My experience is from Truma, but will most likely be the same with any other blown air heater. Might also including systems like Alde, but as they are slower to react (heat) it's maybe not something affecting those kinds of systems. I've been meaning to write this years ago, but now as I've had the same problem (and fix) on two diffrent vans, I may really be on to something so I thought I'd share this now.
Our previous PVC was a Hymer 2011 with 4kw gas Truma. In the autumn when the temperatures started to be around 0c I noticed that heating was kind of shit. Especially the hysteresis was enormous, I believe it was even up to 5 degrees. Meaning the temperature fell very low before the heater started to do what it's meant to. Also, every time something was cooked, the heater went to low power or even shut down completely. Everone knows how quick you get the chills if it's 0c outside ant the heater decides to take a break.
Our current van is a Hymer PVC 2024 with a 6kw diesel Truma, and even before we got it I noticed on youtube videos that yep, same idiotic design still. When the van came and summer turned in to autumn, the same idiotic behaviour of the heater. Exactly the same problem as with the previous one. I was furious even if I knew it was coming. Why do they keep doing it this way!
With the first van I quite quickly thought it has to do with the placement of the temperature sensor. It was above the sliding door (LHD, slide on the right) and when you cook something the heat goes there and the heater think it's warm and no need to heat. Also, as warm air goes up, the heater was satisfied with it's work eventhough there was much colder on the lower level. At this point I also noticed that some manufacturers place the sensor significantly lower, and that's what I ended up doing.
Took the sensor away from the original place up high and placed much lower and oh my god. It was like a completely new heating system! Temperature stayed much more constant and cooking made no difference any more. Naturally when you're boiling potatoes for 45 minutes the temperature goes slightly up but that's much easier to deal with. The much more even heating did increase the gas consumption quite noticeably, but I never thought of reverting back to the old system.
And as with the new van, even sillyer design. The sensor was just behind and above the driver's head, so in addition to the same problems as with the older, this also made the heater to usually turn off while driving as the sensor got heat from the car's heater and thought all ok no need to heat. That then leads the living area getting cold as well as all the water systems. With this van there were slight problems with the modification so I ended up getting it done only in February, and oh boy was I pissed on my trips until then. But when I got it done, it's been pure perfection ever since.
So, if your heater doesn't work quite as you'd expect and the temp sensor is high above, you might consider this. Just make sure it's positioned that way that it doesn't get any direct - or hopefully not even indirect - heat blown in to it, that way it's probably going to get even worse
In the picture you can see the approximate positions I've used. The green is the new one, didn't really want to go that low but it was the easiest place to try so I went for it and works just fine.
And yes I'm pretty sure there are people who have their sensors high and feel it works just great, guess the manufacturers wouldn't keep doing that if it didn't work. But from my experience I don't get it.
Our previous PVC was a Hymer 2011 with 4kw gas Truma. In the autumn when the temperatures started to be around 0c I noticed that heating was kind of shit. Especially the hysteresis was enormous, I believe it was even up to 5 degrees. Meaning the temperature fell very low before the heater started to do what it's meant to. Also, every time something was cooked, the heater went to low power or even shut down completely. Everone knows how quick you get the chills if it's 0c outside ant the heater decides to take a break.
Our current van is a Hymer PVC 2024 with a 6kw diesel Truma, and even before we got it I noticed on youtube videos that yep, same idiotic design still. When the van came and summer turned in to autumn, the same idiotic behaviour of the heater. Exactly the same problem as with the previous one. I was furious even if I knew it was coming. Why do they keep doing it this way!
With the first van I quite quickly thought it has to do with the placement of the temperature sensor. It was above the sliding door (LHD, slide on the right) and when you cook something the heat goes there and the heater think it's warm and no need to heat. Also, as warm air goes up, the heater was satisfied with it's work eventhough there was much colder on the lower level. At this point I also noticed that some manufacturers place the sensor significantly lower, and that's what I ended up doing.
Took the sensor away from the original place up high and placed much lower and oh my god. It was like a completely new heating system! Temperature stayed much more constant and cooking made no difference any more. Naturally when you're boiling potatoes for 45 minutes the temperature goes slightly up but that's much easier to deal with. The much more even heating did increase the gas consumption quite noticeably, but I never thought of reverting back to the old system.
And as with the new van, even sillyer design. The sensor was just behind and above the driver's head, so in addition to the same problems as with the older, this also made the heater to usually turn off while driving as the sensor got heat from the car's heater and thought all ok no need to heat. That then leads the living area getting cold as well as all the water systems. With this van there were slight problems with the modification so I ended up getting it done only in February, and oh boy was I pissed on my trips until then. But when I got it done, it's been pure perfection ever since.
So, if your heater doesn't work quite as you'd expect and the temp sensor is high above, you might consider this. Just make sure it's positioned that way that it doesn't get any direct - or hopefully not even indirect - heat blown in to it, that way it's probably going to get even worse
In the picture you can see the approximate positions I've used. The green is the new one, didn't really want to go that low but it was the easiest place to try so I went for it and works just fine.And yes I'm pretty sure there are people who have their sensors high and feel it works just great, guess the manufacturers wouldn't keep doing that if it didn't work. But from my experience I don't get it.
