LPG Griddle Uneven Heat or Won’t Light: Fixes & Spares

Last updated: July 2026

In 30 seconds:

• Most “won’t light” faults are simple: an empty cylinder, a closed valve, or a tripped regulator.
• If the burner dies when you release the knob, hold it in for 30 seconds first — then suspect the thermocouple.
• Uneven heat on a Lincat GS7/P usually means one of its two heat zones is off or starved.
• Propane only, at 37 mbar supply and 25 mbar burner pressure. Never butane.
• Repairs to propane-carrying parts are a Gas Safe engineer job. Everything else here is safe to check yourself.

An LPG griddle that won’t light or heats unevenly nearly always has one of five faults. No propane at the burner, a blocked injector, a tired thermocouple, a tripped regulator, or a carbon-caked plate. This guide walks UK food-van and trailer caterers through each fix on the Lincat GS4/P (5.5 kW, from £1,104) and GS7/P (8.0 kW, from £1,499). The same checks apply to almost any propane griddle. The safe checks below cost nothing and take about ten minutes.

Read this first. You can safely check the cylinder, hose condition, ignitor and plate yourself. Repairs to propane-carrying parts — the valve, injector, thermocouple and burner — should be left to a Gas Safe registered engineer. DIY work on those parts can invalidate your warranty and your insurance.

Safe First Checks (10 Minutes, No Tools)

Run these five checks before you blame the griddle. They clear the most common faults without opening anything up.

1. Turn everything off and let it cool. Knob to OFF, cylinder valve closed, then give the plate 15 minutes. Why: you’ll be working right next to a hot plate and the burner rail.
2. Check the cylinder and valve. Is there propane in the cylinder? Is the valve fully open? If in doubt, swap to a known-full cylinder. Why: a near-empty cylinder is the single most common “fault” on a food van.
3. Check the hose and regulator. Look for kinks, cracks and perished rubber. Make sure the regulator is properly seated on the cylinder. If yours has a reset button, reset it. Our LPG hose and regulator guide covers what good looks like. Why: a tripped or failed regulator starves every burner at once.
4. Test the ignitor. Press the orange piezo ignitor and watch through the sight holes in the fascia for a spark. Wipe away grease and crumbs around the fascia first. Why: no spark means an ignitor fault, not a propane fault.
5. Relight using the full Lincat procedure. Press the knob in, turn it anti-clockwise to MAX, press the ignitor, then keep the knob held in for 30 seconds after the flame catches. Full steps are in our LPG griddle setup guide. Why: releasing the knob too early is the top cause of “it lights, then dies”.

Griddle Won’t Light at All

If the five checks above didn’t get a flame, work down this chain. It’s the same order a Lincat engineer uses.

• No spark at the ignitor. The piezo button or its lead has failed. It’s a cheap part and a quick engineer swap.
• Spark, but no flame. Propane isn’t reaching the burner. Recheck cylinder, valve and regulator — then suspect the injector.
• Blocked injector. The GS7/P uses a 0.75 mm injector and the GS4/P a 0.88 mm one. A speck of debris blocks holes that small. An engineer removes and clears it. Never poke wire into an injector — it changes the bore and ruins the flame.

Burner Goes Out When You Release the Knob

This is the thermocouple. It’s a small probe sitting 3 mm from the burner face. The flame heats its tip, the tip makes a tiny voltage, and that voltage holds the safety valve open. No heat, no voltage, no flame — the valve snaps shut. It’s a safety device doing its job.

• Hold the knob for a full 30 seconds after lighting. The thermocouple needs that long to warm up.
• Sooted tip. A dirty thermocouple reads cold. An engineer cleans it during a service.
• Weak output. Below 5 millivolts, the thermocouple can’t hold the valve open. Replacement is Lincat part TC34.
• Wrong gap. The tip should sit 3 mm from the burner face. Months of road vibration can shift it — one reason the six-month service matters on a mobile setup.

One Side Hot, One Side Cold

The Lincat GS7/P runs two burners as two independently controlled heat zones, each with its own knob. Before anything else, check the second zone is actually switched on and lit — look through the sight holes. If one burner won’t light while the other runs fine, that burner’s injector or ignitor is the likely fault.

Also check the unit is level. Lincat’s commissioning checks require it. On a sloping pitch, oil pools at one end of the plate and food cooks unevenly — level the van or trailer before you blame the griddle.

Hot and Cold Spots Across the Plate

• Carbon build-up. Baked-on carbon insulates patches of the plate. Scrape after every service, and use a wire brush (with eye protection) on stubborn deposits on steel plates. Our griddle cleaning and seasoning guide has the full routine.
• Overloading with frozen food. The 12 mm machined steel plate holds heat well, but a full load of frozen burgers pulls the temperature down wherever they sit. Work in batches — the GS7/P is rated for around 190 four-ounce burgers an hour.
• Not enough heat-up time. From cold, the plate needs a full 20 minutes to reach working temperature. Judge it after 20 minutes, not 5.
• Wind. A draught through the serving hatch cools the plate edge nearest the hatch. Shield the appliance side of the hatch on windy pitches.

