Check to see if the supply tank valve is open and regulator is set at the medium setting and you are manually holding the safety shutoff open. If all this is ok and you still don't smell or hear gas then replace regulator.

Disconnect Tip switch wires and connect the wires together with a paper clip or jumper wire. If the heater works, change the Tip Switch, If not, change the Thermocouple.

Clean unit per instructions. Check for spiders and dust in back plenum tube. The screen may also have a burned out section and need to be replaced.

Puff of wind, or dirt or spider in riser on back just above safety control valve, called BACK FLASH. Solution: Block from direct wind flow. Clean out riser tube with pipe cleaner and low pressure air or screen defective. If the above doesn't work, replace burner assembly.

This will go away once heater has warmed up.

When the heaters leave the factor they have a glue that helps the connection on the Tip-Over switch stay firm but that can still come loose. Take pliers and squeeze the connections tight. Try starting the heater again. If the problem still occurs then contact Technical Support and we will help with final troubleshooting.