Jerry’s Tech Talk: Fixing Fryers
July 8, 2009 by: Jerry Green
When your fryer goes down you probably want to get it up and running again fast. Fortunately, commercial fryers are generally easy to fix, and parts are also pretty easy to come by. There are four fryer parts that most commonly cause a fryer to fail:
1. Hi-Limit
2. Thermopile
3. Combination Safety Gas Valve
4. Thermostat
BE SURE TO TURN OFF THE POWER AND/OR GAS FIRST!
How to determine what the problem is:
1. If the pilot light will not stay lit, one of three things have failed. First, check to see if the hi-limit is the culprit by taking one wire off and connecting it with the other wire. Do as you always do and light the pilot. If the pilot remains lit, then the high limit is bad and needs to be replaced.
To replace the hi-limit, you first need to empty the oil from the tank. This needs to be done because the sensing bulb for the hi-limit enters through the side of the tank. There is a large nut in the side of the tank and a smaller nut inside the large nut, loosen and pull these off. Now you can remove the defective high limit. Reverse the procedure to install the new hi-limit. Always screw the larger nut into the tank first and then the smaller nut. Light the pilot and your unit should be working.
2. If the pilot still will not stay lit, then the thermopile is most likely 
the culprit. One end is attached to the pilot and the other is attached to the gas valve. Remove the thermopile from both places and replace. Light the pilot, and if it remains lit you are good to go. Also, remember to reconnect the hi-limit wire.
3. If the pilot still will not stay lit, then the only thing left is the combination safety gas valve. To replace the combo valve, you will need 
to have a couple of pipe wrenches. This is the most difficult part to change, due to the limited space. Remember to install the new gas valve in the same direction and replace all the connections.
4. If the pilot is lit, but the fryer still does not work, the thermostat may be faulty. Only three things can happen, either the burner will not light when turned on even though the pilot is lit, the oil will not get hot enough or when the oil reaches temperature it will not shut off. In either case the thermostat will need to be replaced.
If it is running wild (will not shut off) the oil will overheat causing the hi-limit to trip out and shut everything off. By resetting the hi-limit and relighting the pilot and it stays lit, then you will know that the thermostat is not good. To replace the thermostat follow the same instructions for replacing the hi-limit.
Check out more food service parts.
My deep fryer is a liberty 115000btu propane unit and after using it for about half an hour at 375degrees it quits.. I wonder if I need a new thermocouple? I press the red reset high limit button then turn the gas valve off and wait 2 or 3minutes relight the pilot it comes on turn it to gas on the knob and then I turn the thermostat to 350 or so and nothing happens… Could the high limit be faulty ??? Do I have to wait longer? Will the fryer work without the high limit control??
Hi Don,
I talked it over with Jerry and we’re pretty sure your thermostat and your high limit are shot. Read the post above for some instructions on testing your high limit.
More importantly, though: how old is this fryer? I know quite a few people who have been in the food service equipment business for a long time and only one of them had ever even heard of a Liberty fryer. It might be time to upgrade: click here to take a look at some new fryers.
As far as finding replacement parts for your Liberty, I’m not really sure what to tell you. You can try calling 1-888-388-6372 (Tundra Specialties: they don’t stock Liberty parts but they MIGHT be able to special order them).
Good luck.
I have an Imperial ifs50 recently replaced hi limit now 3 weeks later the pilot stays lit and the burners just slightly f licker ( like just a little gas is coming trouugh) I have a replacement thermostat i temporary wired it in and it still wont light the burners. Possibly the Valve???
Hi Erik,
Your problem is most likely your combination safety valve. Also make sure you check your burner orifices as well for any obstructions. Click the link at the top of this post to order a new combo safety valve with same day shipping.
Hi,
I have a American Range fryer Model # AF45 , the problem I’m having is when I go to turn the thermostate on the pilot light goes out every time. I relight the pilot light and go to restart by turning the knob and it goes out. Can you help me in determining what needs to be replaced. Thanks!
Hi Strac,
You need to go through a process of elimination to determine why the pilot light will not stay lit. You need to test the hi limit, the thermopile, and the combination safety valve to find the culprit. Follow the instructions in the post above starting with “1. If the pilot will not stay lit:”
Hi Greg,
After testing the Hi limit and finding that it was fine I changed the thermopile and the fryer workes just fine. Thanks for the help. I do have another question for you, Is there a way to test the thermopile to see if it is working without buying a new one. I think I saw some kind of device somewhere to do that. Thanks again for your help!
Regards,
Strac
Hi Strac,
I talked it over with Jerry and it is technically possible to test the thermopile without changing it out, but you would need a first-rate voltage meter that went down to millivolts. That’s because the thermopile only registers about 750 millivolts of power when it’s working. That requires a pretty sensitive instrument that’s going to cost you some money.
Unless you already have a voltage meter that is that sensitive, it’s going to be much cheaper to change out the thermopile and see if that fixes your problem.
Let me know if you have any other questions. Thanks!
My deep fryer has several holes in the stainless steel tub, whats the best way to repair this? can “JB weld” be used?
Hi Manny,
I talked it over with Jerry and I’m sorry to say you’re going to need to replace your fryer. Those holes are a result of stress fractures in the stainless steel that form over years of superheating and cooling. No matter how much you try to patch those holes, more are going to form as metal fatigue gets worse and worse.
Sorry to be the bearer of bad news… But you can check out new fryers here: commercial fryers.
Hello
We have a Pitco Frialator at work. For some reason, in the afternoon around 1 or 2pm the fryer would go crazy bubbling and boiling violently, like there was air coming from the bottom of the fryer. It did NOT have the sound like there was water in it. The fryer has been on all morning and only this happens in the afternoon. We could never figure out what is wrong with it. Please advise.
