Deep fryer’s got issues

[fixbear]

You may want to check the drain valve switches that the valve has been placed all the way.  Also that the gas coupling is fully locked on.  And as with any fryer, high limit connections and wiring to the valves.

 

I believe that on the CFE’s, they use a hybred gas valve.  The pilot is millvolt and the main is 24 volt.

This may help to troublshoot

[ectofix]

As fixbear said, check to be sure the gas hose quick disconnect is fully seated.  If it’s not fully seated, it can pass SOME gas, but greater demand from all three fryers being on will starve all three fryers.  That can weaken the pilot flames enough to cause thermopile output to eventually drop below the minimum needed to keep the pilot valves open.

[olivero]

Hey Guys,

 

I checked the hose, its fully connected. It’s funny you mentioned it because I had a thing like that a couple of weeks ago and I was completely stumped, figured it could ONLY be the hose, so I gave it a shot and sure enough, it was only partially open, very odd.

 

So here’s my question, on the traditional “Zero gas pressure system” like Cleveland, Welbilt or whatever it is these days so graciously calls it. There is always a flame sensor of sorts, mostly that’s spark or hot surface ignition, they don’t really deal with the pilot ignition style so I am not too familiar with it.

 

What monitors the flame? How does it know the main gas valve is open and the main flame is on? It seems there is nothing there monitoring the main flame other than the temp sensor as the indicator light that tells you the fryer is heating will stay lit even if there is no main flame present.

 

I just asked the chef, he said everything went dead, pilot and main flame, had to relight the pilot and then it worked but died again after some time. 

 

I’ve removed the thermopile on the center one (its center and the right one having issues) and cleaned it off before when it was having issues with just the pilot going out, that fixed it.

 

So from what I get from this, the thermopile is what’s keeping the valve open, if that signal (minimum if 200 Mili Volts) drops, it won’t open the main valve which fuels the main flame, is that right?

 

I guess the part I don’t understand is what is the flame sensor here?

[fixbear]

The millivolt power from the thermo-pile is the monitor of flame. Problem I see is that a thermopile should be 750 millivolt.  If your dropping to 200, check the pilot flame to be correct and placed correctly on the generator. A minor amount of dust in the pilot orfice and air sytem will change the BTU output drastically.  There by changing the power output.

[olivero]

Okay, good to know. I haven;t measured it yet, the 200 milivolt was what Frymaster said to look for.

 

So regardless of what the big flame is doing, the pilot goes out, the main flame goes out as the valve shuts?

[olivero]

Okay,

 

I checked MV signal on both units, the one on the right is about 400 MV, I checked the center one, it was about 300, made the pilot a bit bigger and moved the thermopile closer to the pilot and it went to 500 MV.

[ectofix]

You voltages look good then.  Just be sure there’s no voltage drops across the connections to the combination valves.

 

NEXT – sit, watch and monitor.  Monitor fryer temps.  Monitor thermopile voltages.  Make sure those aren’t slowly dropping and the fryers aren’t overheating.  Frymaster’s high-limits trip at around 425 degrees and automatically reset at around 350 degrees.

[olivero]

Okay, So I’ll go see when they are cooking with it later today.

 

Thanks for the help guys.

[fixbear]

Olivero, it’s not unusual for the firing rate of a pilot to change in a high volume kitchen and cause trips.  I had a customer that I could reliably recieve a call from every couple of months for vulcan ovens. They bring in all the stock twice a week right down the line and at the end of the line was where the driver dropped it.  Next to the ovens. The kitchen would then break the boxes down and store the supplies right there.  Cardboard dust fibers would accumulate in the pilot air intakes changing the mixture. Hydraulic valves are very sensitive to temp,  so one side or the other would quit. It got where every 2 mouths I would just pull and clean the pilots for the heck of it if I was near..

[olivero]

interesting, that is also something I can check if needed, thank you for the information.