Secondary condensation Cap question

I am seeing a lot of these caps removed from air handlers and just left open. Do any of you consider this a deficiency? If not, why? Thanks for your input. See attached pic

Gary, responding from your request on the other thread.

My initial observation of your photograph:

It appears that the auxiliary drain plug is not installed (to the right of the condensate drain).

There appears to be water staining on the plywood decking below the air handling.

There is no auxiliary drain pan below the air handler (it appears it is located above a finished ceiling in the attic because of the plywood decking). There is no auxiliary condensate switch as there is no auxiliary condensate pan (A water sensor can be utilized were a pan cannot easily be installed).

Green staining on the condensate pipe indicates a condensate leakage from the suction refrigerant line above (uninsulated pipes).

As for caps missing or not installed:

As you can see by the funnel, this is used to clean out the condensate drain.

If the cap is missing air will be drawn into or blown out of the air handler. This one is an up flow air handler and will draw unconditioned air from the attic (hot and humid Florida air) into the HVAC system increasing its load, reducing capacity, increasing power consumption and reducing equipment life. This is a weatherization, as well as in indoor air quality concern.

If there is a trap located downstream and this cap is left open, the air drawn into this opening well cause the condensate level in the evaporator drain pan to potentially overflow onto the inside of the equipment.

This will also occur if there is no trap and it doesn’t matter if a cap is in place are not.

A missing cap will also allow condensate water to overflow (depending on its elevation relative to the evaporator pan).

I see this procedure around here all the time and we get into arguments with HVAC guys on a frequent basis. If the client wants the cap put on than it should be put on.

Dave, what are the AC guys saying as their reasoning for leaving these caps off?