Gas Fireplace - Small Tank - Fire goes from roaring to wimpy

I have a gas fireplace. I have not purchased a large tank. I hooked a small grill size tank to my gas line. The fire lights and burns 5 sec good, then goes to a tiny flame. Tried adjust flame knob and everything.

Is this too small of a tank?

Does pressure has something to do with it?

I have appox. 50 feet of line also. Line comes in house, goes up to attic, goes over, comes down to fireplace.

Im just wondering if Im screwing something up before I go and buy a large tank and the problem is not the tank at all.

Please help. Many thanks in advance.

How many BTUs is your fireplace? What size is your gas line?

Matt

If it's one of those 5 gallon tanks about the size of a rolled sleeping bag and your unit is less than 90,000 BTU's then your tank is plenty big enough. If you are using a tank the size of a 2-liter bottle then your tank is too small. Sounds more like your regulator can't keep up, or your gas line is too small.

If you ran the appliance fine with the same gas line and length with the original bigger tank, then I'd say the regulator you have is underrated. What happens in that case is the line pressure is about 12 inches of water, then your appliance turns on and quickly depletes the pressure in the line and the regulator can't keep up - so the flames drop.

I had a problem like this with a propane conversion on a generator once. The problem is that the cheap regulators on gas grills are limited to about 50 KBTUs or so. I found that most of the restriction is in the POL fitting that screws into the tank. Many of them are only 1/8 inch or so in diameter. I took the fitting off the regulator and drilled it out to a 1/4 inch and it improved things a lot. Just be sure you don't get any metal shavings in the regulator and give it a shot.

Chris