The Frigidaire FGGC3645QS and the FGGC3047QS are both Gallery gas cooktops with five sealed burners and continuous cast-iron grates; the real difference is width. The FGGC3645QS is 36 inches wide with an 18,000 BTU Quick Boil burner and a separate 5,000 BTU simmer burner, while the FGGC3047QS is 30 inches wide with a center burner that runs from 750 BTU up to 18,000 BTU. Pick the 36-inch model for more room between burners, and the 30-inch model when your countertop opening is the standard size.
What is the difference between the FGGC3645QS and the FGGC3047QS?
Both are listed on our site as current Gallery gas cooktops, and both use sealed burners, so they are close in everything except size and burner layout. According to the model pages, the FGGC3645QS pairs an 18,000 BTU Quick Boil burner with a 5,000 BTU simmer burner and Express-Select controls. The FGGC3047QS centers on one versatile burner that ranges from a 750 BTU simmer up to 18,000 BTU, with angled front control knobs. Neither page lists a different fuel type or a different burner count, so the choice comes down to the width of your cooktop opening and how you like your burners arranged.
What they share is just as useful to know. Sealed burners keep spills on the surface instead of letting them run into the burner box, and continuous cast-iron grates let you slide a pot from one burner to the next without lifting it. Both therefore clean the same way: wipe up boil-overs once the cooktop has cooled, lift the caps and grates regularly and dry everything before you relight a burner.
Is the 36-inch cooktop worth it over the 30-inch one?
Both pages list five burners, so the extra six inches most likely give them more room, which would matter when you cook with two or three large pots at once; our pages do not give burner spacing, so judge the layout in the store. If you cook for a large household or host often, the 36-inch model is easier to live with. If you cook for one or two people, the 30-inch model has every burner you are likely to use at once. Do not decide on width alone, however: the cutout in your counter decides which one fits. Our Frigidaire cooktop buying guide says to measure your counter opening before you fall for a model, because a 36-inch top needs a wider cutout.
How do the burners compare in daily cooking?
Both cooktops reach 18,000 BTU on one burner, so boiling a large pot of water is equally quick on either. The difference is at the low end. The FGGC3645QS has a dedicated 5,000 BTU simmer burner, and the FGGC3047QS lists a center burner that goes down to 750 BTU. For long simmers, such as sauces or melting chocolate, the lower number on the 30-inch center burner is listed as a simmer rating, while the 36-inch model leaves the 18,000 BTU burner for boiling and uses the separate burner for gentle heat. We do not list heat output for the other burners on either page, so if that matters to you, check the full specification at the store.
Do both models need the same gas and power connections?
Both are gas cooktops, so they need a gas supply with an accessible shutoff valve, and the igniters need a standard 120-volt outlet to spark. The FGGC3645QS page says it ships with an LP conversion kit; the FGGC3047QS page does not mention one, so ask before you buy if you run on propane. The conversion and the gas connection are work for a licensed professional. The cutout is model specific: each cooktop ships with its own template, and two tops of the same nominal width can want cutouts an inch apart, so use the template for your exact model and never cut to the old appliance’s opening. Our Frigidaire cooktop installation guide explains the cutout and clearance rules.
Will either cooktop show error codes?
No. Our model pages for both say that gas cooktops are diagnosed by behavior, not by code. A burner that clicks and does not light, or a burner that will not click, is a symptom you read with your eyes and ears. The L indicator on a display is the control lock and not a fault. If a burner fails to light, our Frigidaire range burner not lighting guide covers the checks, and the cleaning habits in the Frigidaire cooktop cleaning guide keep the burners and ports clear. Do not remove panels or touch gas connections yourself.
Which one should you buy?
Buy the FGGC3645QS if your countertop already has a 36-inch opening or you are renovating, you cook with several large pots, and you want a dedicated simmer burner. Buy the FGGC3047QS if you have a standard 30-inch opening and want a center burner that covers both a low simmer and a fast boil. Neither page lists a fault that sets one apart. We are an independent service and we repair both, so you can read about Frigidaire cooktop repair if you already own one.
