I'm parked at an RV park in Las Vegas. Next to me is an older Marathon Motorhome. It's warm outside, so AC's are running, not heaters LOL. I've been stting outside I keep smelling diesel fumes........the generator is NOT running. However something in the nose of the motorhome is cycling on and off about every 5 minutes or so. Whatever it is, is very quite running and is smooth running.......nothing like a combustion engine. More like an AC unit, but quitter, and like I said, it's in the front and down low. Any idea what is running? I don't know if this is where the fumes are coming from either. If not, any idea where they might be from? ThanksBrian

It might be a fuel cell? Those can run on diesel fuel. Also diesel 3 cylinder engines are pretty quiet, sometimes less noise than the A/C units that they are running. .. My first thought might be a aqua hot system, but those are normally on the side of the RV and only run a few minutes to warm the boiler to 160F, then shut off until the showers are down, and the water cools. Good luck,Fred.

No, it's not a generator, the generator on this one is mounted about midway back. What's a fuel cell? I was wondering about the aqua hot, but why would it keep cycling on and off every few minutes, especially in this heat. Actually I don't even think there's anyone in it this evening. The motorhome is also plugged into shore power.

Fuel CellFuel Cell for Truck Camper

supercub wrote:No, it's not a generator, the generator on this one is mounted about midway back. What's a fuel cell? I was wondering about the aqua hot, but why would it keep cycling on and off every few minutes, especially in this heat. Actually I don't even think there's anyone in it this evening. The motorhome is also plugged into shore power.I think it's the Aqua hot system. Maybe they are washing clothes, dishes or taking a shower? The Aqua systems also heat water as well as provide heat for the interior.

What's running? | Good Sam Community

Golden_HVAC
Explorer
Apr 21, 2015
It might be a fuel cell? Those can run on diesel fuel. Also diesel 3 cylinder engines are pretty quiet, sometimes less noise than the A/C units that they are running. ..

My first thought might be a aqua hot system, but those are normally on the side of the RV and only run a few minutes to warm the boiler to 160F, then shut off until the showers are down, and the water cools.

Good luck,

Fred.
supercub
Explorer
Apr 21, 2015
No, it's not a generator, the generator on this one is mounted about midway back. What's a fuel cell? I was wondering about the aqua hot, but why would it keep cycling on and off every few minutes, especially in this heat. Actually I don't even think there's anyone in it this evening. The motorhome is also plugged into shore power.
gbopp
Explorer
Apr 21, 2015
Fuel Cell

Fuel Cell for Truck Camper
67Cutlass
Explorer
Apr 21, 2015
supercub wrote:
No, it's not a generator, the generator on this one is mounted about midway back. What's a fuel cell? I was wondering about the aqua hot, but why would it keep cycling on and off every few minutes, especially in this heat. Actually I don't even think there's anyone in it this evening. The motorhome is also plugged into shore power.

I think it's the Aqua hot system. Maybe they are washing clothes, dishes or taking a shower? The Aqua systems also heat water as well as provide heat for the interior.
fla-gypsy
Explorer
Apr 21, 2015
Water heating system
bluwtr49
Explorer II
Apr 21, 2015
I'm betting it's the hydronic heating system just keeping the coolant temp topped off. Depending on the system it holds at ~190 F give or take with either a combo of electric and diesel or just diesel.
Mr_Mark1
Explorer
Apr 21, 2015
supercub wrote:
I'm parked at an RV park in Las Vegas. Next to me is an older Marathon Motorhome. It's warm outside, so AC's are running, not heaters LOL. I've been stting outside I keep smelling diesel fumes........the generator is NOT running. However something in the nose of the motorhome is cycling on and off about every 5 minutes or so. Whatever it is, is very quite running and is smooth running.......nothing like a combustion engine. More like an AC unit, but quitter, and like I said, it's in the front and down low. Any idea what is running? I don't know if this is where the fumes are coming from either. If not, any idea where they might be from? Thanks
Brian

Marathon puts an air condiitoner behind the bumper (they will flip down)..... I think they call it a 'cruise air'.

Some Prevost coaches use a combination of cruise air and roof air. Bus air is usually in a side compartment with a large vent and mainly used when rolling down the road. You cannot get bus air with four slides, you will only have roof air.

MM.
Bigdog
Explorer
Apr 21, 2015
I was camped next to some folks like that, but he had an exhaust pipe on his. It was hooked up to his hydro hot and his wife complained about the fumes when it was running. It sure made it nicer for us next to him too. She was doing a wash and you could hear the machine cycling on and off.
cross_country
Explorer
Apr 21, 2015
maybe an aux air pump keeping it level?
Jim1eddoc
Explorer
Apr 21, 2015
since they are next door, why not stroll over and ask? If you mention you smelled gas, I don't think they would mind, and it might make them consider using a ducting unit to help out the neighbors.