Jump to content

Truma heater problem


Recommended Posts

I hope someone can give me an answer to a slight problem, our water heater has been working fine until today. Switched heater off and gas off for a short journey, when I parked up and tried to put heater on again the red light on control panel blinked but then went off and heater isn't working, anyone got any ideas on how to fix this?



Link to comment
Share on other sites

keep trying it, sometimes its just an air lock then there will be a backfire and it will light, obvious questions, have you got gas, is it turned on, is the boiler outside cover on? can you get at the gas jet to try blowing it with a can of compressed air?



Link to comment
Share on other sites



I believe you own a 2003 McLouis 361 motorhome that you obtained in September/October of last year.



The following Ultrastore boiler trouble-shooting procedure may be helpful:




Is there gas available?


Are the gas isolation taps switched on?


Is the boiler’s external cowl cover removed?


Is 12V power available and working?




If YES to all above:


When the boiler is switched on does the control-panel light NEVER illuminate?


If YES, check the fuse on the boiler’s printed-circuit board and replace if necessary.


When the boiler is switched on does the red light come on straight away?


if YES, the boiler’s printed-circuit board will probably need replacement.


When the boiler is switched on does the red light come on after about 6 seconds?


If YES, when the boiler is switched on can its gas-valve be heard to "clunk" as it opens?


If NO, the gas-valve probaly needs replacing.


Can the boiler’s gas spark-ignitor be heard clicking after the gas-valve has opened?


If NO, there are several potential reasons and it will be necessary to seek technical assistance.





Logically, if the boiler does not fire up properly during the ignition phase, the red failure-light should illuminate and stay lit, but you have said that the light just blinked red and went off, and the boiler was then apparently ‘dead'.


This sounds like a basic electrical fault, with either no 12V power reaching the boiler or the fuse on the boiler’s printed-circuit board having failed.


This 2009 discussion may be worth reading:




Link to comment
Share on other sites

Are you on mains hook up or relying solely on 12 volt batteries? And if so what is your State of Charge?


Derek mentioned no 12 volts as a possible cause but low voltage may also be likely and this may be worth investigating.



Link to comment
Share on other sites

itz - 2016-04-01 8:28 AM


Last night went wash before bed and heater had started working again, got up this morning and no hot water again...


Presumably you are saying that (last night) your boiler went through its normal start-up sequence - switch boiler on, control-panel light goes green and water gets heated - and next time (this morning) you are back to the problem you asked about initially - switch boiler on, red light blinks and goes off (or light does something else) and water does not get heated.


If the boiler is original it is getting long in the tooth, so the problem may be age-related. As the fault seems to be sporadic the PCB falls under suspicion. Dunno - unless the fault cures itself, you’ll need someone familiar with Truma Ultrastore boilers to carry out some diagnostic checks.


Link to comment
Share on other sites

I assume the OP is using propane.


I had problems with my Gaslow bottle during coolish night time temperatures, especially early morning. The boiler wouldn't fire up because pressure was low and probably had a high butane content through filling mostly in mainland Europe. This was with a half full bottle or less. I now empty the bottle and refill with 100% propane in UK before a trip.


All the other gas appliances worked fine. Let's hope it's just a gas problem.

Link to comment
Share on other sites

Even if no (or an inadequate supply of) gas were being delivered to the boiler (eg. the gas-bottle is completely empty, the bottle or a gas-isolation-valve has been turned off, the gas-pressure is too low, the boiler’s own gas-valve fails to open) when the boiler is switched on the red light on its control-panel should still illuminate continuously to indicate there’s a fault.


From Rick’s description, when the problem occurs the red fault-light illuminates briefly (so there’s 12V power apparently reaching the control-panel) but that’s it...

Link to comment
Share on other sites

Thanks for replies and suggestions, you are right Derek I got the MH late last year, this is the first trip undertaken so far so one long learning curve. We are currently in Saint Hilaire de Ruiz and on a camp site with an electric hook up.

We left the UK early on Monday morning braving the storm by going under the channel, we made one stop on the way here, managed to wreck the turbo charger and the machine is currently in garage having a new one fitted. The camp site we are on is all mobile homes, I use the term loosely as they are just caravans on blocks and are by no means mobile.

All the OH's family are gathering here for a wedding that takes place in the morning, followed apparently by two days of eating and drinking. The camp site is not officially open until mid April so no shower blocks available at the moment, strip washes are fine, but really hope I can have a warm shower in MH tonight ready for the morning, if not it's a cold shower for me with the heating turned up high along with a fan heater to thaw me out afterwards.

