ljc Posted November 24, 2009 Share Posted November 24, 2009 We have a Burstner Argos 747 which is almost 2 years old. It has an auxiliary heat exchanger pump which uses the engine coolant. We have had a third one fitted today as the others leaked. Guess what? This one is leaking too! Anybody got any suggestions as to what we can do? It is a 100 mile round trip to the dealers and we have done this at least ten times over this pump and other problems, so we are well out of pocket. We have a five year guarantee on the motorhome. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 24, 2009 Share Posted November 24, 2009 I suggest you get in touch with Alde(UK). Contact details on: http://www.alde.co.uk/ That 3 pumps have leaked suggests there's something odd about the system installed in your Argos. Link to comment Share on other sites More sharing options...
Stuart Posted November 24, 2009 Share Posted November 24, 2009 I don't claim to know anything about this problem but it does occur to me that the pump is operating under radiator pressure and is of a design not intended for this application. Most circulating pumps will have no appreciable pressure in the system. Stuart Link to comment Share on other sites More sharing options...
747 Posted November 24, 2009 Share Posted November 24, 2009 Are you sure this is a pump? I have a 2003 Burstner Active 747-2 and it has the facility to heat up the cabin while travelling. The heater pipes to the cab heater have a tee piece which directs the hot water in the cooling system to a thermostatically controlled fan under the dinette seats. There is a 2 position switch for the fan to blow warm air when the thermostat opens. You may have a totally different system but if so, try to get it modified to the same as mine. I know that I would be extremely upset if I had the problems that you are having. If they cannot fix it then get it altered to something else. Your van is still under warranty so make a stink about it. Tell the dealer that you will name and shame him in public forums unless a solution is reached. You do not have to carry out that threat, just imply it. Best of luck. Link to comment Share on other sites More sharing options...
Guest peter Posted November 24, 2009 Share Posted November 24, 2009 bakersboy - 2009-11-24 9:10 PM I don't claim to know anything about this problem but it does occur to me that the pump is operating under radiator pressure and is of a design not intended for this application. Most circulating pumps will have no appreciable pressure in the system. StuartNot to mention that is is operating at near boiling point. Though I doubt whether that is the case as there is already a pump on that circuit, the engine pump. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 25, 2009 Share Posted November 25, 2009 As Lin (ljc) says, the 'wet' type of Alde central heating system used in motorhomes includes the option to add an engine-coolant heat exchanger. When the vehicle's motor is running, heated engine coolant passes through one side of this heat exchanger. The Alde heater has its own 12V circulation pump and, if this pump is switched on, it circulates the heater's 'heat transfer fluid' (HTF) - a 50:50 water/glycol mixture - through the other side of the heat exchanger. Heat transfers from the engine-coolant to the HTF, which in turn is circulated through radiators installed in the motorhome's living area. There is an additional option that allows the heat exchanger's function to be 'reversed', so that it can be used for engine heating by transferring heat from the HTF to the engine coolant. This option involves installing a 12V circulation pump (Part Number 2755 000 in my Alde catalogue) into the engine's cooling system between the Alde heat exchanger and the vehicle's motor. The Alde heater is switched on and heated HTF is circulated through one side of the heat exchanger. The 2755 circulation pump is switched on causing engine coolant to circulate through the other side of the heat exchanger and through the vehicle's motor. Heat transfers from the HTF to the engine coolant, thus warming up the motor. In Lin's case, I've assumed that it's the 2755 pump that has been leaking. As has already been observed, the 2755 circulation pump must be able to cope with the temperature and pressure found in a vehicle's cooling system (and it must also be installed so that the motor's thermostat does not interfere with coolant circulation). But it would be perverse to expect Alde to have failed to take this into account when specifying the 2755 pump's design. The Alde catalogue's description of the 2755 unit indicates that it's a simple centrifugal pump with permanent magnet motor and the picture of it suggests that it should be robust. I guess there is a (small) possibility of a batch of these pumps having a manufacturing fault, or that there's some vital process in the installation of the pump that, if not carried out correctly, will cause the pump to leak. Although Alde wet systems are not uncommon for motorhomes, I suspect that the heat exchanger + 2755-pump option is rare and, if there is something peculiar about this part of Lin's Argos's heating system, it's possible that the dealer won't recognise it. That's why I suggested advise be sought from Alde(UK). You can't necessarily rely on motorhome manufacturers' competence. I recall a Buccaneer motorhome with an Alde heater and heat exchanger option not being fitted with a shut-off valve for the heat exchanger. The owner said that the system was brilliant during the winter, but he realised something was wrong when warm weather arrived and the motorhome became a sauna. Lin: I'm a mite wary of your "We have a five year guarantee on the motorhome" comment, as this is an unusually long period for a motorhome warranty. My 2007 Burstner brochure specifies the guarantee as 5 years regarding water ingress (subject to annual inspection) and "at least 2 years manufacturers warranty". It's also sometimes the case that major items of motorhome equipment, like heaters and fridges, have their own warranty terms and conditions and a warranty duration different to that of the motorhome converter's guarantee. It may well be that your Argos has an all-embracing 5-year warranty and that this is confirmed by the vehicle's documentation, but (if there is any possibility of doubt) I know I'd want to check this out. Link to comment Share on other sites More sharing options...
ljc Posted November 25, 2009 Author Share Posted November 25, 2009 Thank you Derek. My husband Eric has now got onto head office for the agent we bought the motorhome from and we are hoping to make some progress. The five year 'guarantee' is actually a five year insurance we took out from the agent to cover all parts and labour. Link to comment Share on other sites More sharing options...
