a new pump may cost in the region of £160.
Email 3
I am bit puzzled that you say that paraffin will not clean out the carbon – there is the following document on the American Espar site: http://www.espar.com/tech_manuals/AIRTRONIC%202-4/!Airtronic%20Flame%20Tube%20Carbon%20Removal.pdf which recommends the use of paraffin for removing carbon from the heater. Are they wrong and why would they have this document on their website?
I am using Marine 16 Diesel Fuel Maintenance which they state “brings stored fuel up to spec, uplifts cetane value plus 3 for easier starting. Prevents "diesel bug", continuous use will reduce fuel system deposits, gums and varnishes to zero giving cleaner burn, power restoration, fuel economy and prevents injector blocking.” There is no mention of it being an anti-oxidant but I will ask them.
Reply 3
I am unfortunately aware of the Espar page and yes it has caused us a few issues, you will also notice that no other Eberspacher website in the world makes a similar statement. This post has probably been taken somewhat out of context. Basically if a heater has had a short term fuelling issue or exhaust blockage for example and this scenario has produced soft, oily carbon deposits within the burner chamber and flame tube, then burning a very clean fuel such as paraffin or kerosene will turn that carbon to ash and the heater should then blow it out of the exhaust thus cleaning the heater. Please note the part of their statement that says “it may be possible to clean the burner”, not it is possible. You will see from the photographs halfway down the Espar document that this is the light fluffy form of carbon I have mentioned.
The type of hard baked on carbon that is usually found in heaters running on high sulphur marine gas oil (MGO) or standard gas oil (35 second heating oil) sold as marine red diesel, heaters running for many years without service or heaters running for excessive periods of time in low heat mode, then paraffin unfortunately won’t touch it.
Marine 16 seems to be a well-respected product although we have done no testing with it ourselves but they do offer a Diesel Fuel Stabiliser, this maybe a better product to use in your case?
