pedros Posted November 21, 2014 Share Posted November 21, 2014 Hello - I wonder if anyone can help with a problem I have with my Trumavent TEB fan which is located in my Trumatic heater (not sure if its a S3002 or S5002). This is my first motorhome (2003 Fiat based Ci Carioca10 euro) and the fan worked in spring this year when I bought it. However although the heater fires up correctly, the fan no longer works. I initially checked the connections at the rear, checked that it is not blocked up with fluff etc. and the fan blades were free to move. Next a neighbour checked the rear terminals and found there is no 12v supply to the fan. The answer would seem likely to be a blown fuse but I cannot locate the appropriate fuse. There is a habitation 12v fuse box with fuses for the lights, ignitions, electric step, water pump and refrigerator but none, apparently for the fan motor. I did check all those fuses anyway, just in case it was running on one of the above circuits but they were all fine. If anyone has any suggestions as to where the fuse might be located or any other ideas about the problem I would appreciate it - thanks. Link to comment Share on other sites More sharing options...
vindiboy Posted November 21, 2014 Share Posted November 21, 2014 I thought my fan had failed in my Hymer ,took it to a man who knows and it was not the fan but the thermostat switch, on the Hymer this was located above the entrance door and looked like a black raised button, i had this replaced and bobs your uncle it worked, I learned after having it replaced that sometimes a Spider or small insect can enter the " button " as it is vented and block the signal because it is similar to a fibre optic apparently,so check it is clear of debris or spider web before you proceed any further.Great Truma agent here in Romsey. Link to comment Share on other sites More sharing options...
pedros Posted November 21, 2014 Author Share Posted November 21, 2014 I'm not aware that I have a remote thermostat switch but I'll have a good look in the morning. Thanks for the suggestion. Link to comment Share on other sites More sharing options...
Brambles Posted November 22, 2014 Share Posted November 22, 2014 I think on your vehicle the fuse used is the same one as for ignitions. So if your boiler and Fridge work then power should be getting to the fan. Link to comment Share on other sites More sharing options...
vindiboy Posted November 22, 2014 Share Posted November 22, 2014 pedros - 2014-11-21 10:45 PMI'm not aware that I have a remote thermostat switch but I'll have a good look in the morning. Thanks for the suggestion.Actually it is not a switch but a sensor,I used the incorrect description in my post,sorry. Link to comment Share on other sites More sharing options...
pedros Posted November 22, 2014 Author Share Posted November 22, 2014 Thanks for your replies. I do not appear to have a room sensor and the fridge and boiler do work so I'm not sure where to look next but I'll keep researching the problem - Oh well what else would I be doing on a wet November day. Link to comment Share on other sites More sharing options...
Tracker Posted November 22, 2014 Share Posted November 22, 2014 Assuming all the fuses are OK, and if you have the electrical knowledge you could try running a temporary lead from the battery direct to the fan motor to find out if the fan works and if it does you then know the fault is between the fan and the fuse. I can't remember the details but the boiler is probably controlled by an adjustable thermostat inside the van and there may well be a separate built in stat near the fan itself that keeps the fan running to prevent overheating after the boiler is turned off and that should then turn the fan off when the boiler is cool enough. You may therefore need to delve a bit to find the point at which to connect a known 12v supply so that you can determine whether it is fan or stat at fault. Link to comment Share on other sites More sharing options...
Brambles Posted November 22, 2014 Share Posted November 22, 2014 Have you checked the switch on the front panel...this would be my next suspected item and the wires connecting to it? Link to comment Share on other sites More sharing options...
vindiboy Posted November 22, 2014 Share Posted November 22, 2014 I would suggest that if you know little about the workings of the truma,you do not mess with it, the circuit board is a very expensive bit of kit and if you knacker that !!!!!!!!and there are at least 4 sensors in the housing ,in the Hymer the brown wire was not live but neutral so all sorts of things to be aware of,your choice of course happy days. Link to comment Share on other sites More sharing options...
lennyhb Posted November 23, 2014 Share Posted November 23, 2014 I think you guys are talking about the wrong type of heater, Peter said it was either a S3002 or S5002 this is a convertor heater more commonly seen in caravans. When fitted with blow air they have a housing with a fan mounted on the back of the heat exchanger. The S3002 and S5002 have a control knob for the fan in the top of the casing on the left hand side. This is a rotary control with on/off switch and potentiometer (rheostat) for fan speed control. I would check the switch and the check the potentiometer is not open circuit, an educated guess would be the potentiometer burnt out. A new control is about £25. Edit: There aren't any expensive electronics in these heaters, just a nice simple gas heater with not much to go wrong. Link to comment Share on other sites More sharing options...
