Cabin Heat Always On despite knob setting

It’s just a flapper valve on the firewall. The scat from the shroud on the stack runs to the flapper. Some folks disconnect the scat during the summer but I don’t know how that affects engine cooling. You can probably get a new valve from Vernon Gregory.

Afternoon, does anyone have a schematic of the Cabin heater? The knob is fully closed so there should not be warm air coming in at all yet my left foot roasts and I can feel the hot air coming in.