flightcom Posted January 2, 2015 Share Posted January 2, 2015 Having read through loads of forums I haven't managed to find any with my problem, so I've taken the plunge and joined here. I have an Elnagh Joxy 2003 with the Truma c6002 gas only heater. It's been fine with both hot water and heating. The problem now is that the heater blower is on full blast permanently, this causes red light very quickly. If I disconnect the fan and select water only it works but fails if I select heat or connect up the fan. The voltage to the fan is 13.5 which I suspect is the problem. I've done numerous checks on heat sensors etc and whilst they have variable resistance with temperature I don't know if they are correct. Does anyone have any info on voltage to the fan and resistance of sensors etc. or how the speed of the fan varies. Any help appreciated. Link to comment Share on other sites More sharing options...
Keithl Posted January 2, 2015 Share Posted January 2, 2015 Hi Michael and welcome to the forum, If you haven't got them already you can download operating and installation instructions from Truma's site here... Link. Other than that I'm afraid I can't help as we've got a Trumatic convector. Keith. Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 2, 2015 Share Posted January 2, 2015 Hello Flightcom, I could write a book on this heater, inheriting as I did a faulty one with my current van. I will tell you the advice first given to me, which was that the main PCB was likely to be the culprit, this is a complex bit of electronics, having contacted Truma themselves they told me to send the board in for testing, other advice was to disconnect the various multiplugs that go to this board, then reconnect them again after spraying with electronic contact spray ( NOT anything else ) which I did several times. With no joy I then sent the board to Truma, who eventually returned it saying no fault found........................I then replaced the main blower motor, the combustion blower motor ( yes there are two blower motors ) , and stripped down the unit, cleaning and replacing gaskets and components as I went. Put it all back together same fault,............Mmmmmm, then spotted the very same main PCB board for sale, thought well what have I got to lose, and bought it. Yes it was the board after all, and this was confirmed by putting the old board back when immediately it returned to a faulty state which was characterised by either a slow fan, no fan, or very fast fan. I subsequently telephoned Truma for their comments, which were less than helpful, stating I should have shipped the whole heater to them for testing, even though they said just the board would be fine. If I can help any further I'd be happy to, but based on my experience and that of others the main PCB is normally the item to be suspect or the connections to it , but it's around £400, which is a couple of bob if that's not the problem. ;-) P.S I have a blower motor and combustion motor in my probably never to be used spares box. :D Link to comment Share on other sites More sharing options...
flightcom Posted January 2, 2015 Author Share Posted January 2, 2015 Thanks for the reply. It may well be the case that I'll need a new board but I would rather make some more tests before splashing out that sort of cash. My trade was electronics albeit many years ago now. A circuit diagram would be ideal but can't find one and it's much too complicated to reverse engineer. The room sensor measures 25k ohms cold and less than 15 when warm. This seems to be in parallel with the control temp sensor which is 4.5k to 6k. If these sensors are responsible for the fan speed then it doesn't seem right with such a small parallel resistance change. Of course I don't have any idea wether these figures are correct, they may be faulty. I do know that I can remove both pcb sockets on the top of the board and the one on bottom left and the fan still runs at full belt. The bottom right socket contains the 12v power to the board. What I need is a spare board. I wonder if your old pcb would help me if you still have it. Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 3, 2015 Share Posted January 3, 2015 You say the heater has been working satisfactorily up until this point, in which case you’d be aware the start up sequence. The air circulation fan should only turn very slowly to begin with, the combustion fan will start to turn, ( not that you can see or hear it ), you should then hear various clicks as the gas solenoid opens up, and the igniter fires up so igniting the gas, then the fan speed should only gradually increase speed but coinciding with the build up of heat from the burner which can take some time, given of course that the heating control has been turned up to demand heat, if your fan is running at full tilt to begin with in my experience it certainly shouldn’t . As for the “button” room sensor you can rule that out as part of the problem by merely taking it out and connecting the two wires that go to it, any problem with them seems to be just going open circuit, I believe there is another temp sensor behind and incorporated into the rotary control switch which I believe you are aware of. You may also be aware of and know far more than me about IC chips, but there are loads of them on the PCB, and what I assume are miniature relays.......do these fail ? I also examined my board under a high mag looking for dry joints, there were none that I could see But as I say your fan should not be going at full tilt to begin with so let’s not muddy the waters for now ( as I have done ) with room temp sensors, but one thing, does the heater work on hot water only setting, I am not entirely clear on that point. A bit of insomnia tonight hence being on the net at 4 am, will log on later today and see how you’re getting on, I am also happy to give you my home phone number via a PM if that would help. