OP say its 30 40 degrees outside
Although he does not mention humidity level. Is it icing up? no big deal.
What 95% of the people that use HIGH pressure propane burners for a living do is turn off the gas all the way wait a few minutes relight. Sometimes in fact lots of times they pour water over tank to melt ice. Even if they dont see ice.
Its getting colder outside these are high pressure units that use fuel Like its going out of style. AND freeze up
Not like low pressure BBQs, furnaces, hot water tanks, fork lifts, fireplaces On&on that are very thrifty. Rarely freeze.