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Read our privacy policyThe Williams 9A335 is a high altitude conversion kit for the Williams 3509821 and 3509621A furnace. The kit includes all adapters needed for high altitude conversion.
Product Includes
Orifice for installation at 2,000 to 4,000 feet.
Orifice for installation at 4,000 to 6,000 feet.
Orifice for installation at 6,000 to 8,000 feet.
1-Year Limited Parts Warranty