Hi, when I checked the line on the boiler side of the filter there was nothing. I then thought to check the filter but when I unscrewed the two screws on the cap I assumed the lower part would pull off but it wouldnt. I therefore decided to leave it. Tomorrow I thought I would check the line into the filter to see if there is any flow there, and then work my way back to the tank. Is it possible for the kerosene to freeze up in these temps as I know that my oil suplly line from the tank runs about 2 or 3m aboveis ground and not insulated at all?