Keithl Posted November 23, 2014 Share Posted November 23, 2014 Peter, When you say there is no power to the fan did you measure actually at the fan or at the 12 volt power supply to the rear of the heater? We have basically the same heater in our MH and on the rear is a grey box containing all the connections and a small circuit board which controls the heat setting when on mains. Check the connections onto this board and make sure none have come adrift or are corroded. I suggest you do this with the mains lead unplugged as there are mains connections in this junction box. Keith. Edit. And don't just check for 12 volts between incoming wires, check to a known ground as well to ensure you haven't lost the earth connection. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 23, 2014 Share Posted November 23, 2014 And - for what it’s worth - the heater will not be a Truma S-5002 unit. The S-5002 is a whopping great ‘double-depth’ thing with twin heat-exchangers and only approved for use in caravans. Pedros’s heater is undoubtedly one of the S-3002 range. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 23, 2014 Share Posted November 23, 2014 Duplicated post... Link to comment Share on other sites More sharing options...
pedros Posted November 23, 2014 Author Share Posted November 23, 2014 Thanks again for all the interest and suggestions. This is the first post I have made on the forum and you guys are certainly friendly and helpful! Derek thanks for clarifying the actual heater model. Lenny your description of my heater set up is correct. Keith I checked the incoming 12 volt supply (there is no 240 volt) and there is no current there at all which is why I presume it is a fault in the wiring before it reaches the heater fan? There are two incoming wires (red and black) I presumed these would be wired directly back to the fuse box - but are you saying that the negative one will be going to an earth? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 24, 2014 Share Posted November 24, 2014 There are several versions of Truma’s S-3002 convector heater, with gas-ignition performed via a piezo push-button, an AA battery, or a 12V power-supply. You have confirmed that gas-ignition is still OK, but it might be useful to know which method is used to light the gas with your heater. Are the red and black cables you mention connected directly to the heater-fan unit? I’m not familiar with S-3002 heaters, but If the fan-unit is directly connected to a 12V supply, this would suggest that gas-ignition would be via piezo or AA battery and the cables are then likely to lead back to a fuse-box somewhere. I believe Keith is suggesting that you earth the black cable and recheck for 12V at the fan. I suspect that your neighbour will have done this, but one never knows... If the gas is ignited via a 12V power-supply, the cabling at the rear of the heater should be as shown in diagram C on Page 2 of this Truma document http://dealer.truma.com/_anweisungen/Truma-Katalog/pdf_verzeichnis/30_000/30040_39500.pdf If that’s the situation in your case, as gas ignition still occurs (ie. 12V power is reaching the heater but not the fan-unit) you need to explore lennyhb’s suggestions. Link to comment Share on other sites More sharing options...
pedros Posted November 25, 2014 Author Share Posted November 25, 2014 The unit has a AA battery to power the ignition so I think the issue is with the 12 v supply which goes directly to the fan. As I can't seem to find where the wiring is routed and fused perhaps I will need to get someone to look at it for me. Thanks Peter Link to comment Share on other sites More sharing options...
lennyhb Posted November 25, 2014 Share Posted November 25, 2014 Have you checked out the control switch/knob yet? You need to check your are getting power to the input side & is power getting past the control as I said earlier there is a good chance the pot has burnt out and is open circuit. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 25, 2014 Share Posted November 25, 2014 Installation instructions for a Trumavant TEB fan-unit can be found here http://dealer.truma.com/_anweisungen/Truma-Katalog/pdf_verzeichnis/40_000/40000_52400.pdf As I understand the instructions, the control-switch can be remote or integrated into the top of the heater. Pedros’s heater (with AA battery gas-ignition) will be an S-3002 model and there will be two cable connectors on the fan-unit’s rear as shown in Diagram B of the instructions. The lower connector (18 on diagram A) takes the control-switch cable’s end-plug. The upper connector (circled on Diagram B) is used to connect the fan-unit to a 12V power supply and this is where the initial check should be made to confirm whether or not 12V power is present at the fan-unit. If there’s no 12V power present at the upper connector, the control-switch and the fan-unit itself can be ignored. It should be straightforward to check for 12V power and, based on the comment in pedros’s original posting “...a neighbour checked the rear terminals and found there is no 12v supply to the fan..” this check seems to have been properly performed. Plainly, if 12V power is present at the upper connector, then the problem lies with the control-panel or the fan-unit. Link to comment Share on other sites More sharing options...
