We have a '99 Swift Verona with the Carver2000 fanmaster, it has the piezo ignition. I turn the knob, push down and the pilot light comes on. Then I wait 20 seconds and turn the knob for the heater to ignite but nothing happens and the pilot light goes out. Local caravan mechanic said to blow everything out with compressed air, which I've done but no result. Does anyone have some more ideas on what to check?