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Old 05-29-2024, 08:42 AM   #1
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Truma Combi - House lights pulsing when running

I did a quick search here but didn't find an answer, and we are scheduled for warranty service in early July on our new 2024 Isata3 Freedom Edition.


One of the issues is that when the Truma Combi burner (and diesel pump) are running the house LED lights all pulse significantly.


Has anyone else with the Truma Combi experienced this, and if so did you find the culprit? I know early on when I mentioned it on the Facebook group that someone else with the Freedom Edition said they had the same issue.


We had the safety recall to replace the 12V master cutoff done but that didn't resolve the issue. The tech at that time check grounds and other +12V connections but said he didn't see anything loose.


I had to pull the bottom drawer under the counter top to get to the Truma serial number info for the warranty and spotted a 12V ground bus bar. I checked that all the screws were properly torqued so no joy there.


I thought that if anyone else had this issue and fixed it that I might be able to knock it off the list for Dynamax to fix.
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Old 05-29-2024, 10:09 AM   #2
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Are you sure its just the combi and not the water pump? When I see this, it is mostly with the water pump and the lights flicker. LED lights seem to be voltage sensitive and a pulsing pump seems to fluctuate the voltage.

I don't recall what was done to correct it. Checking on that.
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Old 05-29-2024, 10:38 AM   #3
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It appears to just be the ignitor plug when it first fires up.

Truma suggested an isolated 30 amp DC to DC power supply. The problem is, any light that originates from Firefly, would have to return to a ground on the isolated side of the power supply. That is an issue for reading battery in/out as that is on the non-isolated side of the power supply. The shunt would not be accurate.
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Old 05-29-2024, 10:51 AM   #4
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Thanks,


No it is NOT the water pump. There is a momentary flicker when the water pump starts up, but I expect that.


Brian, it happens at startup and wasn't certain if it was the diesel pump or the burner (igniter).



I also had it happen after I had turned off the Combi (hit off on FireFly). When it was turning off the lights pulsed again but for a much shorter time interval. It might have just been a bit of a race condition where it was just ready do kick off the burner again at the same time I told it to shut down.


So it sounds like there isn't any good solution for this issue, at least at this time.
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Old 05-29-2024, 10:54 AM   #5
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It appears to be the glow plug on the ignitor. We're going to look at the light voltage range. Maybe it is narrower than that it needs to be.
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Old 05-29-2024, 10:57 AM   #6
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Thanks Brian,


I'll talk with Greg when we review the items to be corrected in July. I'm hoping that it can be resolved, or minimized. It is a pretty strong strobe effect when it happens.
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Old 05-30-2024, 08:56 AM   #7
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Originally Posted by burtbick View Post
I did a quick search here but didn't find an answer, and we are scheduled for warranty service in early July on our new 2024 Isata3 Freedom Edition.


One of the issues is that when the Truma Combi burner (and diesel pump) are running the house LED lights all pulse significantly.


Has anyone else with the Truma Combi experienced this, and if so did you find the culprit? I know early on when I mentioned it on the Facebook group that someone else with the Freedom Edition said they had the same issue.


We had the safety recall to replace the 12V master cutoff done but that didn't resolve the issue. The tech at that time check grounds and other +12V connections but said he didn't see anything loose.


I had to pull the bottom drawer under the counter top to get to the Truma serial number info for the warranty and spotted a 12V ground bus bar. I checked that all the screws were properly torqued so no joy there.


I thought that if anyone else had this issue and fixed it that I might be able to knock it off the list for Dynamax to fix.
We have the same issue with the Truma ignition. However, Im noticing now that sometimes Im getting pulsing lights when nothing is running other than the solar charging. I cant seem to isolate it to anything. The only thing that was on was the lights.
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Old 05-30-2024, 09:29 AM   #8
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So far I have only seen the pulsing lights when the Combi is running. That is the burner is operating. Or as Brian says the glow plug is heating. So not 100% sure other than when the blower is running and the burner is not starting up the lights are fine.


I did notice one time that when I turned off the Combi from FireFly that there was a shorter period of the lights strobing. But that might have just been some kind of race condition where I turned it off in FireFly and it was just starting the burner up again.


Brian alluded to the possibility of adjusting a setting for the LED lighting that might help with the issue, but I won't know more on that until we get to Dyanmax in early July.


In the meantime we are going to try a trip to Florida around the middle of June so we will see what shakes out on an actual camping trip.
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Old 05-30-2024, 09:34 AM   #9
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One other thing that I've seen with the lights that I need to track down.


