Okay, I'm new to the forum and I hope someone can offer me some help in diagnosing my problem which is, I have a 5hp, 40gal Magnum electric air compressor. It takes forever to pump up. It is a twin cylinder pump and only one cylinder appears to be pulling in air, if I put my finger over the air filter intake it is sucking air. If I do the same over the other air filter intake, it is blowing warm air. All lines are unobstructed. I have removed both heads and can find no visible difference between the two heads as to why one is pumping and one is not. Shouldn't both cylinders be pulling in air and shouldn't this set up pump up fairly fast? My son is fairly well versed in mechanics and he is stumped also. Any one have any suggestions or possible solutions?