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 3, 2015 Share Posted January 3, 2015 flightcom I’m not 100% clear what your "The voltage to the fan is 13.5 which I suspect is the problem” statement means. Are you saying that the power-supply to the Truma heater is, say, 12.7V and this is ‘stepped up’ somehow so that the fan receives 13.5V, or what? As the heater is designed to operate when the motorhome’s onboard battery-charger is running, or when the vehicle is being driven and the leisure-battery is being alternator-charged, the voltage of the heater’s power-supply is going to vary from mid-12s to mid-14s. The strong likelihood is that the problem lies with the pcb and, realistically, the only way to confirm this would be to fit a replacement pcb that’s known to be in full working order and see if the fault disappears. If you have not already done so, it might be worth you contacting Truma(UK) for advice http://www.truma.com/uk/en/home/service-center.php Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 3, 2015 Share Posted January 3, 2015 I assumed the OP was probably testing whilst using EHU, hence the voltage reading. As far as I'm aware Truma themselves will now not deal directly with members of the public, referring enquiries to service agents. In the meantime the OP I guess is trying to minimise costs by seeking advice from anyone else having had a similar problem, which I have, perhaps there's some value in that, and the advice that the PCB is likely to be the problem I have already flagged up. :-S Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 3, 2015 Share Posted January 3, 2015 I never assume anything. I’m not certain what Truma(UK)’s stance is nowadays. I was under the impression (gained from discussion with their technicians at the lastt NEC Show) that they are prepared to offer advice but would no longer agree to members of the public making appontments directly with them to bring their vehicles in for diagnosis/repair. If that were required, it would need to be arranged though a Truma agent. If flightcom contacts Truma(UK) I’m sure they’ll offer him some sort of advice. Link to comment Share on other sites More sharing options...
lennyhb Posted January 3, 2015 Share Posted January 3, 2015 Derek Uzzell - 2015-01-03 10:17 AM I’m not certain what Truma(UK)’s stance is nowadays. Not good I phoned them a few weeks ago, they just tell you to contact one of their service agents. Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 3, 2015 Share Posted January 3, 2015 Derek Uzzell - 2015-01-03 10:17 AM I never assume anything. . With respect, I think you often assume you know more than anyone else. ;-) As for contacting Truma for advice, in my case it was about as much use as an ashtray on a motorbike, although an agent may be his final option, but I'm trying to help the bloke out here based on my personal experience, both of Truma, and my own troubleshooting which in the end turned out to be better than Trumas. with apologies to the OP, who may now have to scroll back up the top of the page. Link to comment Share on other sites More sharing options...
flightcom Posted January 3, 2015 Author Share Posted January 3, 2015 Thanks for replies. Yes I am aware of the start up sequence and it all works as it should when the summer hot water settings are selected. I can just about hear the combustion fan then the click of the solenoid and the gas ignition. 20 to 30 minutes later I have hot water and the amber light goes out till it needs topping up. My reasoning with the temp sensors was that they must have something to do with the fan speed, which of course they do but it's not that simple, other sensors on or off the pcb also have a say in the matter. The 13.5 volts that is permenantly on the fan is from the battery (with hook up). This I believe should be 0 volts until heating is selected when as you say the fan will start turning slowly with low volts and build up speed with higher volts as the boiler warms. When the temp selected is reached the the boiler settles down in an on off sequence at lower fan speeds to maintain this temp. My unit locks out very quickly because the fan is on full blast at the start, this is likely the pcb which also has an input to fan speed and the many ic,s on it are very sensitive. These ic,s are unfortunately soldered in, if they were plug in it would provide another avenue of investigation instead of board changing. Whilst I accept that I may eventually have to purchase a new pcb, I have read many posts where people have done so only to find it was something else. Maybe it's possible therefore to replace the pcb with a pcb of a different fault to improve confidence, won't work every time, depends on fault, but worth a try. Maybe we could have a forum of spares!. Have been trying the Truma help line for two weeks with no success, get all sorts of no reply or waiting or closed messages, probably Xmas break, will try on Monday. My PCB has several numbers on it: C60E/1, 30115381 + a very long number. I have removed it and investigated with an eye glass but nothing stands out. By the way be carefully when removing and fitting pcb,s as the components are very static sensitive. I'll soon start looking at where I can get a replacement, any advice appreciated. Link to comment Share on other sites More sharing options...