The other day I had an issue where I couldn't get the lights to turn on from the FireFly panel OR the hardwired panel by the steps.


That did clear after a few minutes.


No issues after that until yesterday when I had it happen again. But I may have spotted what the issue is that triggers it. I was tapping the FireFly panel to wake it up and happened to do it near the OFF button on the home screen. So in effect I may have hit the master lights OFF while they were already off.


So once again taping the ON button on that screen didn't get the lights on and the panel by the steps also wasn't doing anything. But for grins I selected another screen. In this case the power screen. Then back to Home and the ON button was working again.


It's almost like I had hit the "clean" button to lock the screen for cleaning but I definitely did not. And in any case I could change pages and then things were working again.


I'll see if I can duplicate it one more time when I get a chance.
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Old 05-30-2024, 09:49 AM   #10
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So far I have only seen the pulsing lights when the Combi is running. That is the burner is operating. Or as Brian says the glow plug is heating. So not 100% sure other than when the blower is running and the burner is not starting up the lights are fine.


I did notice one time that when I turned off the Combi from FireFly that there was a shorter period of the lights strobing. But that might have just been some kind of race condition where I turned it off in FireFly and it was just starting the burner up again.


Brian alluded to the possibility of adjusting a setting for the LED lighting that might help with the issue, but I won't know more on that until we get to Dyanmax in early July.


In the meantime we are going to try a trip to Florida around the middle of June so we will see what shakes out on an actual camping trip.
We start our full time adventure next Tuesday so I'll be able to spend more time tracking some of these things down as well. After our trip to AK I want to swing by Dynamax for a full run through on any issues. That will be in September so by then you'll have figured it all out for us during your trip to Dynamax in July!
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Old 05-30-2024, 10:03 AM   #11
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I'm hoping that we will have things resolved at Dynamax.


While we had 20 items so far most of them have been minor. And frankly that is really on the dealer not doing a real "PDI" There were so many things missed. And due to our situation at the time I wasn't able to do a detailed PDI myself or I would have caught most of the issues before tanking delivery.


Fortunately I can handle most of the repairs myself so I've pared the list down to 10 items for Dynamax at this point. Two of the biggest ones relate to the slide, and the 3rd is the strobing of the LED lighting. And we have a galley window that is fogged, which was pointed out at the time we picked up the MH.



The rest are pretty minor but I figured I would let them take care of it while the slide is getting addressed.


I can band aid my biggest concern with the slide when would be water intrusion at the bottom with the slide retracted and driving in rain. The bottom of the slide is out about 1/2" compared to the top so the slide is not even touching the D seal at the bottom front. Like this is being off 1 or 2 gears on the gear rack. Most likely the bottom gear rack.



I can band aid that with some weather striping to form a seal. It probably wouldn't manage to get water past the bottom wipe seal but I don't want to take the chance. The other issue that I spotted with the slide is with the rollers on the outside that are supposed to support the slide. Many of the rollers are NOT contacting the bottom of the slide room so most of the weight is on the front most and rear rollers.



Good luck on your adventure and safe travels. If you encounter any interesting things with the RV be sure to pass them on, and I'll do the same. And if I get some positive results with the Combi strobe light issue I'll pass that along.
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Old 05-30-2024, 10:18 AM   #12
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Fortunately we were able to spend an entire day doing our PDI and the dealer was excellent so we got virtually everything resolved. I have only a couple of issues, like the slide being out a bit, that need to be looked at. Anything else that has cropped up was easy to resolve. I'm not sure about the slide, ours doesn't seem as bad as yours but we haven't driven through any serious rain yet. I hope in the Alaska monsoons we don't have an issue!

I'll be watching the forums and posting as we travel thanks to Starlink. I'm going to be doing a mod post in the next couple of weeks to show off all our tweaks to date, including Starlink mounted on the roof with a quick release adapter and outside access port if we need to move it away from the coach.
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Old 05-30-2024, 01:50 PM   #13
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I had hoped to be able to spend a full day doing the PDI, but with my wife still recovering from surgery and the 4 hour round trip that was just not really in the cards.


The dealer talked a good game about their "great PDI". But sadly the reality was that mostly likely all they did for the PDI was rinse off the MH, turn on the batteries and do a minimal check for leak


I knew it was highly likely that I would find a bunch of stuff, especially when I found 3 things within the first 5 minutes that they had missed that were obvious..