pedros Posted November 25, 2014 Author Share Posted November 25, 2014 Derek Yes that's my understanding of the issue. As there is no 12v to the unit then the problem is not on the heater fan itself but somewhere on the supply - the problem I think is how to track this back - as stated earlier all the fuses in the 12v fuse box are working. I think the previous suggestion of applying a 12 v current from a battery directly to the fan terminals would be sensible to confirm this. However in view of a previous comment that there is a risk of causing serious damage I'm not sure I want to risk doing this myself. Peter Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 26, 2014 Share Posted November 26, 2014 I’d start by confirming that there’s no 12V power at the fan’s teminals. (I know your neighbour has done this and I’ve no reason to think the check was not carried out properly, but I’d want to be absolutely certain myself that there’s no power at the fan-unit.) Clearly, if there is no power, the fan-unit won’t work and it can be safely assumed that there’s a problem of some sort in the 12V power-supply to the fan-unit. The simplest reason for there being no power is (as you said in your initial posting) that a fuse has blown. However, as you have not been able to find a blown fuse, it’s possible that the problem is due to a loose/disconnected connection or a broken wire. I believe (based on on-line comments and your initial posting) that the majority of ‘habitation’ 12V fuses is in a single fuse-box, but there may be other fuses elsewhere. Check whether there are any supplementary low-amperage 12V fuses close to your leisure-battery that look like they might relate to the fan-unit. Jury-rigging a 12V power-supply to the fan-unit should not cause harm (the caveat in an earlier posting applied to a different type of Truma heater). You might find by doing this that the fan-unit failed to operate due to a problem with the control-switch or the fan-unit itself and, if that were the case, it might explain why there’s now no 12V power reaching the fan-unit eg. it caused a fuse to blow). It might be worth trying the jury-rigging experiment as a precautionary measure to confirm that the fan-unit should operate OK once the original 12V power-supply to it was reinstated, but a 12V supply would still need restoring. The critical question is the one you asked originally - “On a 2003 CI Carioca 10 Euro, where does the 12V supply to the Truma heater’s fan-unit come from?” You might try asking this on the MotorhomeFacts website as there’s a dedicated CI-related sub-forum there http://www.motorhomefacts.com/forum-194.html or you might try the Owners Club forum http://www.rollerteamownersclub.com/ Link to comment Share on other sites More sharing options...
Brambles Posted November 26, 2014 Share Posted November 26, 2014 Derek, you have asked where the 12 volt supply comes from. Chances are it comes from the control unit mounted behind and integral to the fuse box. Probably connector JP10 pin 9 or 10. Looking at the PCB with (edit.. .the large two) relays down, the conector is middle one at top. Pin 9 and 10 are the bottom left two on the connector. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 26, 2014 Share Posted November 26, 2014 Would connector JP10 Pin 9 or 10 also provide 12V power to the boiler and fridge as you suggested earlier might be the case? Evidently Pedros’s boiler and fridge are working OK. Link to comment Share on other sites More sharing options...
Brambles Posted November 26, 2014 Share Posted November 26, 2014 Derek Uzzell - 2014-11-26 1:36 PM Would connector JP10 Pin 9 or 10 also provide 12V power to the boiler and fridge as you suggested earlier might be the case? Evidently Pedros’s boiler and fridge are working OK. According to the wiring chart, yes. I just do not know if pin 9 or 10 as it grouped them together. However on the wiring diagram it shows pin 9 connected to pin 10 directly. These are fed from fuse 1 which is the ignition fuse. (4th from the left). (PCB layout engineers really should communicate with design engineers!!!!). I am loath to suggest hauling out the fuse panel and control unit as will be a guddle of wires and some easily damaged...however because it is a mess of wires there is a high chance a wire is damaged in that area or even the connector starting to fall off the control board if wires are strained. So if doing so Pedro needs to take extreme care. The fridge uses the same circuit but is connected to a different connector .... JP9 pin2. The boiler ignition and heater fan appear to use JP10 pins 9 and 10 but no indication which way round as does not really matter. There is a possibility the installer just looped a wire from the boiler feed to the heater fan if close by so worth checking how many wires feed the boiler or if a junction box is nearby. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 26, 2014 Share Posted November 26, 2014 I think the heater may be quite close to the boiler (hard to tell from on-line photos of early-2000s Carioca 10 motorhomes) so, if all else fails, as there’s clearly 12V power at the boiler - otherwise the gas would not light - it might be better to ‘piggy back’ on the boiler’s 12V supply rather than fiddle about at the fuse-box/control-panel end. Let’s hope Peter can spot something amiss at the boiler that can be simply rectified. Link to comment Share on other sites More sharing options...
pedros Posted November 29, 2014 Author Share Posted November 29, 2014 Well I have now got a working fan again in my heater! I rigged up a 12 volt supply lead to the fan and found that it it worked when it received 12v. I then worked out that it was definitely the positive lead that was dead. So I tried to locate an in line fuse or something amiss in the wiring, but could find nothing. Then I opened up the fuse box and found it to be far more complicated than I had imagined so ensured all the connectors were tight, checked again that all the fuses were OK and it started to work again. I can only assume that it was one of the connectors inside the fuse box that was not quite seated properly. Anyway thanks again for all your ideas which were encouraging for me - I think that without your support I'd probably have had it to a dealers. Now back to sorting it out before winter. Peter :-D Link to comment Share on other sites More sharing options...
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