Dometic fridge auto selections

[booster]

Originally Posted by Davydd

This is all getting confusing. We pull up to a service station and worry about propane being on or off. Propane does not ignite gasoline or diesel fuel. Electrical ignition does that. So to be safe couldn't you leave propane on but be required to shut down your electrical systems? Given that, wouldn't it be just as dangerous to start a car at a service station? It is beginning to sound if everyone has it backwards.

It seems the danger lies with a faulty propane system which could rear its ugly head at anytime or in the case of an accident. The accident factor would dictate prudence in turning off the propane at the tank.

If you go back to the original posts and questions, it was stated pretty much that way. Would the frig try to light and start a fire? Yep the electric, gas off or not.

I would say gas on, electric off is much safer the gas off, electric on.

The gas station rules were probably written before anybody in an RV even knew what an ignite was, so they only worried about existing flames, which would go off with propane shut off. Having the propane off does temporarily limit the amount of fuel available for a fire if one does start.

Cars starting, arcing, and people generating static sliding in and out of the seat seam to be the most common causes of gas station fires, but only California (I think) captures the fumes as you fill the tank. Don't know how they would be able to not have start the car to leave.

[Mike]

Originally Posted by booster

I would say gas on, electric off is much safer the gas off, electric on.

Me too.

Originally Posted by booster

The gas station rules were probably written before anybody in an RV even knew what an ignite was, so they only worried about existing flames, which would go off with propane shut off. Having the propane off does temporarily limit the amount of fuel available for a fire if one does start.

The igniter internal combustion engines all have is the spark plug. That's why the very first rule at the pump is almost always "turn off engine before refueling". Then the rest, no open flames, no cell phones, don't re-enter vehicle while fueling, don't fill containers on the vehicle - place on ground, all the static electricity spark/arc related stuff.

Originally Posted by booster

Cars starting, arcing, and people generating static sliding in and out of the seat seam to be the most common causes of gas station fires, but only California (I think) captures the fumes as you fill the tank. Don't know how they would be able to not have start the car to leave.

Once the pump is shut off, and refueling is complete, I guess they had to bite the bullet and assume you didn't spill fuel into your engine compartment, and it's probably safe to start the engine to drive away. I'm sure no one thought about the extra "engine compartments" on the average RV.

I've refilled across the river many times, and in colder weather have observed people refueling with their engines running, probably to keep the cabin heater running. The attendants should probably shut off those pumps immediately, but they don't for reasons unknown. Probably/maybe they don't notice, or just want to avoid a confrontation. However "while refueling" engine off is the law, afaik.

[Davydd]

Is refueling at a diesel pump safer?

[Mike]

Generally, probably, yes. At a truck stop, or other fuel station, using the diesel only pump islands.
If you're refueling your diesel (compression ignition) engine vehicle beside someone who is pumping gasoline into their (spark ignition) vehicle in an unsafe manner, you're still at risk.

[teachergal]

My dad said that diesel fumes are less volatile than unleaded fumes. He has a large 36' diesel pusher RV, he fills up in the truck lanes (he has a 100 gallon tank!) and the truckers don't even turn the engines off when they re-fuel. He did say that for me filling up the car lanes that it doesn't matter that diesel isn't as volatile, because there are folks right there filling up with unleaded.

[AmCruiser]

Diesel has a much higher flash point (130-160 deg F) than gasoline (-25 deg F) making it much safer than gasoline around ignition sources. Basically, flash point is the lowest temperature at which a fuel will vaporize into a flammable gas. Back in my merchant marine days, we used a diesel soaked rag on the end of a long torch to light the ship's boilers. We had a pipe welded vertically to the deck, full of diesel oil that we stored the torch in. When it was time to light off the boiler, we would start the force draft fans, cut on the atomizing steam to the burner, light the rag on the torch and stick it in the furnace next to the burner nozzle and crack the fuel valve. Once the burner lit, we withdrew the flaming torch and stuck it back in the pipe full of diesel to extinguish it. This in a 120 deg F engine room - hot, but still below the flash point of diesel.

That said, if the gas station island handle both diesel and gasoline, there is still significant danger because gasoline vaporizes into a flammable gas all the way down to -25 deg F.
Randy

[Mike]

Originally Posted by teachergal

My dad said that diesel fumes are less volatile than unleaded fumes. He has a large 36' diesel pusher RV, he fills up in the truck lanes (he has a 100 gallon tank!) and the truckers don't even turn the engines off when they re-fuel. He did say that for me filling up the car lanes that it doesn't matter that diesel isn't as volatile, because there are folks right there filling up with unleaded.

Your Dad is a wise man.