I have a York Stellar Plus gas furnace and during this year's furnace inspection, the Reliance Home Comfort Technician discovered that the collector box cover was cracked. Reliance has not been able to source the replacement part so I thought I'd try the Internet as their only solution was to purchase a new replacement furnace. The gas furnace is York Stellar Plus, model #P2UDD10N05701C. I'd appreciate any assistance in sourcing this replacement part

Have them take some 22/24 gauge sheetmetal and make a new one. Those type parts I believe are obsolete or will be very hard to find.