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Fryer suddenly stopped firing
I just bought a used natural gas fryer. I hooked it up to the line (made sure it didn’t have leaks), then lit the pilot and fired it up. I repeated the ON/OFF a few more times to make sure it was working fine.
Then I started filling the fryer with hot water and griddle cleaner, intent on boiling off the previous owner’s grease.
once filled I tried firing it up and all I get is the ‘click’ of the thermostat! no fire anymore!
the pilot is lit and the three secondary pilots (at the base of the tubes) are also lit, but it won’t fire up the main burners anymore.
so I had an appliance guy come and switch out the thermostat cuz he figured it just died on me. after switching it to a new thermostat, nothing changed. pilots are lit, but main burner won’t ignite. he is stumped as well.
Anyone got any ideas? I tried adjusting the gas pressure screw and no change.
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20 Replies
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It would be very helpful to know the brand, model and serial number.
There are multiple possibilities here. If the unit was dry fired (no oil in it) it is possible that the hi limit is tripped. You could have a faulty thermocouple (or thermopile). The gas valve could be bad. Gas pressure is important and needs to be adjusted properly. The unit data tag should tell you the correct pressure.
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One should never dry fire a fryer. Tends to crack the fry chamber. Also when one is moved the burner section should be inspected. Especially if it has infrared plates.
Not knowing your brand or model number puts me at a handy-cap. But lets assume from your description that you have a pilot machine with self generation thermopile. Being the pilot remains lit, Your safety is closed and the thermopile is making some power. Before replacing any parts one should know what the problem is by using a DVOM. This requires one to know what the system has and how it works. I’m going to out on a limb here and explain a very basic fryer control system, but do not assume this is yours till you check the make , model and service manual or wiring diagram inside the door.
Stand alone non powered fryers use a 750 millivolt thermopile that makes power when heated. The pilot coil of the gas valve will be in series with the high limit reset. And one should have a minimum of 580 MVDC at the valve. The valve terminals will be marked with common, pilot, and main valve. Thermopile and safety will go to the common and pilot. Now the pilot terminal will have a second wire going to the thermostat. And to complete the circuit a wire coming back to the main valve from the thermostat. The common internally is wired to both coils of the valve. Measure the voltage across the pilot and common terminals with the pilot lit and the thermostat off. Turn on the thermostat and note the voltage drop. It should drop about 50 millivolts. If it doesn’t, it’s your wiring or thermostat. If the voltage is below 450 mV, either the millivolt generator or the pilot flame is not correct or you have a resistance is the pilot, safety circuit.
This is just a basic. You may also have interlocks for drain valves or tank fill. Even flame rollout safeties. All depends on make and model.
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Most common here is the wire connections
And I forgot to mention melt features for the use of shortening.
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thanks for the replies,
The gas pressure on the line is correct for this fryer because it is replacing a similar fryer with same pressure requirement.
Ever Since the “repairman“ tried changing the Thermostat for a new one, and reinstalled the old one (because the thermostat wasn’t the problem), now the pilot won’t stay lit. no matter how long I keel the button depressed and ease off slowly, the second the button is up the pilot goes out.
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Never heard of MKE. Is that some cheap, foreign-made product?
FWIW: The wiring in that fryer looks atrocious. I’d be checking all the connections first. THEN the gas pressures. BOTH – supplied to the fryer AND the main burner manifold pressure. Your ORIGINAL problem could have been something as simple as a clogged regulator vent.
You said the gas pressure is fine because it replaces one just like it.
What was wrong with the one you replaced?
That fryer was previously a LP fryer per the data sticker, but someone scratched it out & scrawled “NAT” on it with a Sharpie.
Who converted it to natural gas?
That appears to be a VERY basic millivolt fryer that a QUALIFIED service technician could quickly and easily troubleshoot and solveyour problem.
Sounds like you need a new repairman.
We can’t diagnose your problem from pictures and your description since we’d needing to know gas pressure and voltage readings at specific test points to narrow it down.
