New house- Gas log fireplace

Just moved into this house and it has gas log fireplace. Never had any kind of fireplace before.
I am having trouble with this unit. So far have not been able to find any label to indicate the brand or model number. I can only tell you that it is a totally manual set-up. No electricity anywhere near the unit.
We are able to light the pilot and the flame is robust and envelops the tip of the thermocouple. The pilot stays lit after holding the gas valve button in for a short time. Up to this point everything everything sound good?

This is where the problem arises. After a bit I try to turn the unit on. I twist the knob and it hits a stop and won't turn on. I wait 10 minutes and the same, will not turn.
So I guess my question. On this type of unit does the thermocouple do double duty? Control both the pilot and burner?
After about a half hour or more the unit will allow me to turn the knob and the burners light.

 

Welcome to the forums.

It's really hard to guess at what you have. More than likely your fireplace has a thermocouple and a thermopile. The thermocouple keeps the gas valve open and the thermopile powers the main burner valve. Some unit just have a thermopile. The pilot flame should be fairly large.

See if you get a few pictures of what's there and post them for me.... How-to-insert-pictures

 

I have a similar problem with my gas logs at the beginning of the season. Usually after it eventually lights it gets better and better as cycles on and off several times. It seems the gas valve is a bit sticky from sitting 9 months without use but after it's been cycled several times it works fine.

You can try cleaning the bulb of your thermocouple/pile. A deposit of soot or dust could insulate it just enough to prevent it from working. You should also look at your pilot flame to insure it is the proper size and is properly aimed.

If yours doesn't get better with a few cycles and cleaning then you might need to replace the thermopile. They seem to get weaker with age and eventually don't produce enough electricity to activate the gas valve. If you order the correct part it's a pretty simple job to install the new one.

 

Thank you. Will post some pics as soon as I find my camera. Just moved and we're still emptying boxes.

 

Eureka. It is working. A case of operator error.
Found problem by pure dumb luck. When I try to start it I have to let the knob out a bit and it will let me turn it.
Thank you for responding to my post.