Atosa propane fryer

[ARK Cooling]

Need help. Ran across an Atosa propane Fryer today. It seemed to work fine but when the stat would turn the gas valve off I would get some flame puff at all four nozzles. The gas pressure was correct at 10 inches of water column, the flame was blue and not Smokey, the unit was venting well. The burner cell baffles had some age / wear and would glow orange I noted. The nozzle orfices were clear as the burner holes. Why the puff of flame at the nozzles when gas valve goes off ?
The manual says nothing about it and the tech line people have no clue. I get the impression they know very little about hvac. Any ideas ? The burners are cast iron and I see no air adjustment that could be made.

[VTP99]

Was it shipped as propane or converted ?

[VanMan812]

Propane can be difficult in a commercial kitchen setting. Some issues customers just have to deal with.

By flame puff do you mean there’s a poof/flash/bang at the orifice/burner entrance when the stat satisfies?

Or flame puff... a little candle-like flame at the tip of the orifice when the stat satisfies?

Was the gas pressure measured dynamic?

If it is candle-ing the gas valve needs replaced. If it’s flashing at the burner base that means the flame is following the fuel back down the burner. LP is heavier than air so the remaining LP has a hard time rising through the burner into the heat exchanger after the valve closes. A good clean system (burners, heat exchanger, baffle, flue) is important to prevent this. Sometimes a gas valve won’t snap closed and you might get this symptom. Usually an air adjustment will fix this but you say there isn’t one. I’d try to pull the burners and blow through them with nitro and see what comes out. Also pull the baffles and see just how bad they are.

[ARK Cooling]

It was shipped as propane.

[ARK Cooling]

VanMan, it is a poof or flash at the orfice. I measured the gas pressure with the gas valve on and downstream so it was not supply pressure. I think that's what you mean by dynamic. The orfice and burners are clean. I'm hanging my hat on propane is heavier than air and not rising out of the burner. I knew propane is heavier than air and natural gas lighter but didn't make that logical connection. Thanks....I suspect all propane fryers are prone to this. I see natural gas usually.

[VanMan812]

ARK, yep that’s what I meant by dynamic. Sounds like you covered your bases. From my experience the ambient temp and RH will effect if there’s a flash back flame at all and if there is flash back how frequent. That and age. Older LP fryers tend to flash more often which I think is due to fuzz/dirt buildup and lazy gas valves that don’t snap shut.


Sent from my iPhone using Tapatalk