Two questions....

[crozzy]

Just two questions here fella's. I always like other opinions.

1.Gas valve making terrible noise, but still works.

4 1/2 Inc W.C Outlet. What causes such a noise? Slugging of the Gas valve? Or was it not purged corectly?

2. Flame roll out. On older standing pilots even newer ones, what the main over cause of flame roll out, out of the burners. Crack in heat exhanger? Dirty Heat exchanger? Crossover not possitioned right? Dirt and sediment mixing with oxegen and fuel causing a back draft?

any coments would be appeciated. Thank you.

[dave335]

it could be any one of the above.

[coolwhip]

4.5 WC is to high for natural gas and many things can cause a roll out such as sooted flue passages, misaligned burners, bad crack in the heat exchanger.

[mrssb]

I agree it could be any one of the above, but usually when a furnace is rolling out like that it is searching for oxygen to burn. I have had baffles get plugged at the top of the exchanger causing the very thing you are descibing. It is a really simple check, take the collector box off and have a look.
Also 4.5 inches of water column is way too high as stated bt others, and can cause a myriad of problems.(yes i know myriad is one of those words many will have to go to the dictionary to look up....just kidding)