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I can’t believe no one caught this little tidbit:
>the pilot is lit and the three secondary pilots (at the base of the tubes) are also lit
And I haven’t worked in 2 years. Yall should be ashamed. 🙂
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@badbozo2315! Good to see ya!
Are you saying that his description of three secondary pilots is actually the main burner orifices candling?
Well…DUH! I was picturing something like a zip tube (such as Keating pasta cookers) when I brushed over that statement.
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Yeah, I was also like MKE? But when I saw the photo of the single pilot assembly, and the odd burner tubes, I knew what was going on.
If I was on this job, I would have spec’d a new NAT gas combo valve, new high limit, test the tstat, and removed the aparently unneeded extra in-line regulator.
Unfortunetly, depending on the travel charge, it might be cheaper to roll this one to the dumpster and buy a new Dean or something.
And aparently MKE makes (or resells with their name on it) a whole bunch of stuff. I didn’t research much though, to try and find the parent company.
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Ha! MKE had a bankruptcy auction a week ago. 🙂
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Yes, I found that too.
MKE shuttered their doors this past Oct. Employees showed up for work one day to be told they’re bankrupt, to grab their personal possessions and go home.
Some folks had worked there nearly forty years.
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Based upon our resident badbozo’s statement, you definitely need to get a properly qualified technician to look at that fryer. I’m suspecting issues with either from improper incoming gas pressure problem…or that grease-ladened combination valve.
Ihave concerns over whether your fryer was properly converted to natural gas.
BTW: IF there is a line-installed gas regulator feeding natural gas to that fryer…and your building’s supply pressure tests at 1/2psi or less, then it is within the proper input range of that fryer’s Honeywell valve. So… the line regulator can be eliminated.
Run this past your NEW service tech. He/she should understand what I’m saying.
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thanks again for the help;
There IS a gas regulator on the line.
The gas pressure requirement on the “new“ fryer is the same as the old one, so I assumed I could just hook it up without touching the regulator.
what baffles me is that after I hooked it up it was working. I tested it 4-5 times to see if it was firing. I only let the main burners burn for less than 10 secs each test. The only weird thing I noticed was that there was a 2-second delay to hear the Whoosh/whoop of the main burners firing & it sounded louder than what I’m used to. Also after I turned the Thermostat all the way down, the burners would go OFF like they should except the three columns still had a candle lit as well as the pilot.
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So since the technician tried replacing the thermostat, the pilot light will not stay lit.
ruling out the thermostat, there is no reset button for the Hi-Limit. I cannot keep the pilot lit. I have even tried increasing the gas pressure both from the gas line regulator and from the combination valve (both have since been reset to where they were before), this incurred no change in flame intensity nor did it keep the pilot from going out once you release the pilot knob on the combination valve.
maybe the thermopile is now defective, but before he changed the thermostat the pilot was able to stay lit.
I’m stumped.
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That would have been the first thing to change, the thermopile. Clean the pilot out and verify the thermopile is generating the proper amount of DC millivolts. Make sure your connections at the gas valve terminal block are clean and tight, greased and loose connections will drop the millivolts.
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Here’s a manual. There’s a schematic on the last page.
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Sounds like the wiring got disturbed during the replacement.
One should never guess with gas pressures. You’ll need a manometer to measure whats happening and to calibrate the valve. But what disturbs me most is that the burners continued to burn a candle flame after shut off. That means your going to have to replace the combi valve for safety reasons.
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Ok, so I decided to open up the Hi-Limit since it has no visible reset button. inside is a little button that isn’t meant to be pushed manually, but I pushed it anyway.Â
it made a small click sound and it produced an audible click within the combi valve.Â
Now the pilot stays lit AND the main burners fire.
BUUUUT, lol
I have to click this button each time to get it to fireÂ
AAAAAND
the tubes still candle after you turn off the thermostat.Â
Does this mean I need to replace the Hi-Limit AND the combi valve?
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It sure sounds like it
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Look’s like the capillary tube on that safety high limit got damaged. They are delicate. Once kinked or damaged the control is trash. Also by disassembling it, it will no long be calibrated to the trip temp. High limits are a critical item to prevent fire with thermostat failure. or hanging
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