Link to comment
Share on other sites

My thoughts on this problem as we have suffered a similar issue. The boiler when switched on clicks as the gas valve opens (although the igniter can be heard the gas may or may-not light) and then the red fault light comes on. The issue with our boiler was condensation on the printed circuit board which causes the igniter transformer to spark via the surface condensation rather than through the electrodes and spark gap so the gas sometime fails to light under these circumstances. To solve this problem remove the PCB from under the triangular shaped cover by unplugging the connectors at the top. Then withdraw the PCB by pulling upwards, the igniter connections are at the bottom, You may look at the PCB and think no condensation is apparent however it may well be between the components and the printed circuit board itself, So you need to dry the board thoroughly for several hours in front of a heater or by using a hairdryer, and then leave it out of the boiler for several hours also dry the enclosure thoroughly. If you try to rush and do it too quickly you will need to do it again so its better to leave it a good length of time. I also applied some hot melt glue to the igniter output terminals to provide insulation and the issue has never occurred again. [make sure you get the PCB plugged correctly into the socket at the bottom when re-assembling] and the plugs in the correct positions on the top edge take a photo first to be sure. Of course power and gas should be switched off before doing any work.

Hope this helps


Link to comment
Share on other sites

Condensation is mentioned in this Truma Ultrastore-related discussion




Rick’s inquiry here




includes a photo of a Truma boiler’s external ‘cowl cover’. I had begun to wonder about Rick’s photo of the boiler’s control-panel in this thread - as the panel did not seem to match the panel I’d expect - but then I found this 2012 forum thread that shows exactly the same panel:




(It’s water under the bridge, but I now see that BGD’s wish to add a green ‘boiler is ON’ light to his control-panel was implemented (fairly straightforwardly) by a French DIYer.)




In my posting of 1 April 2016 8:57 AM above I assumed that the LED on Rick’s boiler should illuminate green when the boiler is operating normally - this is clearly not the case.


What happens with this basic control-panel is that its red LED should illuminate ONLY if there is a fault. When the boiler is operating normally the LED does not illuminate and there is nothing to visually confirm that the boiler is running or when the chosen water-temperature is attained


This puts a different complexion on Rick’s problem as the red LED blinking momentarily and then going out might not be too unusual. This would not explain why Rick’s boiler evidently fails to heat water reliably, but whatever the cause of that (eg. a wonky thermostat) the reason might not be ‘recognised’ by the boiler’s electronics as sufficient to result in the red LED coming on continuously.


Rick’s control-panel has a 3-position switch, with the central position being OFF. Before resorting to Dave’s PCB-warming suggestion I’d experiment by selecting each of the water-heating temperatures and check whether the boiler attempts to fire up.


As has been said above, when the boiler is switched on it should be possible to hear the boiler’s gas-valve open and its igniter ‘firing’ (and if either of those actions fail to happen the red LED should illuminate continuously). But when the boiler is actually heating water it should be obvious this is taking place as the boiler will be exhausting through the external cowl.


(It’s perhaps worth adding that Truma gas-only boilers do not ‘maintain’ the water temperature selected at the control-panel. Once the chosen temperature has been reached the boiler will shut down and water-heating will not restart until the water temperature has fallen appreciably. Running a boiler in the evening until the water is piping hot and then leaving the heater switched on all night will not guarantee that there will be piping hot water in the morning. Maybe there will, but if in the morning the temperature of the water in the boiler has dropped to just before heating restarts, all you’ll have is tepid water.)

Link to comment
Share on other sites

Another thread regarding this problem.


You should understand that the several thousand volts that the ignition transformer produces can and possibly will also effect the general operation of the electronics when presented via the condensation to other sections of the PCB. The condensation acting as a conductor.

This particular problem causes the boiler to be possibly intermittent in operation as sometimes the condensation can dry out slightly and the boiler will ignite only for the condensation to form again preventing the boiler from working. Allowing plenty of time for the PCB to thoroughly dry cannot be over emphasised for a successful outcome.

As for Derek's suggestion that this boiler will not maintain the water temperature. This is not my experience as when the boiler is turned on it will reach temperature then will cycle every 30 minutes or so to maintain temperature and when drawing water the boiler will almost immediately ignite to warm it up again. Although it takes a long while to actually warm the water to the required temperature so one could be forgiven to think it the thermostat had a high level of hysteresis when it actually does not.


Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...