And given that their tech was pretty much clueless on the Xantrex Freedom system AND that he tried to gaslight me that the heat pump was working when it obviously wasn't outputting heat I would not really want to take it back there for warranty repairs.



I'm guessing that with your slide it is out by the same amount top to bottom. Is it out the same amount front and back or is it skewed?


I'm assuming that you followed the instructions on setting the limits and still have an issue.


In any case you will probably be OK as long as the seals are at least touching along the front of the slide when it is retracted. If there is a gap in the seals then keep a close eye on things to make sure that there are no leaks. If it does leak see if you can get some weatherstripping at a big box store to fill the gap until you can get to Dynamax.



I tried having a local "slim rack slide expert" come to do it here. But at the end of the day the tech got fooled by some camber that Dynamax puts in their sides to help seal better in the middle. The tech counted the gear teeth with the slide fully extended and pronounced it as fine. I should have caught that and had him test it with the slide partially retracted. When the slide is out fully it is equal top and bottom, but the bottom gear rack is bowed in and touching the slide box which per Lippert is not optimal. Bowing out is OK, but in doesn't give as much flexibility to the gear rack. Anyway with I counted the teeth with the slide half way in and again with about 6" to go. And I see it being off at least 1 tooth, and probably 2. On retracting as soon as the bottom rack relaxes the bottom is out 1/2" more than the top.


So much for "experts". And the one nearby FR dealer that COULD do the warranty work says it is a very slow process, and frankly I don't have a lot of faith in the local dealerships techs. Plus I figured that from what I've seen in the forums and Facebook if you really want it done right take it to Dyanmax. It's an 8 hour trip for us to Elkhart. They are estimating 2 days to take care of everything. Then we have an 8 hour trip to our daughter's in upstate NY. The Dynamax side trip only adds about 3 hours to our usual travel time to upstate NY. So not too bad.
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Old 05-31-2024, 05:54 AM   #14
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I can confirm that when I was doing my PDI at the dealer, I had pulsing lights as well when I was starting up the Truma Combi. I can also confirm it was when it was using diesel.

I did quick hot water test using Electric 2 w/o diesel at home and I didn't notice any flickering of the lights.

Right now its in storage for another month until I get back to PA for the summer. I will dig into this more then as well.
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Old 05-31-2024, 07:28 AM   #15
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It does appear to be a bit of a common issue.


We are due for service at Dynamax July 8th, and it is one ot the items on the list.



I understand that the engineers are working on a solution, so hopefully they may have something by the time we get there.


It's not the end of the world, but at least with ours it is a VERY pronounced strobe effect not just a brief or little bit of flicker.


I don't expect that it will have an impact on the AC power off the inverter, but I haven't verified that yet. I would expect that it likely isn't enough variance on the 12V supply to cause any inverter issues.
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Old 05-31-2024, 07:59 AM   #16
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It does appear to be a bit of a common issue.


We are due for service at Dynamax July 8th, and it is one ot the items on the list.



I understand that the engineers are working on a solution, so hopefully they may have something by the time we get there.


It's not the end of the world, but at least with ours it is a VERY pronounced strobe effect not just a brief or little bit of flicker.


I don't expect that it will have an impact on the AC power off the inverter, but I haven't verified that yet. I would expect that it likely isn't enough variance on the 12V supply to cause any inverter issues.
The light flickering is a DC power issue and not an AC power issue so the Inverter is not in play.

The only AC power used in the Truma Combi is the two electric elements. The fan and the glowplug are DC powered so I can see the glowplug causing the lights to flicker as it powers up to ignite the diesel.

My electric-only water heater test also comfirms it is a DC load causing the lights to flicker.
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Old 05-31-2024, 10:07 AM   #17
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Thanks,


Yes, I know that it is a DC issue. And not directly AC.


What I was musing about was that if the DC input to the Inverter is "noisy" would it have any impact on the Inverter operation. I suspect that it doesn't, but it is a question.


And related does it have any impact on other electronics that run off 12v. E.g. the radio as one example, assuming that the radio is powered from the house 12V and not the chassis.


Brian was saying that Truma suggested an isolated 30 Amp 12V supply.


But it unclear right now if the issue is that because the FireFly system shares the same 12V supply is there some noise introduced that impacts FireFly? Or something else.



