vulcan deep fryer LG400 propane a food trailer.

[ectofix]

Steven wrote,

Any comments to confirm this is the problem. Baffles do look like they over heated at some time and are warped.

Impossible to confirm without being there looking at it myself.  The baffles diffuse the flames so they impinge on the heat exchanger tubes.  If they’re in bad shape, my mental picture tells me that they could cause such a problem. 

Here it is.  You’d need four of them:

Vulcan Hart 00-417008-000G1 BAFFLE ASSY | Parts Town 

 

I don’t know what a cheap fryer go for nowadays, but sure seems that your price for four of those will come really close to the cost of a new cheap fryer.

[fixbear]

Key here is the mobile application.  Operating on portable tanks,  sloshing oil, un-level,  and I suspect small  crimped regulator.  With a elongated ring burner, there is no way to have flames out the flue unless the mixture is way off or a additional fuel is added after the burner.  ie; oil down the flue from movement.   Which also means a quick build up of carbon in the flue.  Baffle damage may block the flue flow, but with that type of burner you would have roll out inside.

 

One should put a manometer on the burner line.  verify the pressure and nozzle size.  I have found portable installs the worse to determine problems with. As with each location change the variable’s increase dramatically.  Also look real close to the regulator venting.  That will cause this. The fuel supply is constantly changing due to the gas tank valve being turned off and on each location and bottle changes. Also the POL fittings and regulators are a limited flow for the application.  Black is low flow, Under 100,000 BTU’s.   Green can be a medium flow, up to 250,000 Btu.  This fryer is 120,000. So it has to have the green or the old wrench on with a 165,00 regulator.. (closest to that capacity in a portable configuration)

 

Knowing what I have seen with portable operations,  I would want to see the overall install and do a evaluation right from the bottle to the flue. As well as usage review.  Down time storage can also be problem with different pests looking for a home.