Hi. Welcome to Just Answer.
I may be able to assist you. What is the make and model number of the unit and what is the problem, please.
Okay. Something is blocking the gas or partially diverting it from the correct path to the burners.
It has been my experience in cases like this that an insect has crawled into one of the gas tubes and made its cucoon.
The best way to fix the problem is to remove the gas tubes and blow them out real good with an air compressor.
If blowing out the tubes doesnt work then the burner controls are the next thing to blow out good.
What convinces me that this is the problem is the half on half off burners. This is a typical indicator of an obstruction blocking or partially blocking, one half of the supply tube.
Please let me know if you have any other questions.
No not really.
The gas flows from the tank to the regulator and then to the burner controls. Up untill this point the gas is in a sealed system.
Once the gas gets to the burner controls it is injected into the tubes that carry it to the burners by "spuds", or gas jets.
The gas is then mixed with oxygen (air) by blowing past the air fuel mixture shutters. From there is flows to the burners and is burned.
If ANYTHING interrupts the flow it can cause all kinds of strange burning problems. From popping, to flames an inch and a half off the burner that sounsa like a freight train, and even flames that appear normal...... for a munchkin.
The flow of gas must be uninterrupted to burn correctly. If the gas is not burning correctly then the first thing to check is the flow.
Blow out everything from the burner controls to the burners. That will get you going again.
It wont hurt to blow them out. The manifold that they connect to is the more likely problem area.