747 Posted November 25, 2009 Share Posted November 25, 2009 If it is of any help, there is currently a thread going on Motorhome facts about Alde heat exchangers. Some photos have been posted which may help. On this thread, they are talking about retrofitting a heat exchanger and if I have it right, no pump is needed. As Derek says, if you want the facility to run heating fluid through the engine to warm it up, a pump is required. What puzzles me however is the fact that Derek described a robust centrifugal pump (which is what you need) yet the Alde circulating pump for the heating system is a tiny little thing that sits on top of the expansion bottle in a cupboard. These 2 circuits will never be compatible if they are in the same circuit. I am maybe going a bit off thread here but if you want to depress yourself, then have a good read of your van warranty terms. In short, you need everything to go wrong in the first year because after that, there is very little that is covered. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 25, 2009 Share Posted November 25, 2009 747 - 2009-11-25 12:45 PM What puzzles me however is the fact that Derek described a robust centrifugal pump (which is what you need) yet the Alde circulating pump for the heating system is a tiny little thing that sits on top of the expansion bottle in a cupboard. These 2 circuits will never be compatible if they are in the same circuit. The two 'circuits' are separate, as one might expect where a heat-exchanger is involved. I thought this would have been apparent from my description. If you get hold of an Alde catalogue, there's a simple schematic that should clarify matters. Link to comment Share on other sites More sharing options...
747 Posted November 25, 2009 Share Posted November 25, 2009 As the system is operated by the engine circulating pump then there is no need for a second pump. As I said in an earlier posting that the retrofit parts did not include another pump for the system. The heat comes from the engine cooling system and the heat exchanger uses this heat. There is no extra pump in my system. If a second pump has been added then this may be to circulate hot water from the heating system back to the engine block. Again, this means a link between the systems. Perhaps this is an electrical wiring fault and a pump is working against the engine pump? I wish I lived closer because I have had 40+ years engineering experience and I should be able to suss it out. But without eyes on, I can only guess. Link to comment Share on other sites More sharing options...
davenewellhome Posted November 25, 2009 Share Posted November 25, 2009 747, Derek's post was quite clear, if the Alde heating is to be used to pre heat the engine then a circulating pump will need to be installed in the engine coolant circuit (Derek has even provided the Aldoe part number). The two circuits are always kept separate via the heat exchanger. The engine coolant circulation pump would only ever work "against" the engine driven pump if it were used when the engine was running and I would expect an electrical interlock to be in place to prevent that. D. Link to comment Share on other sites More sharing options...
747 Posted November 25, 2009 Share Posted November 25, 2009 Hi Dave, What is puzzling me is this: Engine hot water heats living space from engine coolant (which is hot) Living space heats engine (where does the hot liquid come from to heat the engine) It cannot come from the Alde heating system as its totally separate. The only way would be to pass it through the Alde boiler as it is the only heat source in the back of the van. I must be missing something here. Should I get my coat? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 26, 2009 Share Posted November 26, 2009 747 OK - let's try again. First of all forget the fan-assisted 'engine-coolant' heater fitted to your own Argos. This type of heater is commonplace on Continental motorhomes and is not a specific Alde option. Now read on... "The 'wet' type of Alde central heating system used in motorhomes includes the option to add an engine-coolant heat exchanger. When the vehicle's motor is running, heated engine coolant passes through one side of this heat exchanger. The Alde heater has its own 12V circulation pump and, if this pump is switched on, it circulates the heater's 'heat transfer fluid' (HTF) - a 50:50 water/glycol mixture - through the other side of the heat exchanger. Heat transfers from the engine-coolant to the HTF, which in turn is circulated through radiators installed in the motorhome's living area." This is the standard arrangement when an Alde 'engine-coolant' heat exchanger is added to an Alde central heating system. Imagine two separate circles, one representing the circulation of the HTF around the Alde central heating 'circuit' and the other representing the circulation of engine coolant around the 'circuit' involving the motorhome's engine, radiator and cab-heater matrix. Now move the circles towards each other until they touch. At the touching-point visualise a liquid-to-liquid heat exchanger being inserted. One side of the heat exchanger has the HTF circuit running through it and the other side of the exchanger has the engine coolant circuit running through it. The 'circuits' remain completely separate but, if the liquid in both circuits is circulated and one circuit's liquid is hotter than the other, then the heat exchanger will cause the hotter liquid to transfer heat to the colder liquid. The Alde heater's own 12V pump will circulate cold HTF through the Alde central heating system and the Alde heat exchanger. When the motorhome's motor is