Have a Trane XL80 furnace. We switch the furnace on but after the initial ignition it turns off. And then repeats about a minute later, and then again. Only one and sometimes three of the burners are temporarily igniting. We have removed and cleaned the heat sensor and replaced the igniter switch and still same problem. Please can someone help?

Have a Trane XL80 furnace. We switch the furnace on but after the initial ignition it turns off. And then repeats about a minute later, and then again. Only one and sometimes three of the burners are temporarily igniting. We have removed and cleaned the heat sensor and replaced the igniter switch and still same problem. Please can someone help?

Please can someone help?

The best help I can give you is to call a qualified ON SITE contractor before you blow the furnace up. When the burners are not lighting in unison that means that RAW unburnt gas is being injected into the furnace. This is NOT a good thing at all. Please call for ON SITE qualified help before you hurt yourself.