Weak or Lazy Flame

• Cylinder running low. Propane pressure falls away as the cylinder empties. Shrinking flames near the end of a cylinder are normal — swap it.
• Cylinder frosting. Heavy draw on a small cylinder in cold weather chills it and drops the pressure. Move up a cylinder size, or run two cylinders with a changeover valve.
• Kinked or crushed hose. Check the full run, especially where it passes through van bodywork.
• Burner pressure out of spec. The GS range runs at 25 mbar burner pressure from a 37 mbar propane supply. Only an engineer can measure this, at the test nipple behind the fascia. Wrong pressure gives lazy or roaring flames.
• Yellow, sooty flames. That’s incomplete combustion — a soot and carbon monoxide risk. Stop using the appliance and have it checked before you trade on it again.

Quick Fault-Finder

Spares Worth Knowing

Lincat publishes part codes for the GS range, which makes ordering painless. Carrying the small ones on the van cuts downtime — though fitting anything propane-carrying stays an engineer job.

When to Call a Gas Safe Engineer

• Any work on propane-carrying parts — valve, injector, thermocouple, burner, or pressure setting.
• Every six months. Lincat recommends a service at that interval. The engineer checks burner pressure, burner condition and the 3 mm thermocouple gap, then leak-tests the appliance. Our LPG griddle maintenance guide covers what you handle between services.
• Annually for the van. Your yearly gas safety check covers the whole installation — hose, regulator, pipework and appliances together.
• Warranty. Lincat backs the GS7/P with a 2-year parts and labour warranty. Work by anyone who isn’t Gas Safe registered can invalidate it — as can misuse, incorrect adjustment or modification.
• Never clean the unit with a water jet. Warm water and detergent only on the outer panels.

If faults are stacking up on an old griddle, weigh repair costs against replacement. A new Lincat GS4/P starts from £1,104 and the twin-zone GS7/P from £1,499 — browse the full LPG griddles range to compare.

LPG Griddle Troubleshooting FAQs

Why won’t my LPG griddle light?

Usually no propane is reaching the burner: an empty cylinder, a closed valve, a tripped regulator, or a blocked injector. Check the cylinder, valve, hose and regulator first — that solves most cases in minutes. If there’s no spark from the piezo ignitor, the ignitor itself has failed and an engineer can replace it cheaply.

Why does my griddle go out when I release the control knob?

Either the knob was released too early or the thermocouple is failing. Hold the knob in for 30 seconds after the flame catches so the thermocouple heats up. If it still dies, the thermocouple is sooted, out of position, or producing under 5 millivolts — an engineer can clean, re-gap or replace it (Lincat part TC34).

Why is one side of my griddle hot and the other cold?

On a Lincat GS7/P, each side is a separate heat zone with its own burner and knob — check the second zone is switched on and lit. If one burner won’t light while the other runs fine, that burner’s injector is probably blocked. A griddle that isn’t level also pools oil and cooks unevenly.

What pressure should an LPG griddle run at?

UK commercial LPG griddles run on propane at a 37 mbar supply pressure, regulated to 25 mbar at the burner. Only a Gas Safe engineer should measure or adjust burner pressure — it’s read at a test nipple behind the fascia panel. Wrong pressure causes weak, lazy or roaring flames.

Can I run my catering griddle on butane instead?

No — use propane. Butane stops vaporising below about 2°C, so a butane-fed griddle loses power or dies exactly when UK outdoor caterers need it most. Commercial mobile catering appliances, including the Lincat GS range, are rated for propane at 37 mbar.

What spares should I carry for a Lincat GS griddle?

A spare thermocouple (TC34) is the best value — it’s the commonest wear item on both the GS4/P and GS7/P. Injectors (JE141 for the GS7/P, JE67 for the GS4/P) and a control knob (KN184) are small and cheap to hold. Fitting propane-carrying parts is an engineer job, but having them on the van cuts downtime.

How often should an LPG griddle be serviced?

Lincat recommends a service by a competent engineer every six months. The service checks burner pressure (25 mbar), burner condition and the 3 mm thermocouple gap, then leak-tests the appliance. Mobile caterers also typically need an annual gas safety check on the van’s whole installation.

Do repairs void my Lincat griddle warranty?

Unqualified repairs can. Lincat’s UK warranty — 2 years parts and labour on the GS7/P — excludes damage from misuse, incorrect adjustment, modification or unauthorised service work. Keep repairs with Gas Safe registered engineers and keep the paperwork. Routine cleaning is fine, but never use a water jet on the unit.