Hi, I'd like to bump this thread up and pass on my "conversion" story. I'm not suggesting anyone to jump in and do it as there are dangers as mentioned by many. I wanted a "Weber " but am on a limited budget . I know Weber quality and endurance and I'm tired of replacing grills every 2-3 years. After long searching I found an S-310 NG grill for a little more than 300 dollars and about three years old. Pictures showed it was taken care of quite well. I made the plunge KNOWING I had to convert the fuel supply to LPG . There are lots of postings about conversions, all with the same message,,,it's dangerous ,should be done by experts and it's not cheap. Conversion normally involves exchanging the entire manifold assembly (with control valves and orfices) so to be compatable with the LPG. Other changes are needed such as regulators ,fittings and hoses.
One internet site I visited showed how to make a Pressure Guage Assembly for determining W.C. pressure ,that was a great guide. It also had suggested a new regulator by catalog number to use.
I followed the advise but had issues ,,, I kept the 10 foot NG hose , kept the quick disconnect fittings and used my new regulator. I fired up the grill and found the flame was Yellow no blue color and very high even at a low control setting. I determined that the orfice holes were too large in diameter. To tacle this problem I exchanged the orfices from my old grill (not a Weber) and installed them into the S-310. Both grills are 36,000 btu grills. Job done, beautyful blue flame with tiny yellow tips ,good regulation , and a great feeling of accomplishment. I would pass on ,,work smart and use caution. If you do a conversion on any grill change the identification label so future owners/users know the grill has been converted.
Happy grillin
CLIFF