Food Trucks · Fryer Not Heating · LP & Electric
Food Truck Fryer Not Heating
Fryer cold, slow to recover, or shutting off mid-service? We check the high-limit, pilot, thermopile and LP pressure on gas fryers, and the power on electric ones. $120 diagnostic, waived with repair.
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Our Branches
10 service territories across Southern California
01 · Gas fryers
Gas fryers on a truck: what we check, in order.
A fryer that won't heat stops a truck menu faster than almost anything else. Our techs work through it the same way every time, from the cheapest explanation to the most expensive, because the cheap ones are common on trucks. This is one of the calls we cover under food truck equipment repair.
- The high-limit tripped. The high-limit is a safety cutoff that kills the burner if the oil overheats. It trips for a reason: oil run low, a thermostat stuck calling for heat, or a vat fired after draining. Trucks add one more: parked on a crowned street, the vat isn't level and oil runs to one end. Reset it once. If it trips again, shut it down and call.
- The pilot is out. The service window pulls a draft across the fryer, grease clogs the pilot orifice, and vibration loosens the pilot tubing so the flame drifts off the thermopile.
- The thermopile is tired. Most basic open-pot gas fryers use a millivolt system. The pilot heats a thermopile, and the thermopile powers the gas valve with no outside electricity at all. We read its output with the burner calling for heat and compare it to the manufacturer's spec. A thermopile sagging below spec gets replaced, not cleaned. Before that, we check its leads at the gas valve terminals: vibration loosens them, and a loose terminal looks exactly like a dead thermopile.
- The thermostat or gas valve. With a good pilot, a good thermopile and a closed high-limit, a burner that still won't fire points to the thermostat or the valve itself.
- The LP supply can't keep up. A griddle, a fryer and a char-broiler pulling from small cylinders at once can outrun how fast propane vaporizes. Pressure drops, flames shrink, and the fryer takes forever to recover after a basket goes in. Frost on the outside of the cylinder during a rush is the visible clue. We confirm it with a manometer at the fryer inlet with everything running. The fix is cylinder size or setup, which belongs to your propane contractor.
- A natural gas fryer that was never converted. Same story as griddles: different orifices, different pressure. The fix is the manufacturer's LP conversion kit. We don't drill orifices.
If the griddle next to it is also struggling to light, the cause is often upstream of both; see food truck griddle won't light.
02 · Electric fryers
Electric fryers on generator power.
An electric fryer is usually the biggest single load on a truck generator. Its elements are fixed resistances, so heat output drops faster than voltage does. A sag that barely dims the lights can take a real bite out of fryer recovery. That's why the same fryer can feel fine on commissary power and weak at an event.
We measure voltage at the receptacle while the fryer is firing and other equipment is running. Then we test each element's resistance, the contactor that switches them, the thermostat and the high-limit. A burned element or a contactor with pitted contacts is ours to fix. A generator that can't carry the load is a generator shop's, and we'll hand you the readings to take with you.
Whatever we fixed, gas or electric, the fryer doesn't go back into service on our word alone. We bring the oil up to your frying temperature, watch the burner or elements cycle at setpoint, then drop a load in and time the recovery. On gas fryers we confirm the pilot holds with the service window open, because that's how the truck runs at lunch, and every gas fitting we loosened gets leak-tested. On electric fryers we read the current on each element, so one weak element can't hide behind the two that still work.
03 · Before you call
What you can safely do before we arrive.
Never bypass or jumper a high-limit, and never fire a fryer with oil below the fill line. If you smell gas, close the cylinder valve, don't light anything, get everyone out of the truck, and call your propane supplier or 911 from a safe distance.
- Check the oil level against the fill line.
- Reset the high-limit once, at the location the manufacturer shows. If it trips again, stop.
- Relight the pilot following the instructions on the fryer, with the service window closed.
- On an electric fryer, check the breaker and whether something new got added to the generator.
- Leave the panels on and the gas valve alone. Everything past that is our job.
04 · Pricing
What it costs.
The diagnostic is $120, and it's waived when you approve the repair. On our commercial fryer work, a thermopile replacement typically runs $260 to $440, a high-limit switch $260 to $380, a gas valve $480 to $720, and an electric heating element $480 to $820 depending on the model. When the answer is a loose terminal or a reset with a real cause found, you pay the diagnostic and nothing more. Repairs carry our 90-day labor warranty.
06 · FAQ
Food truck fryer questions.
My fryer's high-limit keeps tripping. Can I just keep resetting it?
No. Reset it once. The high-limit is the safety cutoff that stops the burner when oil overheats, and it trips for a reason: low oil, a thermostat stuck calling for heat, or a vat fired without enough oil. If it trips again, shut the fryer down and call. Resetting a high-limit over and over, or jumpering it, is how fryer fires start.
The pilot stays lit but the main burner won't come on. Why?
On a millivolt fryer, the pilot heats a thermopile that powers the gas valve. A lit pilot with a dead burner usually means the thermopile isn't making enough output, its leads have vibrated loose at the gas valve terminals, the high-limit is open, or the thermostat or valve has failed. We check them in that order with a meter, because a loose terminal costs nothing to fix.
Why is there frost on the propane cylinder when the fryer is slow?
Frost means the cylinder is being drawn hard and propane can't vaporize fast enough to keep up. Pressure drops, every burner on the truck weakens, and the fryer recovers slowly. We confirm it with a manometer at the fryer inlet with everything running. The fix is on the supply side, like cylinder size or setup, which is work for your propane contractor.
My electric fryer is slow on the generator but fine at the commissary. Is it the fryer?
Often it's the voltage. An element's heat output falls faster than the voltage does, so a modest sag on a loaded generator makes a noticeably weaker fryer. We measure voltage at the receptacle while the fryer is firing, then test the elements and contactor. A burned element or pitted contactor is ours to fix; a generator that can't carry the load is a generator shop's.
What does it cost, and how soon can you come?
The diagnostic is $120 and it's waived when you approve the repair. Same-day service is available across Los Angeles, usually at your commissary, with phones answered 24/7. You get a written quote before any parts are ordered.
07 · Related
More food truck service.
Fryer cold before the rush? Call now.
$120 diagnostic, waived with repair. Mon–Sat 8am–8pm · Sun closed · Phone answered 24/7.