Check for debris around the patio heater burner pilot and clean out insects and ensure the area is clean and dry.
There may be low fuel pressure, ensure the gas cylinder has sufficient fuel and is turned ON at the regulator. Ensure the regulator is not worn and working OK. Avoid using butane (in UK blue LPG gas cylinder) during the winter months, patio heaters will operate more effectively using propane during cold periods.
If the cylinder is full, check for leaks - see item 7 below for details on how to conduct a leakage test.
If points 1 to 3 are OK the probable cause will be failure of the patio heater thermocouple. If the pilot on the patio heater lights up and then goes out when the gas control knob is turned on full then this is most likely a worn thermocouple. Thermocouples are consumable items and need replacing. Most last 2 to 5 years but this is dependant on usage and the type fitted. To replace the thermocouple refer to the spare parts page and thermocouple AFX480 for Heateray Pro and thermocouple AFX485 fitted to BFX branded domestic patio heaters. New thermocouple should be fitted according to the manufacturer's instructions, read thermocouple function page before ordering spare parts.
Check the LPG gas cylinder is turned ON and contains fuel. Ensure the regulator fitted is working and the correct type for the cylinder. A butane cylinder will struggle to work during the winter, always use propane if the weather is below 6 degrees.
Allow 30 seconds for the LPG gas to reach the chamber before trying to light the burner. The latest European patio heaters are factory fitted with pulse pilots that give a lower pilot flame. EU regulations changed in 2009, if you have the latest type it can be difficult to smell or hear gas due to improved gas valve technology. If the patio heater is a newer type and not lighting quickly try venting before making a repair. To vent, turn the gas cylinder ON, turn the gas knob to pilot and hold for 90 seconds. Turn knob to full but don't light and turn to OFF. Next turn back to pilot, click on ignitor, hold for a further 30 seconds, slowly release and try not to shake the pole. For budget market patio heaters this is a common problem, contact seller for a replacement burner.
The burner may have a blockage preventing the fuel reaching the chamber. Remove the LPG hose and check for insect/debris blockage, if a blower is available try blowing through the LPG hose. Next, remove the flame emitter screen by removing the screws holding the flame screen in place. Lift the flame screen off the burner to access the piezo igniter spark and thermocouple. Check the area for any signs of carbon build-up and clean. Look for any debris, insects and water within the area and remove/clean.
Test the piezo is sparking, turn the gas OFF and push the piezo ignitor, you should see a spark. To test the piezo igniter is working OK remove the ignition lead at rear of the igniter, place your thumb over the end and press the red button - you should feel a small sting. The piezo igniter should be close to the thermocouple, if it has dislodged so the spark cannot reach adjust it until a spark can be seen. If the piezo igniter is failing to produce a spark check the igniter lead is connected to the rear of piezo igniter. A new piezo igniter, see piezo igniter AFX470 for Heateray Pro, piezo igniter AFX475 for domestic patio heaters and piezo igniter AFX477 for electronic commercial patio heaters, should be fitted according to the manufacturer's instructions.
Check the tilt switch (if fitted) function. A failed tilt switch will prevent the LPG gas entering the gas control valve. Older patio heaters will have a factory fitted mercury tilt switch, newer models are fitted with mechanical tilt switch type A these are very simple to replace.
If there are no blockages and the thermocouple is working OK remove the electromagnetic valve (located at the rear of the gas control valve and if worn or appears damaged replace with a new electromagnetic valve. These can fail due to frost and weather but often there is no visible sign of wear, the only real test is to exchange for new.
Loose connections need to be checked by using the procedure for a leakage test. Patio heaters can be leak tested by making a soapy solution of one part liquid detergent (washing-up liquid) and one part water. The soapy solution is applied using a clean spray bottle or clean paint brush. Turn the LPG gas supply on but DO NOT light the burner. Make sure the safety control valve on the burner is in the OFF position. If a leak is present, turn OFF the LPG gas supply at the cylinder. Tighten any fittings, use plumbers tape to seal and re-test. Continue checking until all leaks and connections are tighten according the patio heater's manufacturer's instructions.