running hot engine coolant will be circulated around the vehicle's cooling system and through the Alde heat exchanger by the motor's own water pump. The hot engine coolant will heat the cold HTF that will, in turn, warm the motorhome's interior and heat the motorhome's 'domestic' water. With this option (as you rightly say) no further pump will be needed in the engine coolant 'circuit'. "There is an additional option that allows the heat exchanger's function to be 'reversed', so that it can be used for engine heating by transferring heat from the HTF to the engine coolant. This option involves installing a 12V circulation pump (Part Number 2755 000 in my Alde catalogue) into the engine's cooling system between the Alde heat exchanger and the vehicle's motor. The Alde heater is switched on and heated HTF is circulated through one side of the heat exchanger. The 2755 circulation pump is switched on causing engine coolant to circulate through the other side of the heat exchanger and through the vehicle's motor. Heat transfers from the HTF to the engine coolant, thus warming up the motor." This is a secondary Alde option that is unlikely to be as well known and understood as the simple adding-a-heat-exchanger one. As the option is intended to allow an Alde heater to warm up a non-running engine, a pump must be inserted in the engine coolant circuit to provide circulation of that coolant through the heat exchanger. This pump permits the hot HTF produced by an Alde heater and running through one side of the Alde heat exchanger to transfer heat to cold engine coolant being pumped through the Alde heat exchanger's other side. If no additional pump were to be fitted, with the vehicle's motor stopped there would be no engine-coolant circulation through the heat exchanger and, hence, no heating of the vehicle's motor. I've not seen a 2755 pump in the flesh, but (extrapolating from the photo in the Alde catalogue), it's about 18cm long with a diameter of around 4cm. According to the catalogue, the pump has a maximum flow rate of 15litres/min at 0.1bar and a motor output of 14W. Its design is straightforward with a cylindrical motor casing with a couple of electrical cables at the back and an impeller housing screwed on the casing's front. Logically, coolant leakage could be caused by a damaged impeller housing, a leak at the joint between housing and motor casing, or at the seal where the motor-shaft passes into the impeller housing. Obviously there could be leaks where the hoses containing the engine coolant are attached to the impeller housing, but, as Lin's dealer has seen fit to replace two motors, I'm minded to dismiss that idea. Clearly it's vital that the pump be suitably positioned within the engine-coolant circuit so that it does not restrict coolant circulation when the vehicle's motor is running. As I haven't got the appropriate Alde installation instructions, I've no idea if any fail-safe electrical interlock is necessary. I would guess that it shouldn't be as long as the pump is correctly fitted. A warning in the Alde catalogue states "When installing the heat exchanger, the manufacturer or importer should be consulted so that the engine is not damaged". As Burstner will have had plenty of experience of Alde heating systems and it's likely that Lin's dealership is also familiar with them, I'm tempted to think that the system in Lin's Argos will have been installed according to Alde's instructions. Although Lin has mentioned that 3 pumps have leaked, she hasn't said that the heating system had otherwise played up, so hopefully it hasn't. Link to comment Share on other sites More sharing options...
747 Posted November 26, 2009 Share Posted November 26, 2009 Morning Derek, Your last posting was very well put together, concise and accurate and easily understood. Please ignore my earlier ramblings on here. I should not have joined the debate and tried everyones patience. I should explain that in the past two weeks I (and my wife) have had very little sleep due to domestic dramas with pets. The few little grey cells I have left are not at their best. As I had an hour spare this morning, I had the time to look at the Alde website and also to dig out the phone number of a friend of mine who has a 2008 Burstner with this system fitted. Guess what? ...... His had to go back to the dealership twice for a leaking pump. Luckily, his is local. He had a look at it himself when the 2nd pump leaked and was on the point of either removing the pump completely which would have meant no heating at all or fitting a valve either side of the pump to isolate it except for when it was needed. There is a Burstner owners club which may shed light on this subject. It may be a common fault and somebody may have helpful info. What I have learned is that I shall not involve myself in postings if I do not have the time to do my homework. Once again, thanks for your patience and good will Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 26, 2009 Share Posted November 26, 2009 I notice that the price of the 2755 pump is quoted on the Alde(UK) website as a whopping £159.95, which may explain why it's not that popular an option. If the pumps are fault prone, then it would be financially unpleasant should the vehicle be out of warranty when the pump began to leak. While I can appreciate that the ability to use an Alde boiler to heat a vehicle's motor might be considered well worth having in Sweden, where the Alde factory is, I'm not sure that many UK motorcaravanners would consider it a 'must have'. Link to comment Share on other sites More sharing options...
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