All our fleet of scanias has a warning on the fuel tanks saying the night heater must be switched off at least 3 minutes before entering a fuel station. I always do, but what’s the reason for it? I appreciate you wouldn’t want it on while you fuelling up just like you wouldn’t have your engine running, but what’s the significance of the warning saying to turn it off at a specified point before fuelling?
Hot exhaust + fumes = KABOOM
They take a few mins to spool down once they’ve been turned off, same as why it takes them a few mins to start blowing warm air when they’ve been switched on.
At a guess, I would imagine that it is to ensure it has completed the run-down cycle before you start refuelling. The primary reason you shouldn’t run a night heater while fuelling up is not so much to do with safety as much as that the crud in the bottom of the tank gets stirred up and could get sucked into the night heater, blocking the filter, or so I’ve been told.
Honked:
Hot exhaust + fumes = KABOOM
Nah, I don’t buy that’s the reason. Everyone would be pushing their cars onto the forecourt if that were the case (exhausts). I go with Harry’s theory 
Urban Myth, like “Using your mobile phone at the petrol station can cause an explosion”.
The concentration of fumes can get quite high around where the nozzle goes into the vehicle for sure - but we’re talking about PETROL here.
Diesel kinda has to be “forced” to burn. You can wick it or spray it - but just lying about, it’s no easier to light than a block of candle wax.
Rowley010:
All our fleet of scanias has a warning on the fuel tanks saying the night heater must be switched off at least 3 minutes before entering a fuel station. I always do, but what’s the reason for it? I appreciate you wouldn’t want it on while you fuelling up just like you wouldn’t have your engine running, but what’s the significance of the warning saying to turn it off at a specified point before fuelling?
Never turn mine off,could be only a matter of time before I go sky high!!
Hate night heaters with a passion burnt my hand on one a few months ago because some ■■■■■■ had taken the plastic cover of and left the exposed metal…
How many of you turn your mobile phone off or unplug your 12 and 24v adapters each time you fill up? ok yeah they can still carry an electric charge for at least 5 mins after the engine has been cut, but I remember watching some health and safety video about do’s and don’t when filling up and someone stated that you shouldn’t fill up near any heat sources, what about the engine? do you wait for it to cool down?
Why does anyone have the night heater on when driving??
DaveTheMinion:
How many of you turn your mobile phone off or unplug your 12 and 24v adapters each time you fill up? ok yeah they can still carry an electric charge for at least 5 mins after the engine has been cut, but I remember watching some health and safety video about do’s and don’t when filling up and someone stated that you shouldn’t fill up near any heat sources, what about the engine? do you wait for it to cool down?
No, don’t be utterly ridiculous.
A.
It’s a conspiracy, they’re trying to control your mind.
Extreme arse covering by the manufacturers I’m afraid. Can’t ■■■■ these days without a risk assessment.
One day in the near future we will need a movement order just to take a dump.
Take no notice and crack on…
[The poster of this comment accepts no liability for any injuries sustained by following his instructions.
Any reference to ■■■■■■ positions is unintentional and in the mindset of the reader.]
Freight Dog:
Honked:
Hot exhaust + fumes = KABOOMNah, I don’t buy that’s the reason. Everyone would be pushing their cars onto the forecourt if that were the case (exhausts). I go with Harry’s theory
Its science really, Hot air and exhaust fumes go up, and petrol and diesel fumes, are heavier then air, so go to the ground. That’s why they have those little grids on/around every forecourt
I often wonder how I’ve got to 46 in one piece. If your driving around with your night heater on your either mental, agency, cold or have pressed the button accidentally. Risk is minimal so don’t worry about it.
tommymanc:
Freight Dog:
Honked:
Hot exhaust + fumes = KABOOMNah, I don’t buy that’s the reason. Everyone would be pushing their cars onto the forecourt if that were the case (exhausts). I go with Harry’s theory
Its science really, Hot air and exhaust fumes go up, and petrol and diesel fumes, are heavier then air, so go to the ground. That’s why they have those little grids on/around every forecourt
My point exactly, which is why they don’t care too much about combusted exhaust emissions and why one can drive a car onto a forecourt
Night heaters when running do not dump ambient temperature fuel vapour onto the floor from the exhaust duct?
Pretty sure that Scania are referring to the fuel filter heating system which you are supposed use in sub-zero temperatures to stop the diesel thickening, not the night heater. That is how I have always read this warning sticker the OP was referring to.
Adonis.:
DaveTheMinion:
How many of you turn your mobile phone off or unplug your 12 and 24v adapters each time you fill up? ok yeah they can still carry an electric charge for at least 5 mins after the engine has been cut, but I remember watching some health and safety video about do’s and don’t when filling up and someone stated that you shouldn’t fill up near any heat sources, what about the engine? do you wait for it to cool down?No, don’t be utterly ridiculous.
A.
I agree with you, I am only quoting what was said in the HSE training video, the same one that stated getting in and out of your vehicle while filling up can cause a build up of static that can ignite fuel fumes, same goes for the Using a mobile phone at a filling station! experts say you can use them and some say you shouldn’t, its not the ringing of the phone, the risk is in dropping your phone, again I cannot confirm this as one I do not use a phone when filling and Two I don’t wanna drop my phone 
Yes Ive found that diesel does tend to explode!!
What a load of bollox.
Easy, if you got to the forecourt without killing several cyclists and fumigating the country and susurvived the non indicating BMW drivers there is no need for having the night heater on.
On a lot of scania turn your blower control to the bottom setting, you will see a little green light come on (when the keys are out of the ignition) and it will use the engine heat to keep your cab warm while you g url yp/eat your pasties 