StuartO Posted January 3, 2015 Share Posted January 3, 2015 There appears to be a pcb on EBay at the moment, would that be any use? http://www.ebay.co.uk/itm/TRUMA-C6002-EH-CIRCUIT-BOARD-PCB-34010-07200-BOILER-GENUINE-REPLACEMENT-PART-/331128134043?pt=UK_Campervan_Caravan_Accessories&hash=item4d18c6599b Except the photo doesn;t look anything like Joe's photo of a C6002 pcb??? Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 3, 2015 Share Posted January 3, 2015 Flightcom You sound like a savvy man, and I'd say you're bang on the money that the room sensors are not the only thing in play as I would think the PCB is connected to sensors within the boiler assembly so that when the temp is reached the burner jets may be throttled back as well as the fan speed. Complicated stuff, I've sadly thrown my old board out, but I believe they are quite specific to boiler serial numbers in any event. Leisure spares direct sell the boards, but perhaps at the end of the day a kindly Truma approved engineer may be the way to go just to see if they'd be prepared to stick a board in to try, good luck. Edit...above post, no that's the PCB for the C6002EH boiler which is additional to the main PCB. Link to comment Share on other sites More sharing options...
flightcom Posted January 3, 2015 Author Share Posted January 3, 2015 Thanks for that but doesn't look like mine. Suspect many different boards and would have to careful to get correct one even if it looks the same. Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 3, 2015 Share Posted January 3, 2015 flightcom - 2015-01-03 12:51 PM Thanks for that but doesn't look like mine. Suspect many different boards and would have to careful to get correct one even if it looks the same. Take a look http://www.leisureshopdirect.com/caravan/home/product_41290/truma_combi_pcb_for_c6002_c_version.aspx Link to comment Share on other sites More sharing options...
flightcom Posted January 3, 2015 Author Share Posted January 3, 2015 Thanks again. I'll try the Truma route next week. Will post any results. ATB Link to comment Share on other sites More sharing options...
kevina Posted January 3, 2015 Share Posted January 3, 2015 I had a very similar problem when we bought our one year old Rapido, it cost nothing to fix and may give you a clue as to your problem. Symptoms were similar, after turning on the heat the burner output and fans would rapidly rise to maximum regardless of the temperature setting. The Rapido fitter had taken both ends of the sensor wires to the same terminal on the control box, and both ends of the (presumably) overheat sensors to the other terminal. Once figured out a quick cut and recrimp and all was fine. It may be that you have a short or broken wire on the wires between the sensor and the terminals, worth a quick resistance/continuity test. The sensor is approx an 8Kohm varistor. Kev Link to comment Share on other sites More sharing options...
flightcom Posted January 19, 2015 Author Share Posted January 19, 2015 Hi, just read your reply again to my original query. I have taken out my heating blower motor, taken it apart and found a diode blown apart. I've now fitted a new diode obtained on line and refitted the motor. I'm pretty sure that that will fix the motor but I notice that you have a spare, don't know if it's the same but just in case where from and how much did it cost. I now have the pcb on my desk and checking some obvious components but to be honest without a cct diagram and parts list I would have to be very lucky to find a fault. Have today identified a part number and cost of a replacement via leisuresparesdirect so am slowly coming round to having to spend the £257. There's also always that little doubt that I haven't found what blew the board in the first place. Watch this space! Link to comment Share on other sites More sharing options...
