@FiremanT have you seen this thread?
Only just seen it as my NY resolution was to stop wasting so much time in here and facebook.
I suspect strongly that the manufacturer engineer is wrong
. If the burner was cracked, there would be a constant gas smell, if you think about it. It also has nothing to do with the thermocouple - that is doing it's job. And the famous split heat exchangers will not cause this issue,
I have read the earlier posts and a few have got what I thought of straight away. Including Bernie, then he went off an a tangent that I could not be bothered to pursue or translate. I think Gas Guru mentioned cross lighting. These fires have always been able to be run in between settings. The initial light up is on the centre radiant(s), unless the initial light up is too ALL of the radiants, and then the control knob regulates the gas to them all at once. I am guessing this fire is the former. (remember I have been out of fires for years) Each turn to to the DESIGNATED position then brings on the further settings. Where the increase in setting involves bringing on another radiant, the ignition of tthe nect radiant will take place by the use of very small holes in the burner to "cross light". On an older dirty fire, these holes get blocked and cross lighting does not occur, resulting in explosive ignition, and/or a smell as encountered here. The burner will always pass a low volume of gas if the knob is turned on just enough. There will not be enough gas to cross light, and will escape into the room. As someone said, gas stinks and a tiny amount will be noticeable. The passing of gas in that rgard is normal, as far as the valve is concerned.
So, if the Dad was able to use an identical fire succesfully, then the fault probably lies within the gas valve - the notches are not defined enough, thus making it difficult to land on the correct position. This may not be unique to his fire, it may just be a result of generally less well engineered new products. Either that or the cross lighting ports are not big enough, or have been restricted with fluff. If you look carefully with the fire on high you will see these ports burning. If any one TRIES to run the fire with a burner very low, they will be able to, and defective CLP's will cause a smell.
It will be interesting to see if a new fire makes a difference.