L.P. burner in deep fryer sooting

Solid_Fuel_Man

Went to order pizza at a local mom&pop yesturday (that I also do some work at) and as I was waiting for it to cook the owner asked me to check out their new fryer. Unit is an Imperial 1F-S-40.

Old one caught fire and was electric. Gas company installed this new one 3 weeks ago.

She asked if flames from the chimney were normal, as I noticed heavy sooting there as well. Classic NG not converted to LP I thought....those slobs didn't catch that? It was slow, so I opened up the access door and turned up the thermostat, to a nice woooosh and big lazy yellow flame. Data plate stamped LPG and LPG stickers on gas piping... factory screw up?

Well I returned today with the work van armed with the tools to get to the bottom of this. Manifold pressure per data plate 11"wc, and #51 orfaces for L.P. also the millivolt pilot was quite large, but no yellow tipping. Set everything to data plate spec, cleaned the soot out of HX, and still very lazy flame. What am I missing here? Could the wrong gas valve be installed? I played around and set the manifold pressure to 5"wc and still yellow sooty flame. Also set incoming gas pressure to 11.5"wc, and turned down pilot to normal size.

The burners were the same for both NG and LP, with no air adjustments. What am I missing? Calling Imperial tomorrow for parts verification.

JUGHNE

Is it connected to LP or NG?
If NG is it a pounds system without reg at fryer?

The old one was electric?
This is probably under a powerful hood.....how about make up air for the gas burner?

Solid_Fuel_Man

It is connected to LP. No difference with hood on or off. They are closed Monday's so I had the place to myself and there is plenty of makeup air. Very old drafty building, plus I propped an exit door to be sure. I was thinking same thing.

JUGHNE

How many burners on this?
#51 will pass 31,357 btuh @ 11.0 WC LP

What is the nameplate input rating?

Steamhead

Has to be either too much fuel, not enough air or the flame is impinging on something. How do the exhaust gases get out of this thing?

Solid_Fuel_Man

@JUGHNE nameplate states 105,000 btu. 3 burners fire into slightly tipped up firetubes with a simple baffle that you can see in the pic. This is after I brushed it out.

@Steamhead these firetubes just open into a collector and exhaust gasses rise up and out the back. You can see in this pic the sooted sheetmetal where the flue gasses exit out the back.

Harvey Ramer

Did you check the draft?

Solid_Fuel_Man

Not sure how I can check draft. Not really any place to use manometer, pretty much open combustion. I may be able to find somewhere in the back to connect manometer.

As a side note, when I blow gently into the air mix venturi the flame blues up well and looks like I'd expect for a 33,000 btu burner.

I.can get more pictures of the cast iron burners if you'd like. I removed them for casting numbers to check if they were the correct ones for L.P.

JUGHNE

I would call the manf. company. There must be someone there in the know.

Does it look like any panels might be missing to create a draft for more air into chamber? WAG

EBEBRATT-Ed

seems like an air or draft problem to me

JUGHNE

Did the mystery of the fryer get resolved???

Solid_Fuel_Man

No, I've been out of work with a severe back injury.... have not been back. I should call manufacturer as I have nothing else to do. All caught up on paperwork and billing though!

mcfall

i used to work on restaurant equipment. there are a few things i would check. with LP the supply line needs to be smaller and it needs a regulator. the exhaust hood is irrelevant. it either works or it don't. but typically the tech service dept will walk you thru it.