I have a two gas appliances - furnace (forced air) and water heater (no fan) -that vent into my chimney (see pics). I recently had a repair performed on my furnace and the technician said my venting was installed incorrectly. Specifically, she said the wye connection should have been installed on the outside part of the chimney NOT within the chimney itself (see pics). I can’t remember her exact words but she said it would be difficult to check the condition on the liner in this particular instance and recommended we have this corrected.
What do you make of this pictures? Do I have a real problem here?