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Undersized feed to stove?
I have recently installed a new natural gas range. Its being fed by the same 1/2" pipe as my old stove. Only thing really different than my old stove is that has that center burner and an extra "power burner".
I noticed after I installed it, the manufacture suggest a 3/4" pipe for the supply and that "smaller pipe may result in insufficient gas supply". It appears to work correctly though, there is solid blue flame on all the burners, no yellow whatsoever and I dont see any dimished flame height as I put on all the burners even with my furnace and water heater running at the same time.
However, if I calculate the BTU requirements for the stove and compare it to the gas sizing chart using the longest run method I am falling short on the 1/2" btu (providing I calculated correctly).
This happens when I calculate all the burners, broiler and oven btus from the nameplate on the appliance. However, if cheat a bit I can make the numbers work... for example, the combined BTU's include both the oven and broiler (both of which cannot be turned on at the same time). So that drops my btu requirement further. Their is a center burner as well that is never used in conjunction with the stove and other burners... that drops me further. That drops my btu requirment right at the maximum allowed on the chart.
I still thought I should have a plumber look at it and I had a guy out for an estimate to repipe that section and he said he had never installed a 3/4" pipe feeding a standard range in a residence like I have. That it would be overkill and that he wouldnt go to the trouble and expense if everything is working properly as its very rare you would use the entire btu ratings on the nameplate of the stove. However, since the manufacture suggests a 3/4" pipe he can change it if I like. It would cost more than the stove itself to do this.
FWIW: Here is what I calculated:
Stove is farthest appliance from meter. Its 78K btu counting everything on the nameplate. The stovetop is 51K alone. My meter is 250K with a regulator rated at 5"-7" wc. Its more than I need for my gas usage which also includes a furnace (70K) and WH (40K). The main trunk from the meter is 1". Also more than I need for my service.... 3/4 would suffice.
The stove is located 60' from the meter.... 1" trunk runs about 54' and then there is a 1/2" branch to the stove for 6'. It is that 6' that is undersized. I added 50 percent for fittings which I think is the correct formula so a total run of 90'? I think if the 50 percent extra for the fitting factor is not added then their is not much of an issue at all.
Should I open a can of worms to replace that 6' section of 1/2" pipe?