Good day. We have a Napoleon fireplace Model GD40-P which is approx. 12 yrs old and used very rarely. I turned it on this time to warm up the house and it worked perfectly for approx. 1/2 hour: then all the flame went out but the pilot light is still on. The fire will not "spread " to the surrounding piping in the fireplace. no amount of attempts at re-lighting seems to work even though the pilot light is still on. Do you have any idea what might be causing this? Thank you.

SOURCE: fireplace clicks and shuts off when running

There are a few things that could be causing this problem. The most common resolution to this problem is making sure the thermo couple is screwed tight into the valve. While looking at the gas control valve, you'll see a few wires and small metal tubes going into it. The one you want to tighten is the tube that is copper. Even if you get only a half a turn on the little brass fitting that's holding it screwed in, that's usually enough. If that doesn't do the trick let me know and I'll get back to you with some other things to try.

SOURCE: I installed a Napoleon Gas fireplace model BGD33NG

Make sure the pilot is turned to the ON position, otherwise you might have a broken thermopile which will need to be replaced as it controls the burner.