I only recently discovered "The Virtual Weber Bulletin Board" and have read many posts concerning mostly problems with Weber gas grills not coming up to desired temperature, and very few related to excessive temperature - my problem is the latter. This particular grill, a natural gas Weber Genesis II E/S-320, #89557, was purchased new in 2008; and other than the recent addition of new heavy duty grates, burners, gas manifold, and quick disconnect hose is strictly stock; it has not been modified in any way.
During a lengthy eight month process of trying to reduce extreme operating temperatures out of the "blast furnace" range it appears Weber could have used an incorrect orifice size in both the original and a new replacement manifold. This model grill has three 14,000 BTU burners and is designed to run on 7 W.C." Before adding a regulator to the grill my mainline system 'Static' pressure was 8.260 W.C.". All of the orifices on both manifolds measured a very nice interference fit of a #51 drill bit. Incidentally, the gas valves were also checked on both manifolds and all are of the variable adjustment type. According to the Gas Orifice Capacity Charts, even at Weber's recommended 7 W.C." each burner will be producing 16119 BTU's. With the unregulated 8.260 W.C." at the grill that pressure and #51 orifice size is no doubt producing in excess of 17,000 BTU's - no wonder I'm getting extreme temperatures. Prior to adding a regulator, even with all three burners operating on a Low setting, they were putting out over 500 degrees. With three burners on High the temperature was 725 plus and still climbing - and it's wasn't a whole lot better with two on High. I've used Weber, oven, and digital temperature indicators, they all agree. I had to stop using the digital probes because they maxed-out at around 550-650 and then went into meltdown and became useless. I no longer use the digital instrument/probes; but continue to test with combinations of the analog thermometers.
I won't get into a lengthy dissertation about where I am now with the grill; but I did try several regulators and now have settled on a Maxitrol RV48L adjustable 3-6 W.C." That was a big help, but not a complete success. The grill is now operating with an output from the regulator of 4.930 W.C." which should be getting fairly close to that 14,000 BTU figure based on a #51 orifice. In the meantime I will be doing more temperature tests. All W.C." pressure tests were done with an UEI EM201B digital manometer first "teed-in without a regulator; and then with the Maxitrol regulator installed and the testing tee at the input side of the gas manifold.
Basically, at this point my plan is to match orifices and W.C." pressures to get something less than the 14,000 BTU's.
My questions are:
1. When Weber states this Genesis model (as well as most of their other 2-3 burner grills) operates at 7 W.C." are they talking about static or dynamic pressure? My guess is that it would be static even though I have also been recording the dynamic reduced operating pressure with various gas valves turned on - burners not operating. Weber was no help with this question.
2. Weber also publishes that at Low the operating temperature range should be 250-350, Medium 350-450, and High 450-550. I checked with their Customer Service to verify that these temperatures were with all three burners operating, they answered, "Yes." I have not as yet been able to stay within these parameters with three burners. Are these temperatures consistent with what members have on your grills?
3. I think (hope) I am on the right track in temperature reduction with the selection of orifice sizing matching desired W.C." pressure, but would sincerely appreciate any words of wisdom and advice that you, the group, might have.
During a lengthy eight month process of trying to reduce extreme operating temperatures out of the "blast furnace" range it appears Weber could have used an incorrect orifice size in both the original and a new replacement manifold. This model grill has three 14,000 BTU burners and is designed to run on 7 W.C." Before adding a regulator to the grill my mainline system 'Static' pressure was 8.260 W.C.". All of the orifices on both manifolds measured a very nice interference fit of a #51 drill bit. Incidentally, the gas valves were also checked on both manifolds and all are of the variable adjustment type. According to the Gas Orifice Capacity Charts, even at Weber's recommended 7 W.C." each burner will be producing 16119 BTU's. With the unregulated 8.260 W.C." at the grill that pressure and #51 orifice size is no doubt producing in excess of 17,000 BTU's - no wonder I'm getting extreme temperatures. Prior to adding a regulator, even with all three burners operating on a Low setting, they were putting out over 500 degrees. With three burners on High the temperature was 725 plus and still climbing - and it's wasn't a whole lot better with two on High. I've used Weber, oven, and digital temperature indicators, they all agree. I had to stop using the digital probes because they maxed-out at around 550-650 and then went into meltdown and became useless. I no longer use the digital instrument/probes; but continue to test with combinations of the analog thermometers.
I won't get into a lengthy dissertation about where I am now with the grill; but I did try several regulators and now have settled on a Maxitrol RV48L adjustable 3-6 W.C." That was a big help, but not a complete success. The grill is now operating with an output from the regulator of 4.930 W.C." which should be getting fairly close to that 14,000 BTU figure based on a #51 orifice. In the meantime I will be doing more temperature tests. All W.C." pressure tests were done with an UEI EM201B digital manometer first "teed-in without a regulator; and then with the Maxitrol regulator installed and the testing tee at the input side of the gas manifold.
Basically, at this point my plan is to match orifices and W.C." pressures to get something less than the 14,000 BTU's.
My questions are:
1. When Weber states this Genesis model (as well as most of their other 2-3 burner grills) operates at 7 W.C." are they talking about static or dynamic pressure? My guess is that it would be static even though I have also been recording the dynamic reduced operating pressure with various gas valves turned on - burners not operating. Weber was no help with this question.
2. Weber also publishes that at Low the operating temperature range should be 250-350, Medium 350-450, and High 450-550. I checked with their Customer Service to verify that these temperatures were with all three burners operating, they answered, "Yes." I have not as yet been able to stay within these parameters with three burners. Are these temperatures consistent with what members have on your grills?
3. I think (hope) I am on the right track in temperature reduction with the selection of orifice sizing matching desired W.C." pressure, but would sincerely appreciate any words of wisdom and advice that you, the group, might have.