Hopefully I'll find out more in July.
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Old 06-01-2024, 05:11 AM   #18
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Thanks,


Yes, I know that it is a DC issue. And not directly AC.


What I was musing about was that if the DC input to the Inverter is "noisy" would it have any impact on the Inverter operation. I suspect that it doesn't, but it is a question.


And related does it have any impact on other electronics that run off 12v. E.g. the radio as one example, assuming that the radio is powered from the house 12V and not the chassis.


Brian was saying that Truma suggested an isolated 30 Amp 12V supply.


But it unclear right now if the issue is that because the FireFly system shares the same 12V supply is there some noise introduced that impacts FireFly? Or something else.



Hopefully I'll find out more in July.

I highly doubt the DC input into the Inverter is noisy. I installed this same Inverter / Charger in my Super C about 3 years ago and know it and the wiring pretty well. For the DC input to be noisy there would need to be something in the battery compartment causing an issue and I just don't see it.

If you have ever owned any diesels before, you know the have glowplugs. They draw a fair amount of current before the engine is ready to fire. I can see the Flickering lights coming via the FireFly as the glowplug heats up to ignite the diesel in the Truma since the FireFly does have some communications with the Truma.

To me this is a minor nuisance and more of a non-issue. I don't see it having much of an impact on the DC power of the coach since the only time this issue is going to occur is when the Truma is heating the glowplug to fire up on diesel. Once the diesel is burning, the glowplug goes out and there is no further power demand for it.

I would just stay away from operating the levelers or slide while firing up the Truma on diesel. Otherwise the impact on the radio, USB chargers, etc. should be a non-issue.

Given Brian's description of the way things need to be wired for the shunt to provide accurate SOC information, I don't think the isolated 30A power is a good solution. And it sounds like it may be something more simple like a firmware change for the light voltage. I have also seen issues with LED lights on dimmer controls before and these lights are dimmable.
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Old 06-01-2024, 05:30 AM   #19
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Thanks,


I didn't expect that the inverter would be impacted, just trying to think about where the issue might be an impact.


I know that Brian also indicated that there might be a change that could be made related to the LED lighting control, so we'll see if that will help.


If you have similar flickering of the LED lights and don't find it to be excessive it may be that we have a slightly different issue. It is a very intense strobe effect when the Combi is starting up. But then I did see it once when I had turned off the Combi and it strobed the lights again while it was shutting down. As I mentioned that might be a race condition where the Combi was just starting the burner again, and using the glow plug, before it saw the shutdown command from FireFly.


I do have a diesel tractor, and of course the glow plug will use a lot of power, but with the tractor there is no feedback on the power being used.



If the strobe effect on the lighting is a known issue it would have been helpful for that to be mentioned in the documentation. At least then you would be aware of the root cause.


So based on your feedback and Brian's I'm hoping that perhaps some tweaks can be made to the FireFly configuration related to the LED lighting to at least minimize the strobe effect.
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Old 06-01-2024, 06:04 AM   #20
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If you have similar flickering of the LED lights and don't find it to be excessive it may be that we have a slightly different issue. It is a very intense strobe effect when the Combi is starting up. But then I did see it once when I had turned off the Combi and it strobed the lights again while it was shutting down. As I mentioned that might be a race condition where the Combi was just starting the burner again, and using the glow plug, before it saw the shutdown command from FireFly.
When I showed up at the dealer to begin my PDI the first time back in April, I would say it was somewhat more like a strobe effect and it was very noticeable. Enough so my wife was concerned.

When I went back to the dealer a month later to resume my PDI after they addressed the issue with Battery Pack A, I would say it was closer to flickering than a strobe effect.

Now one thing that could impact the amount of this effect is where your light intensity is set at the moment you are starting the Truma Combi. If you have the light intensity turned up to the max, the impact of the glowplug firing up may be less than if you already have the lights dimmed a little..... or dimmed a lot.

I can say that I was testing the dimmable lights so I very well could have had the light intensity at different settings when firing up the TC at different times.
It might be worth you adjusting your lights and then starting the TC to see how it impacts the lights at different settings. Perhaps it is more pronounced depending on whether the lights are set bright or dim.

I had a good idea it was tied to the glowplug heating once I got it home and wanted to test the hot water temperature only running the Electric Elements and there was no impact on the lights.

I also know it has nothing to do with the fan inside the TC because I ran the TC in Ventilation Mode and tried all of the fan settings. The TC can really push the air through the vents on high speed and there was no impact on the lights.


Good luck!
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