StuartO Posted January 19, 2015 Share Posted January 19, 2015 Before you get carried away and buy a new PCB, would it be worth investigating the cost of replacing the whole heater with a gas/electric unit? A new one would perhaps be far too expensive as a reatil purchase but a used one from a caravan breaker? Ours has both elecetric and gas heating and when we're on an EHU I'm sure the electric heating option adds real value. Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 19, 2015 Share Posted January 19, 2015 flightcom - 2015-01-19 12:51 PM Hi, just read your reply again to my original query. I have taken out my heating blower motor, taken it apart and found a diode blown apart. I've now fitted a new diode obtained on line and refitted the motor. I'm pretty sure that that will fix the motor but I notice that you have a spare, don't know if it's the same but just in case where from and how much did it cost. I now have the pcb on my desk and checking some obvious components but to be honest without a cct diagram and parts list I would have to be very lucky to find a fault. Have today identified a part number and cost of a replacement via leisuresparesdirect so am slowly coming round to having to spend the £257. There's also always that little doubt that I haven't found what blew the board in the first place. Watch this space! I guess your replying to my earlier post, yes I do have a brand new blower motor, it was never fitted, only connected to the blower motors wiring harness from the PCB briefly that eliminated the existing one being at fault, I would have replaced it anyway and fitted it in the housing but was completely defeated when attempting to undo the small alan grub screw that secures the fan assembly on to it's shaft, so stuck with the "old" one. I have no use for it, if you are interested in purchase please send me a PM, in the meantime I'll look up how much I paid for it, and if we can arrive at a mutually agreeable price. I note the other poster suggesting obtaining a whole unit from a breaker, in my experience they know exactly what these things are worth, but given that you could buy a whole lot of trouble, unless of course some kind of guarantee was offered it's not the route I'd take. There is currently a brand new one available from Magnum Motorhomes, I think it's £975. P.S, now been 12 months since I repaired my heater, and on replacing the PCB that would appear to be the only fault............as far as I can tell nothing "blew it" it just developed a fault. Link to comment Share on other sites More sharing options...
flightcom Posted January 28, 2015 Author Share Posted January 28, 2015 Sorry it's taking me so long to get back, only on this job once a week. Have now sourced a pcb from e bay which should arrive trow. Although I have repaired the blower motor I think I might take the cautious route and replace. If you still have yours how much would it cost? I can be reached on 01352 810275. Link to comment Share on other sites More sharing options...
Thewad Posted January 28, 2015 Share Posted January 28, 2015 Sorry to hijack your thread but i have same heater, different problem (i think) when heat is selected on gas only all works ok within 5 mins and sounds like a small hovercraft. However if i select mains only, heater still seems to heat up but i only get a 'trickle' of heat coming out which i would describe as useless to pathetic i cant believe this is correct any advice please Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 28, 2015 Share Posted January 28, 2015 That sounds about right... A Truma C-6002EH heater has a maximum heat output of 6kW on gas only and the blower-fan’s speed is matched to the heat ouput. Consequently, when the heater’s ouput is high, so is the fan’s speed. (6kw ouput = fan sounding like a jet engine.) When the heater is on mains-electricity only, its two heating elements produce an output of either 900W or 1800W and the blower fan’s speed is matched to that output. The fan speed will remain quite low and the volume and temperature of the air emerging from the blown-air outlets will alo be relatively low. Optimising the installation to comply with Truma’s guidelines (something regularly ignored by motorhome manufacturers) may help, but air-heating via mains-electricity should be considered as ‘background heating’. Link to comment Share on other sites More sharing options...
Guest Joe90 Posted January 28, 2015 Share Posted January 28, 2015 To TheWad Worth adding that you can select BOTH gas and electric heating, although the control switches and symbols are hardly intuitive, and if on mains hook up provides a very fast warm up of the vehicles interior, you'll be stripping off in no time.........as the previous poster has noted the fan speed after about 4/5 minutes really takes off, but should settle back as soon as the set room temperature is reached, the fan speed coinciding as it does with the gradual warm up of the unit. As Derek states, best to consider the electric only option as background heat only, though warm the van up thoroughly on the gas and electric option first and you may well find the electric only option on the highest setting keeps you quite toasty, although on the rare occasions we're on hookup if needed we supplement it with a fan heater .......... so your heater sounds fine. ;-) Link to comment Share on other sites More sharing options...
Thewad Posted January 28, 2015 Share Posted January 28, 2015 Thank you for the informative replies it would appear that all is 'normal' not that I use it much. I had tried it a few times last year and just thought I was doing something wrong :$ Link to comment Share on other sites More sharing options...
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