Single stage or dual stage propane regulator? He is our experience!  

Dude, you should educate yourself at least a little before you try to give advice to others on a subject.

An outside LP tank in below zero temperatures with low amounts of LP in the tank can loose pressure, sometimes quite drastically and then rebound to normal pressure after the furnace has quit burning or the sun comes out and warms the tank up. A tank that is insulated with snow can make this problem even worse. The regulators outside can also be affected by moisture and frost that will make them not act correctly.