The heater runs for approx. 7-10 minutes then shuts down

very rarely it's the circut board.most likely it will be the photo cell.does you photo cell have one blue wire and one white wire????or is it two blue wires,they are two differant photo cells.if it's two blue wires you nee to check the air pressure.it's very important.if the pressure is wrong it will not work properly.you need a gauge to check it.