Derek Uzzell Posted November 23, 2010 Share Posted November 23, 2010 Connie - 2010-11-22 8:54 PM TRUMA combi 4E/6E We purchased a brand new Autocruise Startrail at the end of July 2009 and only at the end of August 2010 were our problems with the combi boiler resolved. Unfortunately, our dealer was less than helpful. Therefore in our frustration we turned to TRUMA in Derbyshire who were absolutely brilliant. Although, initially not quite believing our boiler problems - "jet engine" noise followed by whole system shutting down, with control dial showing a flashing red light - they at least did attempt to investigate. Subsequently, our motorhome was fitted ( by TRUMA in Derbyshire ) at first with a replacement boiler, followed throughout the year with two replacement printed circuit boards, unhappily our problems persisted ~ finally ~ after ongoing investigation between TRUMA in Derbyshire and TRUMA at their headquarters in Germany the fault was diagnosed as a VOLTAGE SPIKE, too much current travelling to the air circulation motor resulting in the PCB shutting down because it, incorrectly, recognises an overload. This, obviously, only happens when connected to an electric hook up. As this was our first motorhome it has certainly been frustrating and with a dealership who were only interested in selling with no after sales service we can only feel more than grateful to TRUMA in Derbyshire for their outstanding help. Retrospectively we should have rejected this van at the outset, but of course there is a time limit to this and, as 'first timers', we initially thought the problem was with us ! Amanda - I hope this has been helpful, my advice would be contact TRUMA in Derbyshire as it appears you also need a PCB made in Germany specifically for this VOLTAGE SPIKE problem. Truma's explanation is intriguing. While it's certainly the case that mains voltage can fluctuate and, in extreme cases surge sufficiently to damage electrical equipment, manufacturers of electrical applliances will normally allow plenty of scope for voltage highs and lows. There's no reason to expect UK 230V power-supplies to be any more 'spiky' than, say, those in France or Germany, so, if the original Combi-E design had proved to be sensitive to mains-power voltage variations, one might have expected this fact to have been identified early on and measures taken to combat it long ago. Even if the 230V power-source were spiky, this shouldn't directly affect the 12V air-circulation motor. It's more likely that it's the PCB's 'logic' that's the culprit, reacting to a voltage spike on the EHU by revving up the fan-motor and shutting down the heater. If Truma now has a modified PCB to better handle EHU voltage variations, then owners of Combi-4E and 6E appliances should really be making waves to have this retro-fitted to their heaters. Let's not forget the smelly C-Series saga that went on for years before accidents with overheating applliances compelled Truma to issue a safety recall affecting thousands of heaters. Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 23, 2010 Share Posted November 23, 2010 All true, and the symptoms sound pretty much identical. So at least that offers the prospect of progress. I guess the supply on a campsite is rather more prone to odd spikes etc as others connect their vehicles, but agree that the Truma explanation sounds like a bit of flannel dressed up as an excuse! I would suspect either a duff batch of boards they don't, for whatever reason, want to admit to, or as Derek suggests the logic is wrong. However, it seems odd that this has not emerged as a widespread problem, so would be more inclined to a defective, or wrong, component somewhere on certain boards as a cause. Lets hope it gets fixed quickly. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 1, 2011 Share Posted March 1, 2011 A follow-up on this... My understanding now is that the voltage 'spiking' mentioned above is not caused by fluctuations in the 230V supply being provided to the motorhome while on a campsite electric hook-up (EHU), but results from the way that the motorhome's on-board battery-charger may operate. It's been ascertained that (quite a few) Truma "Combi" heaters have proved unduly sensitive to the charging regimen employed by certain modern switch-mode chargers that have been fitted to leisure vehicles during the last several years. The problem will only reveal itself when the charger is operating, which will only be when the motorhome is on EHU. The voltage spiking does not damage the heater, but it can confuse the "Combi's" 'logic' embedded in the heater's printed circuitry. The problem can be resolved temporarily by carrying out the shut-down/restart procedure (or, presumably, by switching off the charger). However, this will not provide a permanent cure. I've been told that a couple of (software/firmware/hardware?) revisions to the "Combi" printed-circuit board (PCB) have been made and the latest PCBs should now be fully comfortable with all modern battery-chargers. The good news is that Truma will (apparently) replace free-of-charge the PCB of any "Combi" displaying the type of odd behaviour mentioned by Amanda and Connie, even if the heater is outside Truma's 24-month period of warranty. It needs to be emphasised that there won't be a general recall over this and, if your "Combi" heater is behaving normally while your motorhome is on EHU, there's absolutely no reason to replace the PCB. Link to comment Share on other sites More sharing options...
Connie Posted March 1, 2011 Share Posted March 1, 2011 Excellent - at last a concise explanation regarding the problems encountered with the Truma "combi" boiler. Quite a few owners with this form of heating may not realise they have a problem if their van is not used during cold weather. The ridiculous stress encountered as first time motorhomers was enough to try the patience of a saint, only alleviated when Truma in Derbyshire and eventually Germany accepted we had a problem. Many thanks Derek. Link to comment Share on other sites More sharing options...
Amanda Posted March 1, 2011 Author Share Posted March 1, 2011 :-D Thanks so much for this. The dealer didn't believe us and said it was 'normal' behaviour and we just couldn't understand it. At least now we have something concrete to tell them and can get it fixed. We just couldn't produce the effect on demand. We have had a couple of weekends out now and each time it has performed the jet engine and we have done the shut down and restart. Still love the van and still planning on Easter in Scotland. Thanks again. Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted March 1, 2011 Share Posted March 1, 2011 My 6002 EH which I have posted on recently regards lack of electric operation has finally had a diagnosis :-S (I was at Belgian dealer last week having yearly damp check, and looking at other vans at various dealers) It seems the PCP board AND the element have burnt out, luckily the belgian dealer had no parts in stock! as they quoated (wait for it) 546 euro and 140 Euro for each! + labour :-S a very nice man (mobile truma UK service agent) has quoted between £100-150 for PCP and £30-40 for element, plus £40-50 labour.....A bit of a difference! next time I will just get a gas heater these are to complex *-) Link to comment Share on other sites More sharing options...
Mel B Posted March 1, 2011 Share Posted March 1, 2011 My goodness Judge ... are you trying to tell me that something is actually CHEAPER in the UK!!!!!!! Well, by heck, I'll go to the end of our street .....! :-D Link to comment Share on other sites More sharing options...
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