Thank you so much!
Gerald
Hi Gerald,
It sounds like you have two problems: firstly, your thermostat is “running wild” and needs to be replaced. Secondly, your hi limit is also shot and needs to be replaced as well. Running a fryer without the hi limit is extremely dangerous! Oil in the fryer should never, ever boil, and if it is, then you’re running the risk of a serious fire.
Please don’t use the fryer until you’ve replaced these two parts! The information on how to replace these two parts is in the post above.
I was reading Gerald’s problem. I have 4 pitco units operating and my fry shop. We had the same problems with our systems. We use real potatoes and the starch and small bits would sit in a hot frier for about 4 to 5 hours without a sound. All of a sudden these small bits would surface suddenly and all at once. Makes a horrible sound and is very scary. Our friers are working properly and the temperatures remain proper. We fixed this by (using a long teflon brush) brushing the bottom of the friers 2 hours after opening and skim the remenants off. We filter our friers at 2-3 pm every day. I hope this may help.
I have a two year old American Range that has been used a total of 6mos. and now has a small tank leak. It is no longer under manftr. waranty. Manf. was willing to give me a deal on new tank but with shipping and labor I’m still looking at $600. Can the leak be succesfully fixed another way? Or a new fryer.
Hi Ian,
Unfortunately, there is no easy way to fix a tank leak on a fryer. I’m surprised it developed a leak so quickly, but in general, when a leak develops it is because of metal fatigue from constant heating and cooling and patching won’t change the fact that the metal is worn. I would suggest purchasing a new fryer here.
I saw your blog bookmarked on Furl. I love your site and articles. Keep up the great work.
I have a Pitco unit, no idea how old. The pilot won’t stay lit. Everytime the fryer goes out we have to hit the reset switch and then go through the process of lighting it again. We set it to 350 and in about 10 minutes or less the whole thing goes out. The Pilot flame looks alittle low on one side (not sure if its always been like that). Also a year ago or so we replaced the thermopile although we really didn’t need to, we just didn’t know about the reset button. Any help would be great. Thanks
Hi You metioned of never hearing of A Liberty fryer I have two of them ”
Liberty35 Basic” 100,000 btu
they are both workink fine one is A year old and the other new the only thing I find worng is they both make A popping sound sort of like a back fire from an older car could you tell me what would cause this
thanks Don L
It’s hard to say what’s causing that sound Don. My guess is frozen food bits or ice crystals dropping into the hot oil, but I can’t say for sure. Sorry I can’t be more help!
HELLO I HAVE A PICTO EF3 DEEP FRYER, THE PILOT STAYS LIT BUT WHEN I ADJUST THE THERMOSTAT NOTHING HAPPENS, IM GUESSING THE HIGH LIMIT IS FINE BECAUSE THE PILOT STAYS LIT, I TRIED TO JUMP PAST THE THERMOSTAT AND SEE IF IT WOULD LIGHT BUT THAT DIDNT WORK EITHER. IM NOT SURE IF THAT IS POSIBLE ANYWAY I THINK IT IS BUT NOT SURE. AT FIRST THE FRYER WOULD TAKE FOREVER TO GET GOING BUT NOW WONT DO ANYTHING. AND IM TORN BETWEEN THE THERMOSTAT THERMOPILE AND GAS VALVE IS THERE ANY MORE TESTS I CAN DO TO FIGURE OUT WHICH ONE IS BAD? THANKS
Hi Robby,
The best thing for you to do would be to start with replacing the thermostat. However, the safety valve may also be bad. If you replace the thermostat and that doesn’t do the trick, you’ll have to replace that.
Hi,
I’ve an American Range deep fryer. When I turn it to pilot mode, it just give out a weak flame at the thermopile. I try to adjust the pilot flame at the adjustment knob. it just still be very small flame. The flame is so small that it could not ignite the thermopile. Please help!
Thanks
Hi I have many anet fryers and when I try to start one it makes a big bang and won’t lite what should I do?
we have three Pitco,s two 18,s and 1 14 all three carbon up bad blowing carbon out of the chimny, also fire comes back to the front of each unit and the metal on the front gets real hot, we clean the burners and tubes once a month and make sure there is know blockage.
Hi,
Having trouble with a Pitco Fryer. The pilot stays lit and fryer works fine most of the time, but recently it appears to cut off for no apparent reason. You can hear the flames go out as if they are being blown out. There is not a draft that would cause this. Any suggestions? This may happen once a week or sometimes 3-4 times a night.
Hi , recently read your post which helped me to determine my hi-limit is faulty really appreciate the info and how to test ! But im having a hard time believing theres no way to patch a leaky fryer , have an imperial ifs-40 and have a few small leaks around the cast iron heating tubes that go thru the tank , the leaks are at the front on the top of the tube where it meets the stainless tank ( not sure if the tubes are crimped and or welded/brazed to the tank ), i’m almost sure it is from the cast iron rusting from years of cleaning being exposed to water and air. Its been operating for atleast a few years with these leaks which are about 2 fl ounces in a 24hr period. I dont see the reason to purchase a new fryer at this rate , is there anyway to stop the leak ?
Hi Adam,
Glad we could help! On the leaking problem, it sounds like the stainless steel portion of the tank is slowly cracking due to metal fatigue (from constant heating and cooling). The problem with fryer tanks once they begin to leak is that the extreme temperatures involved make it almost impossible to patch a hole once it starts. This is because the metal expands and contracts so much.
That leaking oil is a fire hazard and it sounds like it’s about time to replace your fryer. Sorry for the bad news!