The Furrion Burner Assembly for model FGH4ZSA-SS (#C-FGH4ZSA-SS-BURNER) is a suitable replacement option for the GreyStone Gas Range HFK2421A. This assembly includes the burner components, and it does contain the gas valve necessary to replace a leaking rear burner valve. Using this assembly will restore the functionality of your RV stove, allowing you to safely turn the LP gas back on. For precise compatibility and to ensure you’re ordering the correct part, it’s recommended to verify details with your range’s manual or contact our support team. We can assist you with ordering and answer any further questions to help you get your RV stove fixed promptly.