So my brand new Carrier Infinity 50xt 3 ton packaged heat pump unit is in and seems to be functioning correctly except for this: When I feel below the unit, just below where the center of the supply plenum duct meets the base there is a good bit of cold air definitely flowing out into the great outdooors. This air is not leaking out of the joint where the supply duct is connected to the unit. That joint is flanged and screwed and siliconed well and I feel no air whatsoever there around the entire edge of that joint. This air is escaping the bottom of the unit just before it exits the unit. Reach through the base rail slot and there it is flowing right out the bottom, just inside the base rail where the plastic base meets the base rail. I suspect that both the base and sides are supported by the base rail and the leak is where the side meets the
base. How is this seal done???
The floor of the unit is a molded plastic, the sidewalls are sheet metal, and the base rail is galvanized. It feels like the air is flowing out at the edge of the plastic base where it meets the sidewall and/or base rail.
Has anyone seen anything like this?
Does anyone know how the air seal is maintained at this point? In particular where the metal side meets the plastic base.
Is it possible to open the right side of the unit to see this area without taking apart the supply ductwork???
My installer is going to come take a look and I would really like to give him any info or suggestions that might be helpful.
One thought that occurred to me is as follows. When the installers screwed the flanges on their fabricated supply duct into the back of the unit (that's how they did it) maybe the screws pushed a piece of the insulation board inward inside the unit. I remember that there was foil tape sealing the board to the supply opening on the back of the unit. Maybe that tape (or similar tape at the bottom of the foil board?) was popped or torn in the process and allows air to sneak between the metal wall and the plastic base if there is a small gap there.
By the way, the thermostat shows static pressure readings running around 0.25 under low air flow ranging up to around 0.8 for the highest air flow.