We moved into a used (10 years old) house with a Heatalator gas fireplace.  It was supposed to be working, but we could not get it to hold a fire.  The fellow who passed it before closing said it held for him.  But he could not get it to work for us.  He spent 5 hours changing over everything except the valve, without success.  The pilot is small, when the flame comes on it stays for only a minute, then goes off again.  I wondered if someone threw chemicals in it to make colors, and they clogged something.  I cannot think it was working before the closing and will not work now.  Is anyone able to evaluate this problem? 

Has anyone replaced the thermocouple yet? I'd would.