Almot wrote:
pnichols wrote:
We retreat inside our RV and use physics by slightly pressurizing the interior so that no generator fumes can enter.
You still need air coming from outside. Filters on RV systems are not what people might think. To filter the fumes out, a filter has to be at least 12 MERV rating, it's a bulky cartridge. You can find it sometimes in HVAC systems of upscale buildings or hospitals but not in RV.
Generator exhaust fumes stay low - certainly lower than the top of our 11'3" roof.
Given that, to maintain pressure inside the rig we close every opening EXCEPT one fan powered roof vent. We switch it's fan to AIR IN and set the fan's speed to LOW. Very little air from up above can actually flow into, or through, our rig because every opening is closed. What this fan set up is doing is merely maintaining a low positive pressure inside the RV so that no gases can enter anywhere below the roof line, including small cracks, etc..
I suppose if we were surrounded on all sides by folks using Gen-Turi stacks ... all with running generators ... that some ultra small amount of generator fumes could eventually work their way in from our up-high positive pressure roof fan. But the chances of that scenario with our non-event style of camping is zero.
This coach pressurization method has worked like a champ for road dust and all fumes. However, the pressurization intake point must be as high as possible. Off-road caravans in places such as Australia sometimes have this system capability built-in, but those systems must have filters for the pressurization fan intake because those caravans seldom have intakes way up high due to their roof heights being much lower than those of Class C motorhomes.
